Chevy Volt watts per mile vs. Model S

Chevy Volt watts per mile vs. Model S

I presently own a 2012 Volt and have an order in for a Model S. I've been curious about the range people are getting in the Model S. In my Volt I can routinely get 41 or 42 miles from the 9.7Kw of battery it lets me use which means 230 watts per mile. Obviously this range is this time of year which means nice warm weather which helps. Getting this range doesn't feel like I am hypermiling or babying it. I run the AC on Eco mode, I run it on normal not sport (but can easily beat 300 watts per mile even in sport mode). I realize the Model S is a much larger and more powerful car, but if you got the same efficiency from an 85Kw Model S you could go 369 miles. It seems like 300 miles on a range charge should be pretty easily doable and even possible on a 90% charge. You might even be able to get the EPA estimated 265 out of an 80% charge. Any Model S owners out there that are prior Volt owners have any experience to share?

carlk | September 7, 2013

It's very hard to get watts per mile for Volt since it's a plug in hybrid and not pure EV. I have heard from some auto test reviews the gasoline engine does turn on when additional acceleration is needed even during the initial 40 miles EV mode.

negarholger | September 7, 2013

Over at Tesla Motor Clib there is a thread lifetime Wh per mile., that gives a good range what to expect. My lifetime average for 6k miles is 335 Wh / m... but that includes a lot of city, on longer trips I can easily get it under 300 Wh / m driving 72-75 m/hr

bonaire | September 7, 2013

Carlk, no I am sorry, you are wrong. Volt does not use the engine at all for added acceleration. It can use the battery if you floor it from a stop to its max speed of 101 mph.

It only uses gas when the battery charge reaches low state of charge, you enable mountain mode and SOC drops to 13-15 miles remaining or a 2013/2014 model uses its Hold mode (i will leave that to you to google).

Volt Wh / mile depends on how you drive. Same as tesla. Once up to speed, Wh/mile is similar. The speed you drive, ambient temps and a lot of other inputs alter the Wh/mile. I estimate on average, removing pre 5.0 firmware vampire drain, that a normal tesla usage is about 5%-10% more than a Volt. More on board electronics such as the sound system and dash electronics are part of that. The higher weight of the model S also is part of that.

Does it really matter? Yea, I also believe that if you extrapolate out the Volt's 10.4 to 10.8 kWh of usable SOC, could say have a 50kWh system give 200 miles of range but that would mean carrying a 60kWh battery to do that in a Volt. I suspect that the range charge of a Tesla uses far more of the battery State of Charge than Volt uses with the 10.4 to 10.8 out of the physical 16-16.5 capacity.

bonaire | September 7, 2013

bTw, i also get well over 40 miles of range, and in summer, my morning commute to NJ gives me 50 miles electric range. I do lose 600 feet of elevation but all the miles are highway between 60-65 mph.

simplesolarinc | September 7, 2013

I've gone to a range of around 300 miles using slightly below 300 watt/hr. But it was driving like a grandpa conserving range avg 40-55mph on the freeway and drafting behind trucks.

No fun at all. I prefer driving at 400-500wh/mi and putting a smile on my face.

Motobones | September 7, 2013

I also realized after I posted that all 85kw are probably not useable. It would be interesting to know how much of the battery capacity you can use before you hit reserve battery life, someone on this forum probably knows. In the Volt since you have the gas engine you can use all the battery they allow I'm guessing Tesla has certain parameters on battery usage to preserve long term battery life.

Blueshift | September 7, 2013

Some notes on units:

k = kilo = SI unit for 1000 (always lower case)
W = watt = energy use per time (always upper case)
h = hour

Wh = (energy per time) * (time) = energy
kWh = (energy per time) * (time) = 1000 more energy

Rember W is a rate of enery usage and Wh is total energy. So it is correct to talk about batter capacity in turms of Wh or kWh, but not W or kW.

Water analogy:

W is like gallons/second.
Wh is like number of gallons.

Blueshift | September 7, 2013

turms = terms (this forum could really use an edit capability)

Zero EV | September 7, 2013

I've got a little over 5000 miles on my S85 now. It's a daily driver for me at about 150-160 miles per day. Most of this is interstate between 70-75mph. I am averaging 305 Wh/m. I don't drive like a grandpa, but I'm not overly aggressive with it either.

I routinely charge to 90% ... start out at a "Rated" range of 237 and return home with about 75 miles remaining.

It's summer here now with an ambient between 80 and 90 ... and I don't find much difference between windows up/down, A/C on/off, etc.


Robert Hodgen | September 7, 2013

We have a Volt and a Tesla. We easily get 200 wh per mile around town in the Volt (5 mills per kWh) and struggle to get under 330?wh per mile (3 miles per kWh) in the Tesla. I think the difference is the additional 1000 pounds the Tesla weights. On the highway above 65 mph, I think the Tesla might be a bit more efficient. Speed doesn't seem to have as dramatic an effect with the Tesla as the Volt. It's accelerating the extra mass in the Tesla that hurts it in stop and go.

Dcp9142 | September 7, 2013

My Tesla, on same route as my Volt gives me 260 Wh/mi where 2011 Volt range was 46 mi. Hope that helps.

Tesla-David | September 7, 2013

I have averaged 311 W/Mile since my Tesla was delivered (6,300 miles) and have averaged 288 W/mile over last 3,000 miles. Most of these miles are from in city driving, commuting to and from work 35 miles round trip @ 30-55 mph. From my perspective I find it very easy to beat the 300 W/mile rated range. It is wholly dependent on the way one drives, heavy foot or not. I do not drive my car hard but do not baby it either. I had an opportunity to drive a P85+ for 1.5 days while my S85 was being serviced, and had no problem getting under 300 W/mile.

carlk | September 7, 2013

@bonaire looks you're right. My bad.

@Motobones That should not be a surprise at all. Comparing Civic and S550 would get you even more drastic differences.

cfOH | September 7, 2013

No, the Model S, being a bigger, heavier car, does use more juice per mile than the Volt.

But, how does the Volt compare on Watt-hours per mile per passenger?

Volt: 230 Wh/mi / 4 passengers = 57.5 Wh/mi/pass

Model S: 320 Wh/mi / 7 passengers = 45.7 Wh/mi/pass

Of course, I suspect the Leaf does even better than either of these cars on this metric.

shs | September 7, 2013

The other metric that can be compared is MPGe where the Volt is 98 and the MS 60 is 95. Pretty similar mileage given the difference in performance and carrying capacity!

soma | September 7, 2013

Volt weighs 3,781 lb, Tesla 4,647 lb, a good 20% extra weight.

bonaire | September 7, 2013

CfOH, sure. Go person-efficiency on it :)

Most folks drive alone to work, so the idea of using energy per person mileage is not a typical situation.

What about a volt pulling a small trailer full of circus clowns?

cfOH | September 7, 2013

@bonaire: Ah, very clever are you?

I see your tiny trailer of circus clowns and raise you a frunkful of midgets!

DouglasR | September 7, 2013

One interesting claim regarding the Volt: my brother says that the on board generator on his Volt will charge the battery at about 54 kW, the same rate as the high speed DC (CHAdeMO) chargers for the Leaf, etc. He says he needs to put the Volt in "mountain mode" to do this. I don't vouch for the reliability of this claim, and I don't contend that it is an efficient way to charge the battery.

Dr. Bob Reinke | September 7, 2013

Couple of things from our experience my weekly commute is about 187 miles each way. When I can I try to make the drive when the wind is favorable. At 70 to 75 it is very easy for us to make it each way on a standard charge with 50 to 80 miles range left. Most of the trip is at consumption of 260W to 300W with AC on. 290W to 320W with the heat on. Wish that Tesla had an inexpensive Air Speed meter. That would help gageing the projected juice use, and would give a better reading on how much drafting is helping range.

My brother has a Volt and lives on a busy four lane rural road. He says, and I have been with him when it happens, When he backs out of his drive and guns it to get out of the way of traffic, the ICE always starts, even just off the battery charger. Then he has to stop the Volt to get the ICE to shut-down.

Incidentally, I don't want Tesla to make the touch screen directional responsive. Then I would have to be driving up all the time. At least now, I'm driving down and can save juice half the time-------

bonaire | September 8, 2013

Dr. Bob - no that is not how it works. I actually don't believe this is happening and you are making this up. I've studied the Volt for years, we have heard from Volt engineers regarding this and what you explain does not happen. The electric motors always draw power from the HV battery. The engine cannot "assist" acceleration. There are even Volt drag race vidoes online from a drag strip - can't push the car harder than that - no engine usage.

Koz | September 8, 2013

I have a Volt and a Tesla 40. If you are getting 41-42 miles from your Volt on the highway, you are probably driving at 60-65mph and will see about 260-270 wH/m in a Tesla. Non-highway driving varies greatly because of the extra 1000lbs in the Tesla. With mild temps and reasonable stop/starts, 41-42 miles from Volt AER will translate into 290-330wH/m. There is no way around the higher burn rate with stop/start driving and an extra 1000lbs.

Another consideration for energy usage in the Model S vs the Volt is the vampire losses when off. The Model S burns about 2kwh/day while turned off. There are lots of threads on this and more precise numbers. Tesla is also working to reduce these losses but it will be at the expense of responsiveness in the remote app and in starting (booting up) the car.

Koz | September 8, 2013

Dr. Bob Reinke - That is not accurate for normal Volt operation unless the battery is depleted. There are discrete situations that brings the engine in the Volt on and high power draw is not one of them. Depleted battery, extreme cold, gas burn after extended period of no engine use, Mountain Mode battery charge level is reached, maintenance mode induced by open hood, and Hold Mode are the ONLY events that trigger the engine.

Koz | September 8, 2013

DouglasR - The Volt's generator maxes out at that rate but only uses it when the algorithms dictate. Mountain Mode has more scenarios that dictate this level, particular if MM is initiated with the battery deleted below the MM threshold. Under most scenarios the algorithms more closely match the generator's rate to the "perceived" power demand. It doesn't/can't match instantaneous demand but rather user recent averages and real time inputs.

Motobones | September 8, 2013

I can vouch for the fact that the Volt does not use the ICE at any point for acceleration unless the battery is depleted. The ICE does come on for me when the outside temp is 25 degrees F or less to help warm up the car, but it does not come on to aid acceleration. My experience is that the car accelerates better when the battery is fully charged and the car is in Sport mode, than when the battery is down and using the ICE.

bonaire | September 8, 2013

Yea, A full battery will have a higher voltage and any EV should have a bit more "punch" when full than when the battery is depleted and/or the electric motor has heated up.

carlk | September 8, 2013

@DouglasR I don't think the claim is true. Charging at 54kW means the gasoline engine is capable of providing power to run the car more than 200 miles per hour. Way beyond what is possible.

bonaire | September 8, 2013

Carlk, i think you are a bit mistaken here. A car accelerating from a stop uses far more than 54kw. That is only about 75hp. Where do you find your 200 mph idea from? It takes about 700hp or 550kw to make a car go 200mph (ie. Nascar type power)

Bighorn | September 8, 2013

You are misunderstanding his use of 200 MPH as a rate of speed rather than rate of charging the battery.

DouglasR | September 8, 2013

@carlk - How do you know 200 mph charging is way beyond what is possible? The Model S can provide up to 60 kW of regenerated power. Why couldn't the Volt provide 54 kW of generated power?

I don't know that it will sustain this high level of charging for very long. As I understand my brother's driving strategy, he uses mountain mode to increase his overall fuel efficiency on longer trips. He switches to mountain mode when the battery is partly depleted, which results in adding charge back to the battery before he arrives at his destination. He claims that the car charges up very quickly, and that his overall gas mileage is higher than when he uses normal mode.

Those of you who have a Volt can comment as to whether this makes sense. I'm only repeating what I've been told.

SUN 2 DRV | September 8, 2013


The Volt is NOT a pure series hybrid. In some scenarios the ICE does provide mechanical input to the drivetrain. The GM and Chevy engineers have been very clear in describing the scenarios when both the electric motor AND the ICE combine MECHANICALLY to move the car forward.

As a result, carlk is right that it's not always clear whether the Wh/m figure is strictly from electricity.

Motobones | September 8, 2013

To be clear about the Volt, it does not use the engine at all as long as there is charge in the battery (unless it is really cold and the ICE is needed to heat the car). Now after the battery is depleted and the ICE is generating electricity to power the electric motor that is powering the front wheels, there are situations where the ICE not only produces electricity but also helps power the front wheels through the use of a planetary gear set between the ICE and electric motor. But this only happens after the battery has been fully depleted. After the battery is depleted the Volt is not running purely on electricity generated by the ICE, but in certain situations is running on a combination of electricity from the ICE and power from the ICE.

bonaire | September 8, 2013

@Douglas, that mode seems ok but actually results in lower trip mpg than if he just left MM engaged from the start and ended the trip by switching off MM 15 miles from the end of the trip. I can get 43 mpg on a long trip in the Volt by not doing the MM recharging game. I tried the MM game on a trip of 1000 miles and got well under 40 mpg. Hve him try a trip not doing the thing you described.

bonaire | September 8, 2013

@joeh. yea, youmare right but only when the battery is depleted. The incorrect thing floating around here is that the engine is used for propulsion when the battery is full or above the MM engagement point and that is not true.

DouglasR | September 8, 2013

@bonaire - Are you saying you get the best mileage by being in MM and switching normal for the last 15 miles, or by staying in normal the whole time? Because I think he did say that using MM got him better mileage. Don't know if he tried leaving it in MM until the last 15 miles.

bonaire | September 8, 2013

If he runs it down to 3-4 miles and then uses MM to charge it back up, he can get more electric miles but overall lower mpg. I get over 40-41 mpg by starting the trip in MM and that engages the engine earlier but leaves the 15 mile buffer. At the end of the trip, just shut off MM and burn the last of the battery then plug in.

mrrjm | September 8, 2013

The only situation where the ICE is providing power to the wheels and electric motor in the Volt is at a steady 70mph with a depleted battery. Search the Volt on YouTube and view the powertrain deep dive 1,2,&3. I wish Tesla had something like this on YouTube. I've had my 2013 Volt for about a year now. Just ordered my Model S P85+. With the Volt I drive a combination highway/city 22 miles each way to work. I mostly always get 4+ miles per kw. And that's with the ac on and 55-70mph. If I drive really conservatively, time my stops for max regen, + ac off I can get 5 miles per KW. I will be really happy if I can get 4 mile per kw with the Tesla driving this way.


Bighorn | September 8, 2013

4 miles is doubtful, though I've only been driving mine a couple weeks.

AmpedRealtor | September 8, 2013

I think I did 4.3 miles per kW in my Model S today driving 60 miles roundtrip from my home in Buckeye to Phoenix to show a handful of properties to a client. I stuck to 65 on the freeway with a few bursts up to 75 to pass some trucks. I made sure I kept my energy usage under 40 kW generally except when merging onto the freeway. My average energy usage was 230 Wh. So am I doing the math right? 1 kW ÷ .230 kWh/mile = 4.3 miles. I drove conservatively in a similar way to how I drove my Prius.

Bighorn | September 8, 2013

Math looks good--very encouraging.

mrrjm | September 8, 2013

Nice on the 4.3 mls/kw. All my highway merges are long and downhill. So I hope I can do the same. If the model s has the efficiency of the volt and the acceleration of a super car plus the safety of a space capsule then I may have purchased the most perfect car. :)

shs | September 8, 2013

I just watched the Volt Powertrain video.

The Volt a very complicated system compared to the Tesla, with a traction (electric) motor, a generator motor and the ICE wth 3 clutches that allow multiple driving modes including 1 motor and 2 motor electric modes, and the combined mode where it seems like the ICE/generator motor is connected to the planetary gear thus directly driving the car.

The video is worth watching, if for no other reason than to appreciate the simplicity of the Tesla drivetrain.

logicalthinker | September 8, 2013

I can confirm the following: on the newer Volts, you can see the instantaneous kWh. On hard acceleration, my 2014 Volt puts out about 108 kW (i.e. 10C discharge rate, if you consider only the usable 10.5 of the actual 16.5 kWh battery) and on heavy regen, 54 kW (-5C) back into the battery.

The 2 killers about the Volt are 1) its extremely limited electric range... just barely enough for daily use; and 2) its 3.3 kw charging limit. SLOOW, compared with Tesla.

ELECTRICFAN | September 8, 2013

I just wanted to say that's the best explanation of W and Wh units of electric power I've seen outside a textbook. Great job. As electric cars become more and more common people are really going to need to understand these terms. In my opinion the Watt is the worst defined unit ever - not intuitive at all. It sounds like a measure of an amount or quantity, not a rate, and makes understanding electricity so much more difficult.

cfOH | September 8, 2013

As I posted over on the TeslaMotorsClub forum, I went out tonight and drove as economically as I could for ~20 miles around my local (hilly) highways and got just under 250 Wh/mile. That's in a P+.

So, it's possible. Not fun, but possible.

mrrjm | September 8, 2013

That's good. Real good.

fafner1 | September 9, 2013

A quick comment on the Volt. When the battery is above its normally allowed minimum a Volt will never start the ICE except to warm the cabin if desired in cold weather(or heat cycle the oil or burn stale gas if the car has been running on the battery for months). When the battery is at the minimum the car reverts to a "strong" hybrid. It runs the ICE but still uses the battery as a boast for more power or a sink if the motor is producing more power than the car needs (the motor runs at a series of near constant speeds, which I assume were chosen to minimize noise and vibration). Under low load conditions it will still turn the ICE off and run on the battery. I think Dr. Bob's brother in law's Volt was in hybrid mode. The car could back out of the driveway under pure battery, but started the engine once the driver stepped on it.

It is true the ICE on the Volt can directly transmit power to the wheels, but this is typically only done at high speed (above 70 mph). The ICE and the electric motor react against each other through a planetary gear set. My sense is that this was done as much to reduce the speed of the electric motor as to increase power.

If I got anything wrong, please excuse. The Volt is one little complicated car (although the complication is mostly in the software that blends all the different operating modes together).

mrrjm | September 10, 2013

fafner1- Having driven my Volt for a year I would say you hit the nail on the head. The only thing I would add in when the ICE is connected to the wheel IMO this only happens at around 70mph at a steady speed. It feels sort of like a torque is locked on an automatic trans. But it is very quick to release and go back into "generator mode".

As far as complexity yes it is. However far less complex then say 7 speed automatic. Or any automatic as far as that goes. I'm curious how long those 3 clutches with last. After living with the car for a year I think Chevy did an excellent job on this one. When my model S arrives I'll be curious to do some comparisons.


bonaire | September 10, 2013

The Volt is transitional. Once smaller, denser batteries are a dime a dozen, the almost all EVs will be simpler. For the next few years, until this happens, the Volt is a great for people with one car needs, who want to srive locally on electricity and at distance on gas. If everyone drove a Volt, gasoline usage would drop a very substantial amount.

To get the charging infrastructure to the point of supporting the national car fleet, it will take time. It may be said that we cannot go all electric until oil runs out. It is a race against time that most consumers really dont even care about, let alone can afford to do. Since plug ins are well short of 1% of all new cars sold, it will take multiple decades to make a substantial change. Tesla isnt THE answer, as many Teala fans try to say. It is one part of a much larger program by almost all vehicle manufacturers to get ready to transition, in a few more years, the number of plug ins will increase along with their costs decreasing to a point that most people can afford. What makes things happen for a world car will be a 100-120 mile BEV for about $20-22K before incentives.

mrrjm | September 14, 2013

Yeah and that's a problem for my business model. I run a automotive repair shop & bev's are bad for business. They don't need much repair if any at all. My volt all I've had to do in the last year is rotate the tires twice.