GM Shrinks Volt's Gas Tank


General Motors has downsized plans to equip the Chevy Volt plug-in electric car with a 12-gallon fuel tank. The original idea was to give the vehicle an extra 600-mile driving range once the lithium-ion battery pack ran out of its initial charge.

The tank has been shrunk to hold fewer than 12 gallons. GM won't say exactly how many gallons it will now hold, other than a source saying, "We're working on that."

GM's goal is to begin selling the Volt by the end of 2010.

The original target with the Volt concept was for it to run in battery mode only, without burning a drop of gas, for up to 40 miles — about the distance most folks travel each day — before the lithium-ion battery pack needed to be recharged. 

That goal hasn’t changed. Initially, though, it was intended to be able to travel up to 600 miles more after that using a small on-board gas engine/generator to create more electricity to power the car. It would then need a one- to two-hour recharge, or the gas tank would need to be refilled.

The target now is to travel 360 miles after the initial charge wears off rather than 600.

GM says because most cars travel 40 miles or less each day, there was really no need to have a 12-gallon fuel tank — and the added weight — to extend the range by 600 miles.

"Most cars today have a range of more than 300 miles and less than 400 miles before refueling,” said Jim Hossack, vice president of AutoPacific, an automotive research and consulting firm. “GM didn't need a longer range because most bladders can't go 600 miles.

"By going with a smaller tank it means GM can take weight and price out and make Volt a little lighter and a little cheaper, and that's what you call making an improvement.”


Like a smaller gas tank is going to make a huge difference in the price.

I believe his wording was "little" meaning not huge ;)

Amuro Ray

Sooner or later - sthg ELSE will change. Maybe the distance on the battery, maybe sthg else, but definitely sthg else. Why? Because the vehicle is still in concept phase. When reality hits, many of the concept ideas won't hold :(

However, I don't know how much $ this will decrease with the shrinkage in the gas tank, but very unlikely to be $20K. Why $20K? Because for less than $20K (Volt's 'bou $40K, right?), you can get vehicles like Versa, Corolla, Sentra, Fit, etc. that seats 5 people and also go OVER 400 mi/tank of gas. My calculation shows that Volt will go 400 mi too (360mi on gas + 40mi on electricity). If you spend 'bou $25K, you can get the Hybrids from Nissan, Toyota, and Honda (I don't know 'bou Ford Escape Hybrid mileage) that goes much beyond 400 mi.

Well, this concept's practicality seems to be getting worse since its debut! :(


I think the space it saves by reducing the size of the tank is most important...


Doesn't get gas get old in a tank if its unused for a long time? How would you manage a 12 gallon tank if you don't drive over 40 miles very often?

So Dave it will be about a $100 cheaper because of a smaller gas tank? Wow a $100 off the $40k price tag. Where do I sign up?

Sounds like they failed to get 50mpg in gas mode. Did GM have any comment on that?


It is true that concepts change over time before they go to production but those changes are mainly due to unrealistic options like 22 inch wheels. The Volt is a totally new concept that may take several iterations to perfect before production. But, it's unrealistic to compare it to other concept vehicles - apples to oranges.

Additionally, you won't spend any money on fuel if you don't go over 40 miles per day and if you do, chances are that it won't be too many miles more than that. So, go ahead and spend your 20k on a Versa, Corolla, or whatever else you want but again, that's an apple to oranges comparison.

Point is that this is a great concept and many people are in denial of that fact. You can't really argue with the fact that the Volt is an answer to our oil dependence.

Depends what the tank is made of but the price of plastic wouldn't be that high no. Again, little. But hey, automakers change the layout of switches and knobs all the time to shave pennies off the car's cost. So a smaller gas tank for a lighter car (meaning better mpg) is worth it even if just a few pennies are shaved off. Again, folks are arguing with us over a quote from someone else ;)

Amuro Ray


It's not comparing apple to orange. A car is a car is a car. Diff b/n Volt and the rests "regular gasoline" cars IS how power is generated; Volt still has a gasoline engine, 4 wheels, etc. Nothing more.

Technology is expensive; so to attract buyers, the technology has to be ground breaking. To me, the Volt now seems to perform more and more like a regular car (or hybrid) in terms of mileage and how it generates power (like a hybrid). What incentives will it have now over regular hybrid or econo car? For $20K MORE and get similar mileage as a regular car, and $15K more (with less mileage) than a hybrid, the incentives are getting fewer! Look at Tesla! @100K they have no trouble selling it 'coz it's innovative and ground breaking.

The original Volt concept was ground breaking and innovative; the current one is not!

Nothing like being up on the news - this
change occurred over four months ago, and the
main reason was that GM is concerned that the gas in the tank will go sour before it's ever used - an entirely valid concern, seeing as how over 75% of commuters don't need 40 mile a day and non-commuters much less. The tank was originally a two piece affair, one on each side of the car's spine. Now it's one piece. The car gets 50MPG of fuel, so a 360 mile gas range translates to a little over 7 gallons,
a calculation that's hardly the impossible feat that this article imples. Jeez!


All this discussion because they are reducing the gas tank from 12 gallons to like 7 gallons!!! Does that really change whether it is groundbreaking and innovative?


Keep in mind that the car can go 40 miles without using any gasoline. Last time I checked you can't do that in any one of the cars you've listed. The Volt premium will pay for itself in a short timespan if the daily driver doesn't commute more than 40 miles/day. NO GAS would be used and therefore, no fuel cost whatsoever (in theory). Notwithstanding, the cars you mention may be a better fit insomuch as they cater to the lifestyle of a specific customer. So for example, one may choose a Versa over a Volt because they need the extra legroom, and so on..


don't know much about the Volt -- how long is charge time? how fast is it estimated to be? is it 40 miles whether driving is enthusiastic or frugal?

The original Volt concept was ground breaking and innovative.Very interesting to read.


My guess is that Chevy also realizes that the current lithium batteries that they are working on have been dramatically improving in the amount of chrage that they can hold. Therefore, the Volt is much liklier to be able to go much farther than only 40 miles on an electric charge overnight. Plus, they can see that Toyota is way ahead of them in using solar panels on the Prius roof (and possibly hood)for additional "on-the-go" recharging by solar power. A 7 gallon gas tank may be more than enough fossil fuel to carry to supplantment the electric and solar energy power plant in the Volt.
I am really excited about what we are witnessing in the auto industry thanks to the Japanese technical innovations and the Middle Eastern nations practice of extortion. Unfortunately, we needed them both to get off of our lazy keysters and do something for ourselves and to regain some of our pride. Even Boone Pickens has had a belly-full of it.

My Camry Hybrid goes 500-650 miles on a tank depending on conditions and I do that regularly. Clearly GM isn't targeting me with the Volt.


My take on the gas tank size is longterm P.R. People always fuss about how much it costs to fill up a tank. They don't fuss about their MPG, or how long their tank lasts. GM is smart to make the tank small - they don't want people saying that it costs as much to fill up a Volt as it costs to fill up a .....


I had a camry hybrid for a while and my bladder couldn't handle 500-600 miles. I had to stop anyway, may as well fuel up.


AR Wrote "NO GAS would be used and therefore, no fuel cost whatsoever (in theory)."

Yes, the Volt is being designed to get 40 miles on electric only. Did you think how about how those batteries are going to be charged?

By the engine in the car. That means that the car will still use gas.

Drive 10 miles, park and the engine will recharge the batteries. Drive 100 and "at the 40 mile mark", the car will start the engine AND charge the batteries. Say hello to driving a slug.


OK, for those people who are saying "My Camry Hybrid goes 500-650 miles on a tank depending on conditions and I do that regularly"

Lets say you drive 40 miles every day, you get 600 miles per tank. Every 15 days you have to fill up. Gas is $4/gallon you have say a 10 gallon tank, you pay $40 every 15 days or $2.66/day.

Now, lets say you drive a volt that same distance. 40 miles each day, recharging each night. Each recharge costs you $.85/day (source

So your hybrid is $2.66/day the Volt is $.85/day meaning your hybrid is just about 3X as expensive to drive.

Lets take the difference ($2.66-$.85=$1.81) x 365 days= $660.65/yr difference. $20K price difference divided by the $660=30 years before the total costs even out (excluding electricty costs). However in the mean time you are releasing much less carbon in the air, etc.

If you have a hybrid does it make sense to go buy a Volt? No, not at all. Even if you have a gas car that gets great mileage its not really worth it. It is simply another option out there though.

Personally we plan on replacing one of our cars around 2010 depending on how things turn out. I drive <40 miles a day and am willing to spend $35-40K on a new car, so why not get it?


40 grand (if the price doesn't continue to rise) is alot of money for a car that competes with the Prius at 25k.

And 15 grand pays for a lot of gas. Sorry, no sale.

Wouldn't trust a first year GM car anyways, look at how bad their mild hybrids are (leaking batteries, pitiful gas mileage).
40 grand is a lot of money to be a guinnea pig.

The Prius is on its 12th year already, there are hundreds of thousands of them on the road. I'd much rather buy something that is proven and has a solid reputation, especially when I can buy it for 30% cheaper.

"Drive 10 miles, park and the engine will recharge the batteries."

That's not true. The engine only supplies energy to the batteries when they are nearly discharged and the car is running. It doesn't completely recharge them either because it's cheaper to plug it in. I don't think there are any hybrids that recharge their batteries when the car is off.

GM really needs to stop hyping this car if people are going to get upset over every insignificant change. Just shut up and build it.

Fred G

Smaller gas tank will: reduce the weight, reduce the cost, reduce the potential problem of 'stale' gas, reduce psychological impact when filling the tank. This is a wise move.

bogus numbers

Lots of bogus numbers being used here.
20K price difference? It is less than that.
$4/gallon gas? It is $4.70 where I live NOW and it will go up in price in the future.
Stop with the bogus numbers people.

Murdock buster

Murdock is filled with wrong numbers!
600 miles per tank . . . 10 gallon tank?!?!
Your car Camry Hybrid gets 60 miles per gallon?!?! NOT! (much lower)
$20 difference in price??? NOT! (try lower)
$4/gallon gas?? NOT!!! (try higher)
Why all the lies Murdock?


This another example of GM doing the bare minimim rather than producing the best vehicle possible. Who cares what the average bladder holds? And what genius spent his/her time recording that data?

Really, how much weight was reduced? How much space was gained? What is the difference in the price point for the car? Why not have one for people who do not want to see a gas station for 600 miles and another for those who only tool around close to home?

I had an interest because of the concept and the nice design, but if GM are going to continue cutting corners etc., my money will stay with a certain barvarian manufacturer that likes to make cars without considering bladder capacity.

The Camry Hybrid has a 17.2 gallon fuel tank and is rated at 34mpg highway so 600 miles on a full tank is achievable. You can buy a new one for about $23k so $20,000 from a possible Volt price is probably right. $4 a gallon is close to the national average. Of course it will vary depending on where you live. I pay $3.80. Murdock - you're right on track.

This 40 mile no gas thing is interesting, but I wonder if there is a flaw in that thinking.

I drive 40 miles one way to work. So will the car run the engine to recharge the battery while its parked at work? If so, doesn't that mean its getting precisely zero MPG while it is sitting there?

Wouldn't it be better to go say 20 miles without gas and then for the last 20 miles a mix them so that the batteries recharge? I understand that during the 40 (or 20, in my scenario) you are getting theoretically infinite MPG (well, not really, something had to generate that electricity, but I digress.) But it seems to me it would be better for the driver to have some control over it. In the sense that I can tell the car what my plans are over the course of the day so it can plan how to recharge accordingly.


>>Murdock is filled with wrong numbers!
600 miles per tank . . . 10 gallon tank?!?!
Your car Camry Hybrid gets 60 miles per gallon?!?! NOT! (much lower)
$20 difference in price??? NOT! (try lower)
$4/gallon gas?? NOT!!! (try higher)
Why all the lies Murdock?<<<

I'm sure you've heard the word example correct? This was one of them. Where I live gas is hovering around $4/gallon right now, maybe up to $4.10 if you try really hard to find some that expensive here.

If the car can drive 360 miles on a 7 gallon tank (for example) and the Camry can drive 600 miles on its 17.2 gallon tank then you can use those real world figures to get accurate numbers rather than examples.

BTW Murdock never said any of this, it was Stromm you're all quoting.

Also, the weight savings in a smaller tank is also in the weight of the gasoline at about 6 Lbs./gallon that equals about 30 pounds of gas you're not toting along when you're not using it.

Don Robertson

Nice try GM but my 1977 Honda CIVC 5 speed got 35 town and 45 highway. The cost for the car $3,600. Gas just hit $1.00 a gallon for the first time. Now any car out there get's 30 miles per gallon and costs $30,000. What's missing in this picture. Thanks but no thanks


Adrock, I think you are misunderstanding the concept slightly.

You are correct that the car will run up to 40 miles on battery only. So you get to work, the battery is dead. The car WILL NOT sit there idling while you are off working. You will just switch the car off.

However, when you return to drive home, if there is no charge left the small engine will fire up and charge the battery as you are driving. Obviously, when the engine is running you will probably only be getting about 45-50mpg as you are burning fuels. However, because the engine isn't actually DRIVING the car but simply charging the battery, the engine can run constantly at it's most efficient speed.

Then, when you get home at night, you'll plug the car into the grid to charge it fully for the next day.

The benefits of this kind of technology are multiple, but the key is that, even if you end up driving home with the gas engine running the whole way, you are still going to be getting a combined average (morning/evening commute) of DOUBLE the 45mpg because you got to work using no gas at all. I dunno what GM is estimating, but that looks to me like 80-90 mpg easy.

Does that make sense? It isn't a traditional hybrid like a Prius, but seems like a much better idea.


Sorry for the double post...

As an example of how the car will work when being charged by the petrol engine - think of it like a laptop computer. A laptop can be COMPLETELY dead, but as soon as you plug it in you can use it while it charges up. The Volt will be the same - it'll charge more quickly than you deplete the battery as you drive home though I'd imagine you'd have to go on an EPIC drive to charge it completely.

So, why don't they put in the large tank and let people fill it up to whatever amount that they want? Offering the larger tank as an option would be a second-best choice. It must be a matter of national security LOL.

Hey will it really help ? It was really very interesting to read the article !! Thanks !!!

Dan Petit

While weight savings for the gas and tank help, between now and final production, other types of weight savings (not affecting obvious specs) may take place. The sooner the obvious ones are made public, the better related industry-suppliers can adjust their businesses if needed.
One big problem I see a lot is where an owner of a vehicle which has only several gallons of gas in their tank puts a whole 20-ounces-for-20 gallons-of-fuel tank additive into the tank in a really destructive overdose, (which ought to be unnecessary if one is using a "top tier" gasoline in the first place).
Suppliers of various fuel vapor emissions devices, for example, need to know the volume of the gas tank as soon as finalized, so that the lead time for contract-bidding is adequate to prevent "last-minute" cost overruns and design problems. The sooner all specs are finalized, the better the chances of more competitive bidding, which ought to help keep production costs down.
Dan Petit Austin, TX.

Troy S.

Fred G.

It will also reduce the range of the car. Not a smart move in my book of long distance driving.


Again I think it's important to see the transition between what we as a country have seen in just the last few years. You see nothing but Hybrid advertisements these days and it's only been half a decade or slightly more since we made some worthy effort to curve our energy dependence. Everyone who's anyone with common sense knows that total energy dependence won't happen over night but it's happening faster than i thought it would. There is always more we could do but i think Volt has the right idea...and like most of you said it's still in concept phase.
40 miles without using fuel...this is it's selling feature. MOST people, not all travel that each day. So not spending any or no gas at all is huge savings. If you think a new technology won't cost a lot, your sadly mistaken. Though electric cars are not a new concept it's still new to reintroduce it after all this time. Consumers have to be led into technology not have it dropped on top of them...that's just the way the economy works. Chevy makes a good stand here, i think the cost of the vehicle will pay for itself if you don't buy any gas for it. The prius isn't exactly a cheap vehicle either.


Thanks for clarifying the technology Mart, sounds like a smart concept. Does this vehicle also feature regenerative breaking as well? I know some vehicles have a feature which transfers energy used by the breaks to help recharge the battery. If what you say is fact than the combination on minimal gas usage (charging the battery) and electrical use of the engine sounds pretty efficient in my mind. 80mpg? That's pretty amazing. Was there or was there not a guideline for automakers to have a vehicle to achieve 100mpg by 2010? or 2012?

thanks for providing such a detailed elaboration of the technology


I would say that the smaller gas tank is driven by several reasons: not needed under current daily miles target; saves a bit of weight on the tank and the fuel (about 8 lbs/gallon); get to use a higher percentage of the volumen when the motor is ON for recharge; MORE PROFITS FOR GM.

Sometimes I wonder whether its even worth it to but an electric car. For now it seems it would just be better to just buy a remanufactured engines and build an energy efficient car yourself!


I am sure they reason they shrunk the tank was marketing. People are always telling me how much it costs to fill up their tank, and use that as the basis for how much gas their car uses. I tell them that it is irrelevant, and what counts is how much gas the car actually uses. Then they go back to how much it costs to fill their tank, vs. another vehicle they or someone else owns. With a 6 gallon tank, a Volt would be a super economy car, but with a 20 gallon tank, a gas hog in their opinion.

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