On January 8, 2013, I bought a Chevrolet Volt. If you are here then you are probably looking for information on the Volt. In my search for information, I found that some of my questions simply did not have adequate answers on the internet. This page is here to fill in some of the gaps as I have discovered a couple of those answers plus provide my own evaluation of the Volt.
I will likely be editing this page quite a bit as I learn more about this car. If you are interested, check back often for updates.
I will assume that you have read Chevrolet's Volt Site and Wikipedia's Volt Page. If you haven't read through these pages, I recommend that you do so now. The information that I will present below will make more sense in the light of the overall context of the car.
I decided to pull the trigger and buy a car without selling the cars that I have, a 2001 Yukon XL and a 2003 Ford Escape. Both of these cars are 4x4 and both can get to my cabin in the winter. The Yukon is also capable of pulling my trailer and it can haul a fair amount of "stuff" as well as seating up to 8. This was important as I had 4 children, all adults now. These cars have utility, both run well and have been reliable, but both have around 100,000 miles on them. If we keep driving them the way that we are doing now, they will be fully used up before we are done with them. Neither gets really good gas milage, but neither are really bad either. The Yukon gets about 18 mpg on the highway and 14 in the city. The Escape gets 20 on the highway and 16 in the city.
If either car dies, the other one can still get us to the cabin in the winter. If the Yukon dies, I am looking at $50,000+ for another similar vehicle that would still get poor gas milage. Further, except for it's gas consumption, I really like the Yukon, it fits me well. I want it to last at least another decade, maybe two assuming that I do. I figured that the best way that we could keep a 4x4 going for the duration was to buy another small, cheap, high milage car and take a significant milage load off both of the other two cars. I hadn't actually done anything about it until now, except think about it, because of the hassle of dealing with car dealers. However, I just helped my son buy his first car and the experiences was not all that bad. The dealers we went to (Toyota as he bought a Prius C) did not seem nearly as sleazy as I remember based on my experiences with car dealers of any stripe in the past.
I have been keeping up with the progress of electric and hybrid electric cars for several years and every time I worked the numbers on one, it just didn't make economic sense, usually by a lot. At something near MSRP, the electric cars (the Volt is an electric car) don't make sense as an alternate car. The less expensive of the light hybrids currently do make sense based on gas milage alone. However, due to some special deals, ones that will expire shortly or could expire at any time, the numbers came out differently this time. With $9,000 in government tax credits, $5,000 in outright rebates and almost $2,000 in an outright dealer discount, the $39,145 MSRP base model car came in at the same price as any mid sized sedan. I also got 0% financing. Further, this car gets 50% more straight gas milage (when operated in the gas driven extended range mode) than any conventional mid sized sedan. If I take full advantage of short range all electric driving, it can easily double the milage of any conventional gas engine car. Counting that, with the right driving conditions, it can be driven on electricity alone for months, the energy cost is half or less the cost of gasoline. Under these conditions it makes good sense in comparison to the purchase of another kind of new car. This also takes no account of the toy value of an electric car which is an important factor to me.
Hence a new base model Volt found it's way to my drive way on January 8, 2013. I drove it home from the dealer, about 15 miles away, on electricity alone, including a 70 mph stretch on the San Diego Freeway. It also made an 8 mile round trip to Costco on the battery alone and it still had an estimated 17 miles to go on the battery. I charged it up that night and then my wife and I drove 400 miles from the LA area to Vallejo the next day and then back again 5 days later. I drove right over Tejon pass (4014' elevation) and the battery finally gave up a mile from the summit. I had been driving in "Hold" mode to keep the battery at the top until I got to the bottom of the climb. A coast down the other side put 20% back in the battery and then I let it manage itself the rest of the way. The trip milage was displayed at 42.6 mpg including the impact of the energy that was in the battery. When I gassed up about 300 miles out, the overall milage was 48 mpg (which didn't take the energy from the battery into account).
I am going to deviate my "gap-filler" purpose and do a coarse summary of electric cars in general. There are many kinds of electric cars now, each designed to fill some need for some particular kind of driving. The Volt is probably closest to a general purpose car of any of them while still providing the lowest overall cost of driving if the driving range does not seriously exceed the electric only range between charges.
Electric cars are not new, there have been electric cars on the road for more than a hundred years. However, battery technology has only recently become good enough to actually use in a practical electric car. However, even the best batteries today pack only a small fraction of the energy available in gasoline or diesel. Diesel actually packs more energy per gallon than gasoline does, but the performance of small gasoline engines is typically better overall than small diesel engines although the diesel milage is better. A good diesel car can get considerably better milage than a gasoline powered car. In larger and heavier engines, for trucks, busses, locomotives, industrial generators, utility generators and ships, diesel is way better than gas except for pollution issues.
A gallon of gas will drive a modern car for 30 miles or so and weighs 6 lbs. The battery in the Volt will drive the car for 20 to 50 miles depending on driving conditions but it weighs about 400 lbs. A battery big enough to match the range of a typical gas car would weigh much more than the rest of the car, not to mention that it would be way too expensive to consider. This is the basic problem with battery powered cars, the battery is expensive and the energy density is far too low to be able to match the range of a gas car. Further "refueling" a battery powered car is an issue. It takes less than 5 minutes at the pump to refuel a conventional car. To recharge a battery powered car with the same range as a gas powered car would take a day and a half at the maximum capability of a typical 220 volt circuit. This is not even close to practical for a general purpose car. The refueling issue is a really thorny one for a 100% electric car. Note that the Tesla Model S is a special case. It has been designed so that it can fully charge in about an hour at a special very high power charging station.
Electric Cars. The Nissan Leaf, Toyota RAV 4, Ford Focus Electric and the Tesla Model S are examples of current production 100% electric cars. They typically have a range of 100 miles or so (the Ford is 74 miles) and can be recharged overnight. The Tesla models tend to go further, but cost a lot more. This recharge time is sort of hard limit on the range of the car. The cars are designed to run within 50 miles of home base so that it can be driven home to recharge overnight. They use the lowest cost fuel available at most locations, 1/6 to 1/2 the cost of gas depending on local electricity rates. They don't carry the complication and cost of a gas engine as the light and heavy hybrids do. They are also typically small cars, 4 seats with little cargo room.
Light Hybrids. The Toyota Prius family (less the Prius Plug In), Honda Insight, Ford Escape Hybrid, the new Ford Fusion Hybrid and a raft of vehicles that have a hybrid capability added, are examples of a light hybrid. These cars have a fairly small battery that is good for maybe a mile or two of total electric range. The purpose of the small battery and electric motor is basically to get the car across the crosswalk efficiently where a gas engine optimized for high engine efficiency at higher engine speeds can take over to run the car and recharge the small battery. The engine itself has been designed to hardly run at all at low speed. It may not even be able to run at a conventional idle. By sacrificing the low speed performance of the gas engine and letting the battery/motor handle that, the efficiency of the gas engine in a fairly small high rpm configuration can be much better than a general purpose gas engine that needs to support the full speed/load range of a conventional car. This is why light hybrids get better gas milage, they use each power source to it's best advantage. However, they are still entirely gas powered cars. The battery recharges by burning some gas in the engine while the engine is running efficiently. The recharge strategy is to keep the battery near the high end of the acceptable State of Charge (SOC).
Note that the term "light" hybrid doesn't necessarily mean a light car. There are full sized pickup trucks that still have a V8 engine, and many mid sized light hybrids. The are several reasons for these "light" hybrids to exist. They do get better gas milage than the conventional gasoline powered car so that they can increase the fleet milage of a particular manufacturer's production. They bring hybrid characteristics to more brands of cars so that the dealers for a brand such as Lexus can also sell hybrid cars as an upsell to anybody that walks in. The extra cost of this battery, motor, electronics and transmissions is not that large in comparison to the cost of a $50,000+ car so that an upsell is possible. They do allow the engine size of any car to be reduced, providing the passing power and acceleration of a larger engine to a car with a smaller engine plus battery/motor. They do allow the engines to be shut down when stopped so that the car can get up to a reasonable speed on battery power while the engine is getting started.
Heavy Hybrids. A heavy hybrid, or as more commonly called a plug in hybrid, is similar to a light hybrid except that the battery is much bigger. The only two examples that I know of are the Chevy Volt and the Toyota Prius Plug In hybrid. The larger battery is usually intended to be recharged from some external source, the gas engine does not recharge it in any substantial way. That would be inefficient. The light hybrid tries to keep the battery nearest it's full state of charge. The heavy hybrid tries to use the battery until it reaches it's lowest state of charge and then maintains it there, expecting that the battery will be recharged by an external, less expensive than gas, source. When the battery is discharged to it's lowest allowed state, it still has useful charge in it and the car then operates as a light hybrid by keeping the battery near the lowest acceptable SOC. Ideally the battery would be big enough to handle a day's driving and be recharged overnight from lower cost grid power.
Chevrolet doesn't call the Volt a heavy hybrid, but it acts somewhat like one. GM calls it an electric car with a "range extender" gasoline engine. See the interview with Andrew Farah, the chief mechanical engineer for the Volt, for the details of the rather conceptually complex drive mechanism. The Volt either runs as a full electric when sufficient charge is in the battery, or it runs as a gas-electric serial hybrid where the motor/generator set electrically drives the main traction motor. Only on rare occasions does the motor mechanically contribute to driving the car in a parallel hybrid mode. Unlike a light hybrid, the traction motor does most of the propulsion and is sized accordingly. The traction motor in the Volt is considerably bigger than the one in most light hybrids.
Alternate Fuel Electric Car. Opposed to recharging a battery with electrical energy from the power grid, an alternate fuel electric car attempts to convert energy from some chemical fuel to electric energy to drive an electric motor without using a gasoline or diesel engine. There are none of this kind of car in current production although there are several in development. The typical conversion mechanism is called a fuel cell and one possible fuel is hydrogen. The waste product is water when using hydrogen as fuel. The EPA and AQMD (Air Quality Management District) love this kind of car. Hydrogen is difficult to carry in quantities needed to drive a car for a whole day but that problem is being solved. To make this work, a hydrogen fueling infrastructure must be built out. This will take time and a lot of money. There is one hydrogen fueling station, branded by Shell, that I know of on 190th street in Torrance, just a few miles from my home. The fuel cell itself does not lend itself well to the rapidly changing load conditions that are common in electric cars so the fuel cell car will likely carry a small rechargeable battery. The motor draws energy from the battery when it needs it and the fuel cell keeps the battery charged as the fuel cell cannot easily react to the rate of change of load current that is part and parcel of electric driving. The battery allows the fuel cell to generate the average current required and the battery provides the peak current needed and absorbs excess current from the fuel cell when the load current is low.
None of these cars are ideal for everybody. If you want a car that is closest to a regular car, but gets better gas milage, then the light hybrid, like a Prius, is the best choice. It will provide 30% to 50% better gas milage than a conventional car, but it reaches a pretty hard limit at that point as the efficiency of a light hybrid is capped by the efficiency of the gas engine. If you do not have any place to plug in a heavy hybrid or full electric, then the light hybrid is the ONLY choice for an electric car. Further, a light hybrid is currently the least expensive of all the hybrid vehicles. They cost more than a really small gas car, but also will do much better gas milage.
The full electric car has a serious limitation due to the limited maximum range and the fairly long recharge cycle. If you have a charge station where you work (even better if your employer pays the power bill) then you can use one for a long commute. Just make sure that you will be at work long enough for it to recharge enough to get home. It could take longer than a normal working shift. Full up electric cars also tend to be much more expensive than conventional small cars, however the $7500 Federal tax credit applies for as long as that program lasts. If your two way commute falls into the range of an electric car, and you have a high rate charger and a low power rate, then a fully electric car will be the least expensive to operate. If your weather is really cold or really hot, be aware that intensive climate control inside your car can cut your range in half.
The alternate fuel vehicle practicality will depend entirely on the availability of refueling facilities that you can use and the actual cost of that fuel. As of 2013, they are still a ways down the road.
The heavy hybrid, such as a Volt, needs to be plugged in to charge to be practical. If it is never plugged in, it is just an expensive light hybrid that doesn't get as much milage as the best purpose built light hybrids do. If it can be plugged in and the daily milage doesn't exceed it's all electric range by very much, it's operating cost can be one third of a conventional high milage gas car and half of a light hybrid. How much less depends on your local electricity rates and gas costs. Like a conventional car or a light hybrid, the heavy hybrid is not range limited except by driver endurance. The heavy hybrid is unlikely to get the same gas-only milage as a light hybrid due to the extra weight of the battery which must be hauled around, however, it's milage operated as a light hybrid is close to purpose designed light hybrid cars.
While I was looking at light and heavy hybrids, I didn't pay much attention to the full electrics. They didn't have the range to meet my needs. I needed to drive 103 miles with a 5500' climb at the end without needing a recharge and with high probability of getting there. I would also like to come back without refueling. This was clearly outside the realm of possibility of a full up electric car unless I was willing to pay more than $90,000.
Just for curiosity, I took a quick look to see what size battery the full electric cars held and I find that some have a battery that is only 50% bigger than the Volt's battery, yet they have 2.5 times the range. The cars are not much lighter than the Volt, every little bit helps, but it still doesn't make a lot of sense. The Volt may be considerably less efficient, or there MAY be a numbers game involved. I believe that the Volt's numbers are actually conservative based on my own tests on my car.
I did a little research and gathered the cost, weight, battery capacity, claimed range and motor size for the currently available electric cars. I counted the Volt as an all electric car for this informal study.
|Make and Model||Base MSRP||Battery Capacity (kWh)||Motor Capacity (kW/HP)||Weight (lbs)||Claimed Electric Range (miles)||EPA Rated Electric Milage (MPGe hwy)||Notes|
|3781||38||98||Includes range extender gas engine, 35 to 50 mile full electric range by test|
|Toyota Rav4 EV||$49,800||41.8||115
|3385||<100 (not specified)||92||Smallest motor, but 107 hp is enough to get around. Range inferred from Nissan's Leaf Cost calculator which does not allow a range of more than 100 miles|
|Ford Focus Electric||$39,200||23||92
|Toyota Prius Plug In||$32,000||not rated||60
|3165||11||95||Shortest electric range|
|Tesla Model S||$52,400 - $90,000||40 to 85||not rated||4647||160 to 300 miles||not specified||Most expensive but also very quick, 4.4 seconds to 60 mph|
It appears that there might be some craftsmanship going on with the specs.
The Rav4 has a battery that is about 2.5 times the size of the Volt's battery and the range is about 2.5 times as large. The Rav4 is also heavier than the Volt, likely due to the larger battery which could amount to an additional 600 lbs by scaling from the Volt battery. This makes some sense.
The Tesla Model S (in the shorter range version) has a battery that is 2.5 times the size of the Volt's, but the range is 4 times and the car is even heavier.
The Ford Focus Electric's battery is only 1.5x the size of the Volt's, but it's range is twice the Volt's range. Either Ford is doing something right (or Chevy is doing it wrong) to result in this discrepancy.
The Nissan Leaf's battery is only 1.5x larger than the Volt's, yet it range is 2.5 times the Volt's range. The car weighs about the same as the Volt. Something isn't right here.
The Leaf and the For's battery size is about the same but the range is 30% different.
The Prius Plug In range is short, the battery size is unspecified. This car may not count as an electric car, but I put it in the table for completeness.
Note that the specs that are listed for the Volt are the numbers published by GM. The range is specified at 38 miles on the battery, I get between 35 and 50 depending on the presence or absence of hills. Gas milage is also rated at 37 mpg when running on gas. I consistently get 42 mpg on gas. It sounds like Douglas Adams was right. I have not done enough running tests to validate the MPGe spec of 98, and I don't know exactly how the EPA calculates it, but since the range is better than spec, it is likely that the MPGe number is also at least meeting the spec.
I elected to purchase a Volt even though the gas-only milage of the Volt is not quite as good as Prius or Prius Plug In. The $15,000 in rebates and tax credits available for the Volt had an impact too. However, when the plug in performance is factored in, the Volt has lower cost to operate than any Prius. The US Government rates the Volt at 37 MPG operating as a light hybrid and 98 MPGe when driven optimally as a heavy hybrid. I am getting 42 mpg on gas alone, better than the government test based claims. There are claims by some drivers that they have gone for months without buying any gas at all. The battery is as big as it can practically get and still recharge overnight on 110 VAC. It will recharge in 4 hours on 220 VAC with the addition of a $2,000+ high rate charger.
Light hybrids do not qualify for the Federal and State tax credits, $9,000 worth in California. I do not know if the Prius Plug In qualifies for the tax credits and it didn't have the GM rebates and 0% financing. This made the Prius and Plug In Prius not cost effective for me.
The car is a 4 seater with a hatch back. The hatch back with fold down rear seats is also important to me as it makes for a reasonable cargo area in two or three seat mode.
GM has done a fair job of noise suppression. There is some road noise, more than the Yukon, but less than the Escape. There is hardly any mechanical noise, even with the gas engine running. The car rides smoothly. It also rides pretty low to improve it drag ratio, therefore it doesn't have a lot of ground clearance. It would not be a good idea to take this car off road, nor try to put tire chains or cables on it. GM specifically recommends against tire chains or cables, there is not enough room for them within the limited volume in the wheel wells.
The seats are comfortable and there is enough room inside for me, I am 6'4" tall. However, pushing the seat back so I can get in pretty much eliminates the leg room for a passenger behind me.
The radio is confusing, I had to read the book to figure out how to use it properly. It has both line-in and USB connections for an iPod or MP3 player however, the software in the in the radio is confusing, no where near Apple-like, when using it to control an iPod. It does play a CD in a conventional fashion. The base radio has XM satellite radio capability for some period but I will not likely renew it when the introductory period expires. The car also has On-Star, a radio link that can be used as a cell phone (extra charge) and to contact GM in case of trouble. The rest of the controls are pretty conventional.
I've had a little more time to play with the "Infotainment System" in the last few days and my initial experiences holds. The playlist function simply does not work with my iPod. It takes a long time to even load the playlists and then when one is picked, it plays an album that isn't even in the playlist instead. The select by Album and Artist mode seems to work reasonably well. This may be a problem between the firmware in the radio and the OS in my iPod touch, iOS 6. My wife's iPad runs iOS 5 and it seems to work. Her older iPod touch runs iOS 4 and it works ok. Both of those have about 15 playlists. My iPod touch has 114 playlists and is clearly not handling them well. The list is sorted alphabetically and it just stops partway down the list and has dozens of blank lines. If I pick a blank line, it plays something. If I pick a named playlist, it plays something else, but generally not the playlist that I picked. I think that I have overwhelmed it or that there is a bug in either iOS 6 or the Volt's software.
An iPod can be connected via the line-in connector and then it works fine from the iPod screen, but to access that screen, the dock connector has to be unplugged. It is not currently possible to play from a playlist and charge the iPod from the car's USB port at the same time. I can charge it from a car charger and use the headphone jack to connect to the car.
Speaking of software, I asked the GM support team about how software updates are done on a car. They say that some have been pushed out over the OnStar link to the car, but most are handled as a vehicle recall at a dealer.
The car has two LCD displays, one where the speedometer would be and one in the center console. The driver's display provides a lot of info besides just speed. Wrapped all around the speed display is the status of the battery, operating modes, warnings, fuel level and some selectable other reports. If the battery runs out of juice, then a large fuel level indicator moves into the place of the battery level indicator. There is a selector knob on the dashboard to display other modes, such as the power display, tire pressure, a power routing graph, trip meters, alerts and messages.
The large ball on the right is a driving efficiency indicator. The driver is supposed to keep the ball in the middle. If the ball moves upward, this means that excess acceleration is being applied, reducing efficiency. If the ball moves lower, it means that the brakes are being applied. Even regenerative braking is inefficient. This means that the driver previously dumped too much power into kinetic energy (movement) and now has to recover some of it or maybe none of it if hard braking is required. If the ball turns yellow, for example when braking, then the friction brakes are being applied. If it turns yellow when accelerating, then the motor current is too high and there are excessive electrical losses in the battery, wiring or motors.
A very useful display is a power gauge that shows the instantaneous power being drawn or supplied to the battery and the power being drawn from the gas engine. The kW number in the center of the graph appears to be the electrical power delivered to the motor and other major loads, such as the climate control system. In this case, the battery usage is fairly low but the car is still running in full time electric car mode with 18 kW being consumed by the motor. At the time, I was climbing a shallow grade on I-5 at 65 mph. The normal flat interstate cruise power is around 10 kW. Around town, the car cruises at about 5 kW on a flat road at 40 mph.
In this photo, I have switched to Mountain Mode and since the battery level is below the set point for SOC, the engine has come on and is charging the battery to get ready for some mountain climbing. When needed, the engine does appear to charge the battery directly.
There is also a center console mounted display to describe power management for the hybrid drive system. There are three screens for power management. They are pretty simple to interpret. I would have preferred that they provide more information than they do. I would like to see, for example, when the friction brakes start to apply however, this information can be deduced from the battery instantaneous power gauge and the efficiency indicator on the driver's display.
The Volt drives like a conventional car. If you don't pay any attention to the hybrid drive and just drag the "shift" lever to "D", you can drive away. There is no ignition key. There is a power button to turn the car on. The car will only turn on if the wireless entry key fob is within a few feet of the car. The driver's door will unlock and lock again with a button on the outside of the door if the key fob is within 3 feet of the car so you don't even have to take the key fob out of your pocket. The parking brake is electrically set and released with a button. It also releases automatically if you just drive away. The headlights are automatic.
There is a 12 volt standard car battery under the floor of the cargo compartment. This battery can be used to jump start another vehicle. It also powers the electric parking brake and other systems when the high voltage traction battery is shut off. If the 12 volt battery goes dead, the car won't "boot" and cannot be driven.
The car does not have a spare tire. There is really no place to put it. Instead of a spare, there is 24 hour roadside assistance, a tire pump and a tire leak sealer kit so that the leaking tire can be chemically patched and then re-inflated. There are no wheel removal tools or jack.
The car has a basic alarm system that will blow the horn if the car is entered improperly. The car will also be immobilized. The charge cord is also alarmed. Chevrolet doesn't claim that the alarm will make theft impossible, but it should deter all but the most dedicated car thief. But get a Club anyway.
Before I get into the operating performance, this is the engine compartment. The black blob on the left center is the gas engine. The blob on the right is the power control electronics and the motors. It is obvious that this is not a car for a backyard mechanic, there is very little that is user serviceable except for oil, brake fluid, coolant and windshield washer fluid. The coolant is the orange stuff in the tanks at the left and front. There are separate systems for the engine and the electronics. I have this same coolant in my Yukon. I have not touched it for 12 years and it is still good to go. The bright orange cables are high voltage cables to the battery. They are clearly colored so that, in an accident situation where a rescuer might have to use the jaws of life to cut somebody out of a mangled car, the cables can be seen and avoided.
The motors themselves are permanent magnet rotor, AC synchronous motors. Electrical engineering types will know what this means, but basically is a highly efficient and reliable configuration. The planetary gear set is located between the engine and motor assemblies.
I did some performance tests on the Volt on my first whole day of driving. Overall, it is good. I am not a sport driver but the car will indeed get out of it's own way. It will run on battery power at most speeds until the battery is depleted. You have to cruise way beyond the legal speed limits in California (70 mph on some freeways) to cause the gas engine to start before the battery depletes. The main electric motor is 111 kW, about 150 hp, and is very responsive at all speeds. The gas motor is 1.4 L, 80 hp or about 60 kW. The gas motor drives a matched electrical motor/generator of 53 kW. This creates electrical power that drives the main drive motor when on gas power. This mode is a serial gas-electric but the car is not as responsive here. The gas engine can make only 80 hp and a depleted battery can add some for a short burst, such as when passing, but it cannot do that for very long. There is also an operating mode where the gas engine is indirectly mechanically coupled in parallel with an electric motor to provide for higher efficiency while cruising. However, it is not at all obvious when this mode is engaged.
The car does not have a conventional transmission. This is not necessary for an electrically driven car. There is a planetary gearset and 3 clutches that direct mechanical power between the engine, both motors and the front wheel drive assembly in various combinations. The transitions between these modes is virtually undetectable. It is even difficult to determine when the gas engine actually starts. This is a slight increase in noise and a small amount of vibration in the steering wheel to indicate that the gas engine has started. At freeway speeds, even those indicators are hard to detect. When the gas engine runs, it does so in a narrow RPM range. This is based on the pitch of the engine sound while it is running. As the load changes, for example climbing a grade, the loudness of the engine sound changes without a lot of pitch change.
Basically, there are three power sources, two motors and an engine. The Volt's power train can apply the power of two of those three sources to the wheels at any given time but not in all possible combinations. The Volt's computer determines the most efficient way to arrange those connections at all combinations of speed and load. The Volt appears to make it's decisions based on two primary factors, protection of the battery and then efficiency. For example, when we left Vallejo to return home, the temperature was just below freezing. The engine came on virtually immediately even when the battery was fully charged. A message displayed on the driver's screen said that the engine came on because the car was too cold. Apparently, the battery wanted some heat.
The car has a 16.5 kWh battery, of which only about 10.2 kWh is actually used. The lifetime of Lithium batteries is materially improved if the battery is never fully charged or discharged. This is why the battery can be warranted for 8 years. The Volt keeps the maximum State of Charge (SOC) of the battery at 80%. It won't charge higher than that under any conditions to protect the battery. The minimum SOC is normally limited to 30% but is allowed to dip to 25% in some conditions.
Power steering is electrically assisted. Since the car runs on electric mode much of the time, hydraulic or vacuum assisted equipment that would normally be run as an engine accessory has be be run electrically instead. This includes the air conditioning, cabin heat, power brake assist and cruise control.
There are four driving modes, Normal, Sport, Mountain and Hold. Hold was a new feature in 2013 in the US, older US Volts don't have it.
Normal Mode is where the car should be driven most of the time and it is the default when you turn the car on. It will run the car completely on the battery until it is discharged to it's minimum State of Charge (SOC). The gas engine will then start and run the car when it is efficient to do so. Even with the battery at the minimum SOC, the car runs as a light hybrid, drawing power from the battery to start from a stop and even under some moderate speed cruise conditions. If the SOC gets too low, the gas engine will start again and run the car while bringing the battery up to 30%. Regenerative braking is also used to put some charge back in the battery by recovering the some of the kinetic energy that the car carries while braking.
Sport Mode makes the car feel more responsive while actually doing very little. It doesn't change the acceleration, deceleration, top speed or time to 60 mph (about 9 seconds) in any way. What it does do is make the car respond more quickly to accelerator pedal pressure. From the driver's perspective, it makes the car "feel" more responsive. From a passenger's perspective while riding with an aggressive driver, it will throw them around about the same. It is harder to make smooth starts in Sport mode as the pedal is very touchy. Since I am not an aggressive driver, Sport mode doesn't do much for me.
Mountain Mode sets a higher lower bound to the SOC which then appears to be about 50% charge. If the battery is not at the higher limit already, the car will charge the battery from the gas engine to get the battery level up to the new minimum level. The raised lower limit of SOC allows the car to perform better under the higher loads of climbing a grade. If the battery has been consumed by regular driving, this mode should be entered about 20 minutes before hitting the mountain to allow the gas engine to put charge back into the battery.
However, Mountain Mode is not necessary to climb a grade. While climbing Tejon Pass southbound on I-5 with a discharged battery, the car was able to maintain 59 mph all the way up the stiff grade on the 80 hp engine. As the grade changed slightly during the climb, the car would alternately charge and discharge the battery a little while keeping the gas engine fully loaded.
Hold Mode essentially stops the car from using the battery very much. There are special purposes for this mode, but I used it to retain as much charge as possible to climb Tejon pass northbound to see if it could take the whole mountain on electric power alone. It almost did.
Hold mode was designed for, and first applied, in Europe on earlier than 2013 models for some special conditions in some cities. There are driving restrictions in some places in Europe that all-electric vehicles are allowed to circumvent. The Hold mode is there to allow a commuter to drive to the city on gas power and then drive inside the city on electric power.
In Hold Mode, the car will attempt to keep the battery at the SOC it was in when the Hold Mode was activated. The car will again operate as a light hybrid with the SOC remaining at the point where it was held.
The brakes are a combination of conventional anti-lock friction brakes and regenerative brakes. Regenerative braking uses the kinetic energy of the car to generate electricity that is returned to the battery. As the brake pedal is pressed harder, more regenerative braking is used until such point as it cannot slow the vehicle as fast as the driver wants. Then the friction brakes are applied, blowing off the rest of the kinetic energy of the car as heat. Overall, the brakes work really well with little hint of when the transition from regenerative braking to friction braking occurs. A hard stomp on the pedal will stop the car very quickly.
The cruise control works like any other car in trying to hold the car speed at certain set point. If the battery is nearly discharged, the car may leave the engine running during this time as well. For best efficiency, the cruise control should be disabled by tapping the brakes and the brake pedal can be used to maintain vehicle speed through regenerative braking. The engine will shut off virtually immediately after exiting downhill cruise control.
The "shift" lever has 5 positions, Park, Reverse, Neutral, Drive and Low. The only one that differs from the conventional usage is the Low position. It is not a lower gear. It just changes the way that the car uses regenerative braking, making it much more aggressive. In Drive, when the accelerator pedal is released, the car coasts fairly freely but still does some regenerative braking. In Low, it actively decelerates using more aggressive regenerative braking, so much so that the vehicle speed will actually get pretty low "coasting" downhill as energy is recovered an put back in the battery. If you have ever driven an "Autopia" car at Disneyland then you are familiar with the feel. Press the pedal to go, take your foot off the pedal to stop. While driving around town, this mode works pretty well and seems to increase the all electric range by maybe 5 miles. If you want to coast without braking, very light pressure on the accelerator will allow car to coast without slowing due to regenerative braking. Using this method, it is only necessary to use the brakes below about 5 mph or when a really fast stop is required. Note that when braking in this mode, the brake lights do not appear to activate so a driver behind you may not realize that you are slowing down.
Do not expect the regenerating braking to materially increase the state of charge of the battery. This is one of the questions that I had that I could not find an answer to on the Internet. The answer is, you get some back, but not a lot. Driving northbound up Tejon Pass in I-5 in Southern California presents a long climb with quite a bit of up and down action after the initial climb. This essentially drained the battery which I had kept a maximum using Hold Mode until that the start of the climb. Coasting down the other side and maintaining a safe highway speed down the steeper north slope returned about 20% of the charge back to the battery.
The reason for the low rate of return of energy is that while dragging the car to altitude to build potential energy that could be reclaimed on the way down, the car blew off most of the energy applied in unrecoverable wind resistance, tire rolling resistance and electrical losses within the car itself. Further, on the way down, these same forces were at work eating up a very big chunk of the potential energy gained in the climb before it could be applied back to the battery charge. Hence, 80% of the work done going up and down was eaten in unrecoverable losses.
The Volt also has some maintenance modes.
Engine Maintenance Mode (EMM). It is possible to drive the Volt in such a way that the gas engine never starts. EMM occurs about every 6 weeks if the engine has not run long enough during normal driving. This is done to circulate lubrication fluids through the engine to keep it well lubricated.
Fuel Maintenance Mode (FMM). It is also possible to drive in full electric mode such that little or no gasoline is burned. The gas in the tank can get stale and then the engine may have a hard time starting when it needs to. Hybrid cars are especially sensitive the gas engine's quick start. FMM watches the age of the fuel in the tank and will force some of it to be burned off so that it can be replaced with fresh fuel. The mode will run until enough old fuel is burned AND it is replaced with new fuel. Virtually every hybrid car uses a high compression engine to obtain better high speed performance so it requires pre-ignition resistant premium grade (91 octane) fuel.
If the car runs out of fuel, it can run 3 to 4 miles on electric power to reach a fueling station to replace the fuel. If the battery gets too low in this mode, the car will decelerate to a stop and will be immobile until it is refueled with enough fuel to get to a fueling station.
The car has a "hill holder" mode. When the car stops on a hill and the brake is released, the car will slowly drift backwards. This allows plenty of time to get your right foot from the brake pedal to the accelerator pedal.
I've been driving the car for about 3 weeks now and I am very pleased with it. On gas alone, I get about 42 mpg vs 37 mpg claimed. On electric alone, I am consistently getting 42 to 47 miles, vs 38 claimed unless there has been some serious hill climbing. Aggregate "fuel" milage is above 60 for all the miles driven, many of those were on gas. I have learned how to drive it for good efficiency. I cruise on the freeway between 60 and 65 and hardly use the brakes around town, using the "Low" shifter setting instead. The only complaint is that the visibility to the rear and rear quarters is not as good as many other cars. The ride is smooth and quiet. What I interpreted as noticeable road noise is just because there is no engine noise to drown it out.
The car is very responsive, making a quick pass is easy. Hill climbing is good on gas, excellent on battery.
I have been reading and thinking about the details of the mechanics of the Volt and I think that I have most of it figured out. The car really is highly engineered and Chevrolet did a good job of it. It shows in how seamlessly the car operates. Even when the car changes operating modes, I can only detect it reliably be looking at the power graph on the driver's display and listening for the engine. There are no "gear shifts" that can be felt. There are transitions between drive modes but they are done smoothly and in such as way as they are not felt.
Motor Trend published an article in 2010 about what makes the Volt tick. There are some good diagrams there that show the details of the magic gearset that makes this car work. However, here is my take.
There are better diagrams of the Volt transmission arrangement at David Roper's Chevy Volt Page.
Note that there are electrical interconnections that are not shown in my diagram. Basically, electrical power is delivered by a power control system to and from the motor/generator and the battery. Power is also delivered by the power control system to the main motor to actually drive the car and maybe also from the main motor for regenerative braking. The motor/generator operates as a generator most of the time, driven either by the engine or by the planetary gearset during some regenerative braking modes. The motor generator is used as a supplemental motor only above 70 mph when in electric mode. In extended range mode, engine torque can be transferred directly through the motor/generator shaft to the planetary gearset as well but the main motor has to be driving the gearset as well for this to work. The gas engine cannot drive the car by itself.
A couple of points have to be made before going into the details of the various modes. The main 111 kW motor is connected to the sun gear of the planetary set all the time. The driving wheels are connected through a differential gear and a reduction gear to the planetary gear carrier all the time. This is one reason that the car should never be towed with the front wheels down. This would backdrive the planetary gearset and motor and is likely to cause serious problems.
Normally, the ring gear is clutched to the gearset housing so that it does not rotate. The whole planetary gearset then operates as fixed reduction gear. In order for the motor generator to come into play, that clutch has to be opened and the clutch to the motor generator has to be closed. These clutch movements should be made at zero relative speed so that the clutches are never allowed to slip like the clutch of a conventional manual transmission. Since a computer controls all this stuff, the torque delivered by the main motor and engine/generator can be adjusted so that there is zero net torque at a clutch when it is opened or closed.
The change of modes at 70 mph is driven by the acceptable speed range of the main motor. The transmission is normally configured as a one speed transmission. This is perfectly acceptable, the main motor does well from 0 to 70 mph. However, at above 70 mph, the main motor is turning too fast to be efficient. The ring gear is then unlocked so that the motor generator can be coupled to the ring, thus turning the planetary gearset into a continuously variable transmission and allowing the main motor to operate at a lower speed while the motor/generator adds additional power to allow the car to drive faster.
There are several operating modes for the Volt. Within each of those main modes, there is a change of operations at certain speeds and loads usually around 70 mph although the 70 mph number is not magic. Some information from Chevrolet indicates that in extended range mode, this transition can happen anywhere between 30 and 70 mph. When it happens all depends on what mode produces the best efficiency under the current driving condition.
Below 70 MPH the ring gear is locked to the housing by a hydraulic clutch and the main motor provides all the power to drive the car via the planetary gearset operating as a simple reduction gear. The motor/generator and engine are disconnected and off.
Below 70 MPH and with a depleted battery, the car shifts into extended range mode. The motor/generator is spun down if it is running at all and then it is declutched from the planetary gearset and spun down to zero if it isn't there already. The clutch between the motor/generator and the engine is closed and the motor/generator is then used as a starter motor to spin up and start the gasoline engine. The ring gear is still locked. The car is now in a serial gasoline-electric mode, sometimes called a serial hybrid. The engine and generator create electricity which is divided up by the power control electronics as necessary to drive the main motor and to sustain the currently programmed state of charge for the battery. The main motor is still providing all the direct motive power for the car up to an average of 53 kW which can be supplied by the generator and supplemented by stored charge in the battery when required up to 110 kW. The car is operating like a light hybrid where the battery is both charged and discharged a little depending on the immediate energy needs of the car. The engine is operating at a constant speed with variable load.
Regenerative Braking Mode is still not quite clear to me. I have seen no mention that the main motor is used as a generator, but I do not see any reason that it could not be. It is the same motor type as the motor/generator so that it can be run as a generator. This would be the simplest way to do it in full electric mode below 70 mph. None of the clutches would have to be changed and the power control electronics could handle it all. The car shifts in and out of regenerative braking mode a lot and the designers of the car would probably not want to the clutches to cycle and wear. Above 70 mph, the smaller motor/generator is also engaged so that it could handle regenerative braking as well however the wind load is so high at that speed that regenerative braking may not be required. Perhaps, both motors would do it so that the computer can control the loads placed on the sun and ring gears so that it could manage the speeds of both motors. In extended range mode, the motor/generator is also connected so that there would be no significant difference in configuration as the full electric mode above 70 mph other than the engine is still connected. When the cruise control was on and I was trying to maintain a speed of 65 mph going downhill, I did notice that the engine kept running when I thought that it should have stopped. Maybe this is done to prevent wear on the engine clutch as well. These conditions will require more reading and experience to figure out.
On another trip to Lake Camanche, about 400 miles, I drove it a little differently. I was in normal mode when I left the house and I only got as far as the highway 14 and I-5 intersection, 36 miles, before the battery depleted. This was due to a lot of hills before I got there. Hill climbing does a number on the battery.
At that point, I switched to Mountain mode to recharge the battery in preparation for climbing the Tejon pass. By the time I got to the beginning of the grade, the car was at about 40% charge. It drove very well up the grade with plenty of power for passing if required. By the time we got to Gorman, basically at the top of the pass, the battery had reached the setpoint of 50%. Over the top of the hill, I switched back to Normal mode, but since the car was in extended range mode, it didn't show me any battery capacity at all. Coasting down the other side put some more power in the battery which I could see on the Power Flow display on the center stack.
Running over the mountain and charging the battery really hit the gasoline range pretty hard, it was reporting 117 miles left on gas at Grapevine (the bottom of the steep grade). The long downhill grade to Bakersfield was on battery power alone. However, during that time, the milage prediction for gasoline increased by about 1 mile per mile traveled all the way to Bakersfield. I stopped at a Costco on highway 58 near the freeway to fuel up, at that point, the car said that there was 148 miles left on gas. That 31 mile increase was almost exactly the same as the distance between Grapevine and highway 58. Since the car used gas to charge the battery before I hit the hill, the electric power consumed after the grade was counted as "negative" gas consumption as I got that energy back. After refueling, the car reset it's operating mode to electric as there was some small amount of usable power left in the battery and it showed me that I had 3 miles to go on the battery. That was all that was left from the the ride to Bakersfield after leaving the mountain.
While operating at freeway speeds going north on highway 99, the gas engine ran continuously, alternately charging and discharging the battery around it's depleted setpoint as a function of speed and load. However when we got off highway 99 in Stockton and started traveling on highway 88 at reduced speed, about 50 mph, the car started shutting down the engine at times and operating on the battery for a mile or so at a time. The overall reported gas milage was 45 miles/gallon taking into account of the usage of the battery on the first port of the trip. I got to Lake Camanche with about 100 miles of gasoline range remaining.
There were periods of the trip, both in electric and extended modes, were the A/C was running in ECO mode. This didn't seem to consume a lot of power even though it was very comfortable inside the car.
On the way back from the trip to Lake Camanche near Stockton CA, I hit the I-5 going up the Tejon pass from the north. Like the last trip up this grade several weeks ago, I had a depleted battery. Unlike the last trip, I was in cruise control at 65 mph. The car held 65 mph quite a ways up the hill by running the engine at a high level of output power and then dragging more out of the "depleted" battery. The main motor was drawing about 50 kW at the time, the power was being sourced pretty equally between the the engine/generator and the battery. Then the car went through a transition. The engine dropped in power abruptly and the battery kicked in for the full 50 kW for about a second, then the engine came back on and the battery power dropped back. I think that this is the transition to series/parallel mode where the engine/generator is connected mechanically to provide part of the driving power without converting it to electrical power first. This went on for a mile or so then the car decided that the battery was depleted as far as it was going to let it and then the car beeped and displayed a message saying that "the propulsion power is reduced", meaning that the battery wasn't helping anymore. The car's speed drifted down to 62 mph and hung there for a bit. Then the grade reduced and the car started dumping some energy into the battery and the message went away. Then the car went though another transition similar to the one before, probably as it was disconnecting the "direct" drive mode. From there on out, it was able to maintain 65 mph on the reduced grade and charge the battery as well back to a normal minimum state of charge.
While going down the south side of Tejon Pass, which is not as steep, the cruise control acted pretty much as it had on the last trip several weeks ago. The gas engine continued to run at low power. However, a few times on shorter steeper sections, the gas engine shut off for a few seconds. Then it occurred to me what was happening. I turned off the cruise control and let it coast. The car would only get up to 65 mph occasionally on the steeper sections. It spent most of the coast at 63 or 64 mph. While the cruise control was on, it needed the engine to maintain the vehicle speed at the cruise control set point as it could not run with the battery in a regenerative braking mode and a discharge mode at the same time.
The winter snow was sufficiently melted in the San Bernardino mountains such that the tire chain restrictions were lifted and I could take the Volt to my cabin which sits at an altitude of 7000 ft. So we headed east from our home along the 91 freeway until the battery ran down 48.8 miles down the road. There was heavy outbound traffic so that the trip consisted of about 10 miles of city driving and then variable speeds on the freeway ranging from stop and go to cruising at 55 to 65 mph. There is also a net increase in altitude of about 1000 ft to Corona where the battery finally died. I drove the rest of the way on the engine, but there were stretches at cruising speed where the engine shut down and we ran on the battery for a mile or two. From Highland, where highway 330 starts, to my cabin is about 22 miles and the net climb is 5500 ft. The car had enough power to handle the grade just fine.
When we got to the cabin, I plugged it in to charge it so we'll start on the trip down with a full battery. There is some up and down action, most down, so that when we go home, the battery will be running around full charge. I want to see what regenerative braking does when the battery is already full. Will it overcharge? Will it refuse to regenerative brake at all? I don't know at this point. On future trips, I will try the downhill run on a 50% battery (Mountain mode on the way up) and with a depleted battery (Normal mode on the way up) without recharging at the cabin.
I will try coasting downhill in Low as I know that coasting in Drive will cause the car to go too fast. I suspect that the car will not descend the grade fast enough in Low and I will block traffic. I can modulate the regenerative with the brake pedal, but I run the possibility of using friction brakes to some extent.
There is a way, however, to set a regenerative braking level between what is provided in Drive and Low. The method is to simply use the accelerator pedal lightly in Low. If the car is coasting too slowly, I can apply a little pressure to reduce the regenerative braking aggressiveness so that I reach the speed that I want.
I charged the car up at the cabin and ran a test of the remote start feature. This allows the car to stabilize it's cabin and battery temperatures through either heating or cooling. This takes some power though. If the car is plugged in, it will draw some of that power from the grid, but on the 120 VAC charger, more power is needed than the small charger will provide so that it draws power from the battery too. After the remote start function has done it's job and shut down, the battery will recharge. The car drew 0.8 kWh during the remote start process which took about 50 minutes.
When we left the cabin this morning with a full battery (47 mile indicated range), the car began to charge the battery through regenerative braking. After about 4 miles, the car indicated 60 miles of battery range. After 8 miles of driving in Low, I noticed a surge in acceleration (or a decrease in regenerative braking) and the car's speed began to pick up with very little indicated charging. Apparently, the battery had absorbed everything that it could take. After that, the only braking I had was conventional friction braking. I did notice that the pie chart milage indicator on the energy efficiency pane of the center stack display was showing "gas" miles with 0.00 gal of gas used. The gas engine had not come on. Apparently, the blue wedge that has a legend indicating "gasoline" miles really means "inefficient" miles. That indicator crept upward the more that I used the brakes up to 4.6 miles. This is one way to tell when friction brakes are being used while in electric only mode. We got to the bottom of the hill with still 60 miles indicated on the battery. As it turned out, I drove 53 miles from that point or 75.3 miles total of electric range. This is a record for me, my best ever on the battery before was the 49 miles that I got on the way to the cabin. To get the rest of the way home, it burned another 0.66 gallons of gasoline for a total round drip consumption of just 3 gallons for a total indicated distance of 204.6 miles (102.2 indicated there, 102.4 indicated on the way back via the same route but a slightly different path due to freeway interchange ramp differences in the different directions).
When the battery is fully depleted, the car normally indicates that 10.2 kWh of electrical energy was derived from the battery. This time, it indicated 11 kWh. This implies that up until the time that the car refused to accept any more regenerative braking energy, the battery charged up about 8% above the point that it will charge from grid power. This is a consistent range increase between the 49 miles going up and the 53 miles I got after reaching the "flat" (junction of hwy 330 and I-210) on the way down.
The Volt is close in concept to a heavy, or plug in, hybrid. There is some argument as to whether it is a "hybrid" or not, but for all practical purposes, it is close enough. A heavy hybrid does not fully recharge it's own battery, as a light hybrid does, and needs to be charged from grid electrical power to provide it's best operating efficiency. In my case, that would be equivalent to about 100 mpg (on a cost equivalent basis) if I stay in the all electric range of the car, or about 35 to 45 miles per day. Electricity carries 2 to 6 times the energy per dollar as compared to gasoline. The actual factor depends on local electrical power rates and the local cost of gasoline. In my case, the best electricity rate I can get is 25% the cost of gasoline. However without some changes to the default household rate, the cost of electric power is nearly the cost of gasoline. My current rate is based on SCE's Tier 3 with part of the charge at a Tier 4 rate for the Schedule D rate plan (the standard plan) at an average of $0.27/kWh. There are two other plans tailored for charging an electric vehicle overnight instead of during the daytime that can provide lower rates, down to $0.10/kWh.
The Volt can charge at either 110 VAC or 220 VAC. The difference is in the charger. The car comes with a 110 VAC charge adaptor and cable which can fully charge a depleted battery in 10 hours. At 220 VAC, the charge time is 3.5 to 4 hours but this takes an aftermarket charger and cable. Amazon has them listed for about $1000. I don't have any 220 VAC wiring anywhere in my house outside of the main breaker box. Those chargers are appropriate for all electric vehicles which will take all night to charge even with a high rate charger or for electric rate plans that offer a night time window lower than a normal off peak rate. Note that the real charger is inside the car itself. The external device called a "charger" is really a charge adaptor.
The 110 VAC charger cable is stored in the rear compartment of the car. The cable reaches 20' and should not be used with extension cords. A competent electrician can determine if there is sufficient voltage where ever the charger is plugged in to safely provide the 12 amps that the car needs to charge.
If there is not sufficient AC voltage to charge the car at the full 12 amps, the charger will drop back to 8 amps. If the charger is still unhappy, it will turn on a red light on the charger and shut off, leaving the car uncharged. The car also defaults to an 8 amp charge every time it is driven so that it must be reset to the 12 amp rate from the center console screen every time it is charged. This is a pain. Without doing this, the car takes 16 hours to fully charge.
My electric utility, Southern California Edison, offers a tiered rate plan tailored for electric cars or users that can shift their loads away from peak hours on weekdays.
The California Public Utilities Commission sets the rates for the local electric monopolies. The standard rate schedule is based on a baseline allocation that depends on the user's location and if they have an all electric home or a combination of gas and electricity. My home uses both electricity and gas. My baseline allocation is 9.6 kWh/day in winter (Oct-May) and 9.2 kWh/day for summer (Jun-Sep). The Tier 1 allocation is up to 100% of the allocation, Tier 2 is up to 130%, Tier 3 is up to 200%, Tier 4 is up to 300% and Tier 5 is above 300%. My typical usage even without the car barely pushes into Tier 3. Charging the car would push it well into the higher rates depending on how often the car is charged. At the highest rates, electric energy used by the car would cost as much as premium gasoline.
|Tier 1 Rate||Tier 2 Rate||Tier 3 Rate||Tier 4 Rate||Tier 5 Rate|
I have measured the total power consumed by one recharge from 110 VAC using a Kill-A-Watt. The car consumed 13.34 kWh for the total charge cycle. At current domestic rates in Tiers 3 and 4, that would cost $3.48 per full charge, nearly the same as a gallon of premium gas costs in early 2013. A full charge provides roughly the same range as a gallon of gas. Note that the battery only provides 10.2 kWh after a full charge. The difference is due to inefficiencies in charging and discharging and that the car regulates the temperature of the battery during charging. In some cases, the car will turn on the electric air conditioner in the car and chill the battery (which is liquid cooled/heated) to control it's temperature. If it is cold enough outside, the car might also have to heat the battery. In extreme temperatures during charging, the car may consume more than 13.4 kWh for a full charge.
Southern California Edison (SCE) offers a rate plan, called TOU-D-TEV, for users that can shift the period of their highest power consumption away from the summer peak usage hours of 10 AM to 6 PM. This plan uses the same power meter that meters the whole house. Basically, I can get a lower rate per kWh if I recharge at night, shift laundry and dish washing to after 6 PM on weekdays and set my furnaces to not run between 10 AM and 6 PM (which is the way that they are set already). The summer and winter rates (4 months of summer, 8 months of winter) for this plan are quite different so that during the "winter" when the furnaces are likely to run, the rate penalty of going into the "peak" rate is not too severe. A forced air gas furnace consumes quite a bit of electric power to run the blower. The lower overnight rate is balanced by a somewhat higher rate during the peak hours. If the power consumption falls beyond 130% of the base allocation (called Level 1 which is the combination of Tiers 1 and 2 in the Schedule D plan) then the suummer daytime rate goes WAY up to $0.60 per kWh during peak summer hours but only to $0.27/kWh during the peak winter hours. Level 2 is a combination of the Schedule D Tiers 3, 4, and 5. The power companies want to shift summer load from the day, where lots of power is used, to the night where the power demand is lower and will provide incentives to the users to do that. They avoid new capital investment in generation and distribution infrastructure by shifting summer load from the day to the night. My electric meter is smart enough to know the rate structure so that it can tell when I am using power. I'd basically be paying $0.11 or $0.17/kWh for 6 hours worth at the lowest, midnight to 6 AM period, and $0.25/kWh for 4 hours at the mid rate for a total of $2.81/full charge. If I recharge the car when it is only half discharged, then I can stay at the lower rate and a full charge (two nights) would cost $2.16.
|SCE TOU-D-TEV Rate Schedule
|Level 1 Rate||Level 2 Rate||Level 1 Rate||Level 2 Rate|
10 AM to 6 PM weekdays
All other times
Midnight to 6 AM every day
Another way to do this is to program the car to charge during the off peak periods only. This is a 6 hour window between midnight and 6 AM. If the car is fully discharged, then it will get only a 60% charge for use the next day. I likely won't use all of that the next day so I can put it on charge the next night too. Eventually, it will find it's way to a full charge but it will have enough to drive in full electric mode most days. Doing it this way is the same as the two-pass charge method described before at $2.16 for the equivalent of a full charge but it is automatically handled by the computer in the car. I don't have to manage the charging except to plug it in before midnight.
I can even get a lower rate plan, TOU-EV-1, customized for charging electric cars, if I install a 2nd power meter and breaker panel just for the car. Then the rate is $0.12/kWh from 9 PM to noon year round or $1.60/full charge. However, I would have to make the capital investment in a new power box and wiring. SCE will provide the meter, but I have to provide a breaker box to install the meter in and any wiring to the charging outlet. My initial investigation into do this has not yielded good results. The quoted cost of the electrical work, about $1500, results in a payback period about 10 years depending on how often I charge the car.
|SCE TOU-EV-1 Rate Schedule
Noon-9 PM every day
9 PM-noon every day
The car has charging modes that delay charging until the charge can fit before a defined departure time to try to keep most of the charging time in the lower rate periods. This is programmable in the car for each day of the week. Further, the car can be programmed to be aware of rate changes during the day, up to 5 periods of High, Mid or Low rates for each 24 hour period. Summer and winter rates can also be programmed. This allows the car to decide when to start and stop charging to achieve the lowest charging cost consistent with it being ready to go at some departure time for each day of the week. This programability covers the whole range of the rate tables provided by SCE. The car does not know the absolute power rates but it does know the difference between peak rates, off peak rates and "super" off peak rates.
After fully characterizing virtually every electrical load in the house, I have found that I can practically make only a small improvement in total power consumption without moving into a cave somewhere. I had already plucked the low hanging fruit by getting rid of incandescent lighting and replacing my refrigerator. The rest of any possible improvement will be only about 2 kWh/day while the car consumes 13.5 kWh for every full charge. I could charge the car once a week and get back to where I am now in terms of my electrical power usage. If I charged the car every day and didn't consume electricity for anything else, I would still be at 130% of my baseline allocation. Therefore I have to change my rate schedule to reduce the cost of electricity. The dual meter option is not cost effective because the capital expense of adding the 2nd meter is too high. However, I have found another way.
The US government Department of Energy (DOE) has a project called the EV Project. The project seeks to gather information on the charging habits of electric car users and evaluate the impacts of such additional electrical load. To this end, they need data and they are willing to pay, after a fashion, to get it. I have enrolled in the program. The deal is that they supply a free 240 v charger if I agree to allow it to connect to my WiFi network and return charging data until December 2013 when the project ends. I get to keep the charger at the end of the project. Further, if electrical work is needed to accommodate the charger, they will subsidize such work up to $400. Electricians don't come cheap. Installation of the charger and service for 3 years will still cost me about $500 even after the rebate. The advantage to me is that I get about $2000 of parts and services for $500. Also, the car will fully charge within the 6 hour "super" off peak rate every night. At that point, a full charge, good for 40 to 47 miles costs me $1.48 to $2.14 depending on if I have moved into Level 2 in any given month. This is about half the cost of the gasoline that would take me about the same distance. The payback is about 4 years. The only better rate is $0.05/kWh cheaper and then only during the last 1/3 of the month after I have passed into Level 2, but that would cost me about $1500 more to achieve. The payback in that case would be about 15 years more.
The electricians came and went today leaving behind a Blink charger on the outside wall of my garage. The job did cost just over $500 and it all worked. Now, the car will charge in 4 hours from dead flat which is within the 6 hour "super" off peak rate. This rate is $0.11/kWh for about the first 20 days or so of a billing month and $0.17/kWh for the remaining part of the billing month. The rate difference is when I transition from the Level 1 allocation to a Level 2 allocation.
The actual cost to charge the car is more complicated than it looks. At the TOU-D-TEV rate during any given month, part of the cost of charging the car occurs in Level 1 and part in Level 2. However, if I consider that I could get a similar rate, TOU-D-T, without the car then I can compare what the car does to me. The TOU-D-T rate is the same as TOU-D-TEV but it doesn't have the "super" off peak rate.
Without the car, and via some changes in my household power consumption, I estimate that my baseline consumption will pretty much fill Level 1 of the TOU-D-TEV rate. Therefore, everything I add because of the car is at the Level 2 rates. My daily household cost will be about $1.70 in the summer and $1.44 in the winter. Since winter lasts twice as long as summer, the weighted average is about $1.52 per day for the whole year. This is opposed to the daily cost of $1.68 per day on the Schedule D rate. This also assumes that I don't shift any household load out of the peak period, which I will do anyway. Changing to the Time of Use schedule results in only a little savings by itself.
Adding the car complicates things a little because for the last 1/3 of each month, the car and household will be at the Level 2 rates. For the first 20 days or so, the car will charge at $0.11/kWh and for the last 10 days at $0.17/kWh. The weighted average is $0.13/kWh, or almost the same rate as the TOU-1-EV (dual meter) rate at $1.60 per full charge. The off peak rates do not change with season.
Then the household rate increases a little because 1/3 of the household usage will also be pushed into Level 2 and the peak rates of $0.60/kWh in the summer and $0.27/kWh in the winter apply. My best guess is that of my total household usage not including the car (which will never be charged at other than the super off peak rate), that 2 kWh/day will be at the peak rates and the remaining 10 or 11 kWh/day will be split between the off peak and super off peak rates. I am guessing that 2 kWh/day will be in the super off peak time and the remaining 8 kWh/day will be in the off peak rates. For the last 1/3 of the month, my rate will be $3.32/day summer and $2.68/day winter. Annualized, the cost of pushing 1/3 of my household power into Level 2 adds $162 to my power bill. In effect, this adds about $0.90 to every charge of the car, so instead of costing me just $1.60, it costs $2.50. This is still less than 1/2 of the cost of gasoline.
The real swing factor in the Time of Use rates is the summer Level 2 rate. It is really important to reduce the exposure to the peak summer rates.
Note that if I didn't use the time of use plan and just paid the regular rate for power, the car would cost $3.62 to charge. Going to the time of use rate results in a payback of 2.5 years for the $500 installation charge assuming that I charge the car every other day.
The dual meter rate would cost a straight $1.60 per charge but at another large capital expense to install a 2nd panel and meter. I am figuring that it would cost another $1000 to $1500 so that the payback of avoiding the $0.90 penalty of the time of use rate would be about 6 to 9 years.
If I charged the car 5 days a week, the paybacks would get correspondingly shorter.
The charge plug for the car is an industry standard design. It can be used in the rain. The plug is alarmed such that if the car is locked, removal of the charge plug will sound the car's horn, flash the lights and immobilize the car. If the car is set to a charge schedule that would not normally start when the cable is plugged into the car, it can be set to start charging immediately if the cable is plugged in, removed for less than 5 seconds and then plugged in again. This allows immediate override of the charging schedule without having to change the schedule.
Since the Blink charger has some smarts built in, I can also set the car to charge immediately when connected, but set the Blink to not provide any power until midnight. This eliminates all issues about when to plug it in. It is locked at the super off peak rate when running on the 240 volt charger but the car will charge immediately on the 120 volt charger that I can use at my cabin.
My car is the base model with no factory or dealer installed options. There aren't many options to choose from. You can add only about 10% to the MSRP of the car by loading it with options. The upgraded interiors include leather and heated seats. There is an optional satnav system and higher performance radio. There are also an optional rear, forward and side view cameras. Check out the Chevrolet web site to get the details on factory options.
Beware of dealer installed options. These are a major profit center for dealers and they want to push as many of those out as they can. They are rarely worth the money that the dealers charge. If you want fancier alloy wheels than the ones that come on the base model, you can get them for much less on the aftermarket and still sell the wheels that came on the car.
The Volt is a comfortable car in my opinion. The base model has most of the creature comforts of a well equipped car.
The car rides smoothly but the suspension travel is quite limited due to the low stance of the car. Watch those dips. The Volt has the known tendency to scrape the rubber aero-dam under the front bumper on dips, especially if there is any front end suspension compression at all. Mine is covered in scrape marks already. There is only abut 4" of clearance to the dam on a flat surface with no suspension compression.
The seats are not electrically adjustable. The seat can move forward and back by a generous amount, although there is hardly any legroom for a back seat passenger with a front seat slid all the way back. The seat height and back angle are adjustable. The headrest height is adjustable and actually works better in supporting my head than any other car I have driven. This includes lots of generic rental cars.
The rear seats are another story. With the driver's seat in a position that is comfortable for me, there is only 6" between the back of the front seat and the edge of the back seat. I cannot get in the back seat like that. There is a little hope on the passenger side with my wife's seat in her preferred position, but it is still tight. Don't count on getting four adults in the Volt.
The side mirrors are electrically adjustable and the rear window is electrically defrosted. There is an optional rear view mirror automatic anti-glare adjustment, but this isn't on the base model. The base model uses the conventional click lever. Visibility is fair even without the optional cameras. However, the forward posts ("A" pillars) are quite large and do block some of the driver's view forward to the right and left of the car. Anybody with normal neck mobility will not have serious troubles with visibility.
The steering wheel and steering column controls (turn signals, cruise control, radio control, Bluetooth cell phone control, headlights, and wiper controls) are all pretty conventional. The steering wheel itself telescopes and is adjustable for height. There is also a button on the turn signal that beeps the horn quickly to warn pedestrians. The car really is quiet enough so that, in a normal urban noise environment, pedestrians do not hear the car coming.
The electric windows controls are conventionally placed but the lock/unlock buttons for the doors are on the center stack instead of on the doors themselves.
Most of the rest of the controls are on the center "stack" topped with an LCD status touch screen. The panel shows either radio functions, environmental control status, system charging status, or hybrid drive train status. The whole stack is one assembly so that if part of it craps out, it is likely that the whole stack will need to be replaced at considerable expense. The stack uses mostly touch sensitive buttons.
Climate controls are also on the stack. There are three climate control modes as opposed to two in most cars. Usually, there is an A/C on/off button, you either get chilled air or just a fan blowing outside or recirculated air. The Volt has to run it's A/C from the battery so that there is an "Eco" mode too. This one consumes less power, so it probably cools less too. Most cars extract some of the waste heat from the engine to heat the car. Since the engine is not supposed to run most of the time, this won't work on the Volt. Electric heat is used instead. There is a separate cooling system for the electrical equipment and battery. Aggressive use of either heat or A/C can decrease the battery range by half. The optional heated seats use less power than heating the whole cabin, but in SoCal, heat isn't much needed anyway. There have been some comments that even at full heat, the Volt heater doesn't keep up with really cold climates.
The milage report screen on the center stack resets at every charge. It shows the percentage of time driven on electric vs gas and the milage since the last charge. One item that is not reset is the lifetime milage. Mine isn't very high right now (in the 60's) because most of the miles represented were on gas on the drive from LA to Vallejo and back.
Programming the charge parameters (special hours or rates) is also done on the center stack LCD screen. Charge parameters can also be programmed at MyVolt.com or with the OnStar Remote app for iOS or Android.
The car shaped body is really a hatch back. Hatchbacks are materially easier to load with cargo than a trunk. This is important to me. Further, the rear seats can be folded down individually to provide more cargo area at the loss of passenger seating capacity. There is quite a bit of cargo room as compared to most sedans.
A cloth screen came with the car. It fits on some hooks and shields the contents of the storage area behind the rear seats from view. None of the windows are tinted so that without a screen it is easy to look down through the rear window to view the contents being carried behind the rear seats.
Since the battery is located in a compartment that runs the length of the cabin, something has to be done on top of this area as it can't be used for seating. Between the front seats is a compartment that has a 12 volt cigarette lighter style power jack, a USB connector and an audio line-in minijack. I have a plug in AC inverter and a retractable USB cable plugged in now. I can charge my cell phone or iPod in there. There are a couple of cable passages molded in the console to allow wires to exit the compartment with the lid closed. This is pretty handy. There are a couple of cup holders right in front of the compartment cover.
There is also a console between the rear seats which are folded down in this photo. It has another power jack, some cup holders and a bin to hold small stuff.
There is yet another compartment on the dash with a 3rd power jack. I assume that dash mounted devices, such as a stand alone navigation unit or cell phone dock/holder would be connected there. The car has Bluetooth connectivity for hands free phone operation although my phone is so basic that it doesn't even have Bluetooth.
Since I made the initial evaluation of visibility, I managed in strain a muscle in my neck making it harder to turn my head fully to the side. Now the "B" pillar (the one between the doors) does a good job of blocking my view to the rear quarters and the "C" pillar does the rest of the job. I have to be very careful while backing and making lane changes to make absolutely sure that no obstructions are present. The optional mirror mounted side view cameras could help a lot BUT they display on the center stack which is just where a driver is NOT used to looking to see what is behind. Since I don't have them, I cannot know how well that they work. However, for drivers with limited neck mobility, they may be helpful.
The base Volt comes equipped with OnStar, GM's radio communications technology. There is a blue button on the roof panel which accesses OnStar. I am not yet sure what all OnStar does, but apparently GM uses OnStar to get telemetry back from the vehicle. OnStar also can detect airbag deployment and automatically contact the car to offer aid. OnStar isn't a free service, although my car came with 1 year of OnStar service. Otherwise, it is $20/mo. Next to the blue OnStar button is a phone button. This activates a hands free in-car phone. I asked the salesman at the car dealer what network it uses. He said that it GM's own network and it will work where other networks do not. He indicated that it was a satellite link but I found that unlikely. Up at the top of the windshield next to the mount for the rear view mirror, there is a square plastic box that likely contains a through the windshield antenna of some kind. However, the manual indicates that OnStar will only work in areas were OnStar has a agreement with cellular radio providers so this implies that OnStar just uses one or more cell radio networks.
After using the hands free phone in some odd places, I can conclude that at the very least, it uses Verizon's network. My cabin has absolutely zero GSM coverage from any carrier but the phone works fine there.
The button to the left of the OnStar button activates the in car phone. The red one with the white cross is to summon emergency help. I gather that the car has GPS and will report the car position to OnStar, but without the navigation option it won't display the car's position. It is possible to get turn by turn directions via OnStar but without a map display unless the optional satnav package is installed.
Before I took delivery of the car, the salesman had us go through a orientation call to OnStar and we bought some voice minutes, $10 for 300 minutes which is pretty cheap as pre-pay minutes go. However, after the $240/year OnStar basic service is added on, those minutes can look pretty expensive compared to other pre-paid cell providers. Due to an error at our end, our orientation call was interrupted so the salesman finished it as we were nearly done anyway. However, nobody told us what the phone number of the car was. I used the in-car phone to dial my cell phone and then hung up the call after it rang. I then extracted the phone number from my missed call list and dialed it back. It connected. Later, I found that the number is reported in one of the OnStar menus. I also found an email from OnStar that had been identified as junk mail on my computer that had the phone number in it.
The other functions on that panel are to control the left and right reading lamps and to manually activate the dome light. The dome light does a good job of illuminating the cabin.
The visible warning light is for the rear seat airbags which are likely disabled because the seats are folded down.
The other three small buttons are some kind of emulator for typical garage door and security gate remote controls. I have no clue how they are programmed as I have no need for that function. There is simply no way that I could get a car into my garage.
Since the vehicle is "connected" there must be a way to do something with that. As a matter of fact, "there is an app for that." GM has published apps for both iOS and Android. This screen is from the iOS app that remotely shows the state of the battery and the power consumption status.
There is also a web page that does pretty much the same thing as the smartphone app.
Another screen shows the state of the gas tank and the latest gas consumption status.
The vehicle also has tire pressure sensors. I see that three of them are a little low, but I should find some nitrogen to pump them back up.
This screen is the most interesting. I can use the app to lock and unlock the car, start it up but not drive it, turn it off and to blow the horn in case I can't find it in a parking lot. The access to the data is protected by a username and password and this screen is further protected by a PIN.
The real utility here is that if I remotely start it, the climate control system comes on and the vehicle will reach a comfortable interior temperature to be ready for me to drive away. If the car is not plugged in at the time, it will remote start from battery power. If it is plugged in to charge at the time, it will use grid power to provide the energy it takes to heat or cool the cabin. The car will turn on it's parking lamps and various pumps and blowers will cycle on and off at times. It MAY also start the gasoline engine so that remote start should not be used without adequate ventilation. After all the buzzing and whirring stopped, the exterior lamps extinguished and the car was charging again trying to add 2 miles back to the range. Apparently, the remote start process consumes more power than is available from 120 VAC and it hits the battery too.
The power consumed during a remote start is non-trivial. On the 120 volt charger, the car drew a full 8 amps (about 950 W) during the remote start operation for a total of 0.8 kWh drawn over a period of 50 minutes. A remote start while plugged in allows the car to stabilize without detracting from it's electric driving range. Remote start on battery power doesn't make a lot of sense unless you really don't want to get into a hot or cold car or you don't care about the lost range because you weren't going to use the full electric range anyway.
Now that I have described the car pretty fully based on my observations as a new Volt owner, it's time to describe the experience of just driving it.
In the last three weeks since I bought the car, I hadn't driven the Yukon at all except to move it once in a while so that it didn't get towed. My city has a 72 hour limit for vehicles parked on the street.
Today, I drove the Yukon for about 12 miles to put a few miles on it, get the lubricants splatter about inside, charge up the battery and put some gas ($85 worth and it still had a quarter tank to go) in it. I observed these things.
Noise caught my attention right away. The Yukon engine noise is actually pretty loud. The Volt makes very little noise at all. Tire noise seemed less on the Yukon, but suspension noise as I hit bumps in the road seemed to be much louder in the Yukon. It turns out that the road noise on the Volt seemed louder than the Yukon but that was just because the engine noise on the Yukon was drowning out the road noise. Overall, the Volt has considerably lower total noise, what I do hear is just from different sources than in the Yukon.
Visibility in the Yukon is better. The vehicle sits much higher and I can see right over all other passenger cars. The side view mirrors are larger and give me a better view behind. The Yukon has cargo doors. These open sideways. There is a vertical post in the center that is not wide enough to obscure a car, but can obscure a motorcycle if it is far enough back. The Volt has a horizontal bar that divides the large hatchback window with a smaller window below. At a sufficient distance, a car can completely hide behind this bar.
Braking has to be done more aggressively as well in the Yukon. Very light pressure on the brake pedal will slow the Volt much more quickly that the same pressure on the Yukon's brake pedal. I found myself driving the Volt in the "Low" mode to get more aggressive regenerative braking while driving in the city and hardly using the brake pedal at all except below 5 mph to bring the car to a complete stop. This is not really possible in the Yukon except by downshifting which one would not normally due with an automatic transmission.
Coasting caught me off guard in the Yukon. The Volt has a small amount of regenerative braking when coasting, even in the Drive mode, with no pressure on the accelerator pedal. The deceleration is not enough to really notice and it feels like the car is free coasting. However, in the Yukon, there is much less drag and I found myself closing on cars in front faster than I expected. I had to get used to dragging the brakes of the Yukon a little to prevent closing on another car too quickly. When the Volt is operated in Low gear, the brake lights do not operate while the regenerative braking is slowing the car considerably. Drivers behind are continually surprised as they run up on the rear of my car as I am slowing without brake lights showing. I feel that Chevrolet has to change this somehow, brakes are brakes whether or not they are the result of friction of regeneration. The brakes lights should show to indicate a greater than "normal" deceleration rate.
Climate control in the Volt is pretty much the same as in a regular car when it is turned on. However, while I was testing to see what kind of milage I could get on electric power, I had the whole climate control system turned off much of the time. It is winter in SoCal right now so A/C is not necessary. Note that in SoCal near the beach, daytime winter temperatures below 60°F are uncommon so that "cold" is a relative term. When summer comes around I'll see how much I need the A/C. For reference, last summer, I did not often catch the temperature at my house above 85°F, and even then for just a few days. However, during summer, the temperature can rise 1°F per mile inland from the beach up to about a 30°F increase so that A/C would be desirable when driving far from home.
Wind noise is an issue with the windows rolled down. The geometry of the car results in a pulsation sound that is quite annoying if the car is driven with the windows down. Also, the disturbance in airflow around the car when the windows are down can materially increase the wind drag on the car. Chevrolet recommends to drive with the windows closed. The driver's side windows does not allow a partially open condition. It either opens or closes all the way. The other three windows can be stopped in a partially open condition.
Door Locks operate differently than any other car I have come across. There is a button on the outside of each door that, when pressed, will unlock the car provided that a key fob is within 3 feet of the car. The button on the driver's side will unlock the driver's door. A second press within 5 seconds unlocks the other three doors. Pressing the button on one of the other doors unlocks all five doors. The button on the hatchback will unlock the hatchback. It is not necessary to even take the key fob out of your pocket to unlock, turn on, drive the car or lock it again.
The Locking Gas Filler Door has to be unlatched from inside the car (button on the driver's side door) by holding the button for more than one second. Then the door over the gas cap is unlatched but it must still be opened manually. There is another button on the door (and also on the key fob) to open the cover over the charge jack.
The gas tank is sealed and kept pressurized to prevent moisture ingression into the gasoline. Water that is absorbed in gasoline sinks to the bottom of the tank and accumulates there. That is where the tank is drained so that small amounts that accumulate in the gas in a conventional car are drawn through the engine and discarded in the exhaust without serious problems. The gasoline can sit in the Volt's tank for a long time and sufficient water can accumulate there to stall the engine if the car has been run in electric mode for long enough (many weeks). The combined effect of the sealed and pressurized tank and the Fuel Maintenance Mode mitigates the spoilage of fuel by water.
The turning radius is pretty good. I can almost do a full U turn in a residential street. By encroaching on a driveway on either side by a few inches, I can make a full U turn. By contrast, the Yukon doesn't quite make it to fully perpendicular to the curb when I try to turn it in the same street.
Handling is good. The car has limited suspension travel and rides a little stiffly, but it aslo corners nearly flat. I am not a sport driver and I haven't really thrown it around, but it clearly sticks to the road well with very little sway.
California highway 330 is a winding mountain road that climbs from Highland CA to Running Springs CA. That climb is about 4500 feet with the center 2/3 of it at a nearly constant grade that I estimate at about 7%. The folks that live on this mountain know this road pretty well and many of them drive it pretty fast. My old van was lucky to make the grade in 2nd gear at 35 to 40 mph. The Yukon can take the climb faster, but many of the turns are pretty dicy for a truck at 50 mph. It just doesn't handle all that well. The Volt was right at home on this road. It tracked very well and even with a fully depleted battery, it ran up the grade as fast as I cared to go, up to 50 mph in spots, slower where the turns were tighter. The engine was indeed running at nearly it's full power level, but it had enough power to make the climb and cornered well enough to do it at the speed limit of 50 mph.
Distractions are an issue. Both displays provide lots of information useful to the driver and the center stack display can be switched between many modes. When the driver operates the center stack touch screen it takes the driver's attention away from the road. This is not good but it is probably an issue with any car with electronic displays.
The speedometer is a bit of a mystery. First off, it seems to be dead accurate as compared my wife's iPad using GPS which can also measure speed. I strongly doubt that a traditional pickoff from the drive train could be that accurate. Further, I found a forum discussion on the internet were this was discussed. The original poster had also observed that the speedometer was exactly the same as his Tom-Tom. Several other posters had observed the same thing. There cannot be several cars out there that track GPS that accurately without using GPS to measure speed. My vote is for a GPS assisted speedometer that can run in a conventional manner until a GPS signal is acquired and then the speedometer and odometer get their data from GPS.
Further, the miles traveled reports are presented with a precision of 0.1 mile. This doesn't imply accuracy, but it does imply that the GM engineers think that it MIGHT be that accurate and the only way to get that kind of accuracy is by using GPS. The gasoline consumption is presented with a precision of 0.01 gallon but this is an illusion as it increments in 0.03 to 0.05 gallon steps.
The rest of the normal driving experience between a Volt and a "regular" car is not enough different to really comment about.
This page has been accessed times since 10 Jan 13
© 2013 George Schreyer
Created 10 Jan 13
Last Updated March 31, 2013