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is my 12V battery effecting my MPG?

Discussion in 'Gen 2 Prius Fuel Economy' started by Peteab, Mar 22, 2011.

  1. Peteab

    Peteab New Member

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    Hi I've had my 2005 Prius for around a week now and I'm averaging 52mpg (UK gallon).

    I followed instructions on this forum for checking the 12V battery and found that it was a volt or so under the recommended. would this have much effect on my mpg? as far as i can tell the battery has never been changed since new.

    any advice is much appreciated!
     
    #1 Peteab, Mar 22, 2011
  2. Britprius

    Britprius Senior Member

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    52mpg is not bad for a new owner but a poor 12v battery will affect mpg, do not buy a new battery from the dealers as the correct fit batteries are readily available from motor shops at much better prices about £45- £50.
     
    #2 Britprius, Mar 22, 2011
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    As long as you haven't recently attempted charging, the battery voltage for a healthy battery should be around 12.6 volt or higher. If you have charged it, just drive it for a bit, with the headlights on too, before checking voltage. A volt or two low (assume you're checking with a digital volt meter) is significant:

    4 or 5 years is a good run for a battery. If you're on the orig. battery you've been lucky. It will leave you stranded soon: get it changed.
     
    #3 Mendel Leisk, Mar 22, 2011
  4. Hal W

    Hal W New Member

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    Are you talking Imperial gal.? The battery should read about 12.6 after sitting over night. Hal
     
    #4 Hal W, Mar 22, 2011
  5. seilerts

    seilerts Battery Curmudgeon

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    You folks in the UK are lucky, I hear that you can get the Optima D51 battery with Japanese terminals there.
     
    #5 seilerts, Mar 22, 2011
  6. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    There are many ways a 12 volt battery may fail. One of those ways really pulls down the fuel mileage. (single dead cell) Other ways to have an old battery fail may not effect MPG.
     
    #6 JimboPalmer, Mar 22, 2011
  7. uart

    uart Senior Member

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    What exactly were the voltage readings you got?
     
    #7 uart, Mar 23, 2011
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