Should Range-Extended Cars Have a "Battery Saver" Mode?

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At the 2011 Geneva Motor Show back in March we learned an interesting bit of information about the 2011 Chevrolet Volt's European cousin, the Opel Ampera.

Unlike the Volt, the Ampera is to be equipped with a "battery saving" mode, whereby the driver can hold back the electric mode for when they require it, rather than starting their journey and using up the 40-50 miles of electric range from the get-go. It's also been announced that the European version of the Volt will feature this option.

So should the American Volt - and other range extended vehicles due in the future - be fitted with a battery saver mode?

The reasoning behind the Ampera's mode is to prepare for future European policy that may require some city centers to be fossil fuel-free, and others such as London where electric cars aren't required to pay almost $13 a day in "congestion charge" fees.

If you'd already used up your EV range by the time you got to the center, on a business trip for example, you'd be unable to enter the city. Holding an electric mode for later means when you reached the city limit, you could press the button and glide in entirely fossil fuel-free. No restrictions, no fees.

It's not just a way to get around local restrictions, either.

For the environmentally-conscious, saving the EV mode for crowded cities means reducing local pollution, both in terms of emissions and noise.

You're also likely to get better use from the electric range in a city too - 40 or 50 miles could easily be several days driving around a city, whereas it might be less than one trip on the freeway.

So why is the U.S. market Volt not equipped with the feature? Rob Peterson from General Motors told Automotive News (subscription required) that "There are no plans to add this feature in the U.S., as regulations require the vehicle to operate in its most fuel-efficient/ lowest emission mode first."

Even so, the EPA test doesn't necessarily require the car to be run under its greenest mode first, so on face value it seems like an oversight. However, it's understandable that GM doesn't want to potentially hurt the car's EPA rating, as ultimately that's what sells the car.

The U.S. doesn't currently have the sort of restrictions found in many European cities so currently there is no specific need to hold the electric mode for a later time, and many drivers will still make most of their journeys on electric power alone.

So should range-extended cars have a battery save mode? Not necessarily, but that doesn't mean we shouldn't have the option.


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Comments (12)
  1. It's really a simple thing to let Volt owners have this option, so why not? I'm sure if you knew you were going to do a bit of highway driving that you may want to use your electric mode after you arrive in the area of your destination.

  2. It always seems easy to add, yet one more, button. I really think the Volt should be kept as simple to operate as possible and that means no button.

    One question, how will the people in London know if I am operating my Ampera on gasoline or electricity?

  3. Dashboard display shows that. Ever been in a Prius? Same type of display, shows when gas engine is running.

  4. Ele I think what John meant is how are the authorities going to know, after all they are the ones dictating the requirement in the first place. I do not see a logical way of enforcing this and relying on the driver is a non starter.

  5. Now, really. How likely is it that any city will be able to only
    allow non-fuel vehicles in the lifespan of any car now on the road?
    Worrying about that eventuality sounds awfully pointless.

  6. @Ramon: Won't happen here, but it is under serious discussion in more than a dozen European big cities. London's congestion charge already exempts zero-emission vehicles, and continental European cities are considering much more aggressive measures than that.

  7. I think the idea of "local pollution" is a concept that needs to be pressed more. In areas with a lot of vehicles (like cities) having millions of vehicle idling creates measurable amounts of local pollution that measurably increases health problems and premature deaths.

    If you want a acute example, stand near a diesel bus when it is accelerating. Then for comparison, stand near a CNG bus. You will immediately get the idea.

    Actually, the problem in cities is always like this, but you can't detect it as easily and it is hurting you.

  8. They should have the button , not to save the battery,but to save the engine. Engines need to run from time to timeor they could lock up. Also, fuel gets stale. I've seen You Tube video of Volt owner refueling after 4200 miles for the first time. 5-6 months and 4-5000 miles and you're gonna want some new fuel and run engine a few minutes every other week.

  9. Part of the Volt's control electronics monitors the time since the engine has run, and if it hasn't run in many weeks, asks the owner for permission to switch it on briefly to circulate the fluids and generally keep things in running condition.

  10. There's already a mountain mode - this should be extended to allow a setting to configure this mode to a specific battery charge level. Seems like a fairly simple software upgrade to me - allow us Volt owners to determine our personal optimal battery hold back. Personally, I'd like to be able to store/recharge to near full during the 70-80 mph on the freeways and then determine when to go back into 'normal' mode and become gas free again. This should improve overall gas mileage by giving more choice of 'highest and best use' of EV miles. From my 24,000 Volt miles, it would be any time driving under about 55-60 mph.

  11. Actually, as stated in another posting here, The Volt builds/has an electrical reserve which it will run on, no Gas, for a mile or more at city speeds of about 25mph or so. My Volt has done that. Additionally, I have had a "surplus" of extra charge after using mountain mode up a grade that allowed me to travel almost ten miles further on electric power.

  12. It does not make sense to force the battery to discharge before the range extender starts up. The most efficient use of the engine is during highway miles, so why should I have to drive highway miles on battery? If I need to do a trip of 100 miles to another city, then drive around that city for 30 miles, I would rather have the freedom to select gas operation once I hit the highway, where my MPG will be highest, rather than ending up driving for 30 miles around town on gas getting less MPG. Overall I would use less fuel, right? But we are not smart enough here in the states, I guess.

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