Settle down: Volt batteries can recharge while driving
Click above for high-res gallery of 2011 Chevy Volt
Inside Line kicked up a dust storm yesterday by claiming that the 2011 Chevy Volt could not recharge its batteries while driving using its on-board, range-extending 1.4L gas engine. 40 miles of electric-only drive was it, and then the battery packs become "400 pounds of uselessness" was what IL said. They got this impression from a press release issued when the production Volt was unveiled to the public, which stated that the gas engine could only "sustain" the battery pack's charge and not increase it. GM got its communications crossed and apparently confirmed IL's take, but has thought about it some more and today reconfirmed what we initially thought was true, that the Volt's gas engine can recharge its batteries while underway.
What the Volt's gas engine can't do is completely recharge the battery pack to its full capacity. Rather, when load conditions are light the gas engine will send surplus electrons to the battery pack, which will also be receiving extra charge from regenerative braking, as well. That sounds about right to us, as we've always been told that constantly charging a battery to its maximum will shorten its life, as the optimum charge range is usually between 20 and 80 percent, not completely drained and not completely charged. GM is determining right now just how much it wants to let the gas engine charge the Volt's battery pack, but rest comfortably knowing that your future Volt won't be carrying around 400 lbs. of uselessness when the charge runs out.
Gallery: 2011 Chevy Volt
[Source: Inside Line]
Reader Comments (Page 1 of 3)
MoonRover 1:35PM (9/26/2008)
Government mpg rating...........100mpg, now what do you think about that.
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Torrent 1:35PM (9/26/2008)
omfg.
DKB_SATX 2:53PM (9/26/2008)
Well, that's about what it returns when running the current EPA test, starting from the maximum state of charge (as you would when you leave your house in the morning after having been plugged in overnight.)
The feds want to hobble it, there's been talk of forcing them to run the test only with the battery starting at its minimum state-of-charge, which would return about 50 mpg. The other rumor I heard is that the feds want to require the generator to bring the battery up to the max state of charge by the end of the test... I'm not sure what mpg that might return, but it would be amazingly stupid even for the feds, since that's not a duty cycle that would exist in the real world.
tbss_in_the_D 1:40PM (9/26/2008)
I am very interested in how far this thing will be able to go on the expressway on a full charge and with a full tank of gas in normal conditions.
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montoym 6:41PM (9/26/2008)
Judging by GM's previous information, about 400 miles. Similar to what you'd get out of most other vehicles on the road.
Granted, that's with an 8gal fuel tank as well. The original design did have a larger fuel tank giving a range closer to 600 miles. But, considering that the average user likely wouldn't be using a great deal of gas anyhow, the decision was made to decrease the tank size for more space.
So that does even out to around 50mpg, but the first 40 of that is done using no gas at all.
Again, it's really not a vehicle designed to be a freeway flyer. Yes, it will still attain good mileage while doing so, but, it's main claim to fame is the ability to travel that first 40miles using no fuel at all making it an ideal commuter vehicle.
Tim 1:43PM (9/26/2008)
GM can say whatever they want since no one outside the company has been allowed to drive the Volt. The leaves the media to only speculate about the Volt's capabilities. When they let the press drive one I'll be a believer until then VAPORWARE.
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tankd0g 1:59PM (9/26/2008)
I have no doubt this story has some legs, the test mules probably can't charge the battery while driving. This is the biggest hurdle of the design, to somehow move this car with a 1.4L engine and charge the battery at the same time. A feat I still think is impossible unless the cars performance is extremely restricted.
tbss_in_the_D 1:57PM (9/26/2008)
Wow you are really still believing that this is not going to happen? It is not like GM is telling us they have developed some unknown fuel source. I really do not get why this is so hard to believe.
DKB_SATX 2:33PM (9/26/2008)
tankd0g: your comment is off base. A reasonably aerodynamic car doesn't require much power to cruise at 70 mph, it's accelerating from a stop, climbing hills, etc. that require a higher percentage of the power from our vastly-overpowered modern cars. While cruising down a level road, even a 1.4L running at its peak efficiency point (the point where the torque and hp curves cross) will have excess power that can be devoted to charging the battery.
Now, if you accelerate from highway speed to pass someone, the car will most likely dip into the battery in addition to the full power output of the generator. That's the best advantage of hybrid drive, you have power in reserve that is more efficient than having to size the internal-combustion engine for the maximum required power for all normal operating regimes.
MoonRover 2:40PM (9/26/2008)
The volt never runs off the engine, the engine is for charging the battery pack. The power to the wheels comes from the battery that is being charged by the engine, always, that is what makes it an electric car.
Brownsound 3:57PM (9/26/2008)
@DKB
According to what you said, wouldn't an engine's peak efficiency point be different depending on what units of power and torque you are looking at? I drive an AP1 S2000, and I don't even think on an evenly scaled WHP/Ft.Lbs. dyno the curves cross at all! If they do, it is very low in the RPMs, not anywhere near the presumed peak efficiency point.
Ford Wannup 3:41PM (9/26/2008)
It's not exactly vaporware, but GM introducing this thing and breathlessly proclaiming superlatives, during the course of a very public development process, certainly doesn't help manage expectation properly.
Here's a pretty good article about the challenges that remain:
http://www.technologyreview.com/Energy/21387/
pragmatic 1:46PM (9/26/2008)
Well, most cars in America normally haul 200lbs of uselessness behind the steering wheel, so what's another 200 on to that?s
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Berto 2:11PM (9/26/2008)
Oh no!! We Americans are fat and dumb!!! What next? We like hamburgers?
Idiot.
arumage 2:15PM (9/26/2008)
That comment proves that there is about 3 lbs. of uselessness sitting between your ears.
Sandok 3:08PM (9/26/2008)
... It's not as if he's too wrong. Americans are the fattest in the world...
Drewboy 3:44PM (9/26/2008)
No Sandok, the Aussies have taken that prestigious position from us now.
LMBVette 1:46PM (9/26/2008)
Ah...thanks for clarifying AB. When I read that it didn't make sense to me that it wouldn't recharge the battery at all.
@Tim...Vaporware? Seriously dude....?
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EVan 1:46PM (9/26/2008)
This was already common knowledge to people familiar with the E-FLEX technology. Once again a case of a journalist unable to understand technical subjects.
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Doug 2:52PM (9/26/2008)
"Once again a case of a journalist unable to understand technical subjects."
Exactly!