A Channuka Fable, or, the Little Battery that COULDN'T

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rufaro, Dec 21, 2008.

  1. rufaro

    rufaro WeePoo, Gen II

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    Once upon a time in sunny Southern California (The Land of Fruits and Nuts), there was a 2006 Prius sitting under a car cover in a driveway for 8.5 months. The car had everything, including its SmartKey button, shut off. It was being started every couple of weeks. Twice during that time (once in the summer, and once in December) the car needed to be jumped (once before the SmartKey feature was turned off and once after). Oops...the 2nd death occurred a couple of weeks ago and the corresponding jump has not yet happened.

    There seems to be no correlation to the weather--it was neither that hot during the summer, nor that cold in December--despite what other Angelenos might tell you--THIS transplant KNOWS hot and cold!).

    Should WeePriQueen (shouldn't every fable have some royalty in it?) be worried about the long-term health of her chariot's batteries?
     
    #1 rufaro, Dec 21, 2008
  2. efusco

    efusco Moderator Emeritus
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    Why would you keep the poor beast cooped up that way and not let it run and be free to roam and do what it was born to do?

    It certainly is not good for the batteries to let it go unused so much...esp. the 12v, but I have to believe it can't be good for the traction battery either as it's never getting a chance for the ECU to cycle it for maintenance as it's designed to do.
     
    #2 efusco, Dec 21, 2008
  3. jdenenberg

    jdenenberg EE Professor

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    Listen to the good doctor. The 12v battery takes a while to charge back up using the "constant voltage" charging method in your Prius so just running it a short time isn't enough.

    JeffD
     
    #3 jdenenberg, Dec 21, 2008
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    To amplify upon Jeff's point that the 12V battery takes some time to recharge:

    My Highlander Hybrid is lightly driven so the 12V auxiliary battery is not kept in a state of full charge. Today we drove it 465 miles from OC to S. Lake Tahoe, leaving at 6 AM.

    Before starting the trip, the battery voltage was 12.2V, hence it was probably at ~50% charge. Midway during the trip we stopped for lunch in Bishop, along US 395. After having lunch I checked the voltage and it was 12.4V.

    After arrival in Lake Tahoe at 3:30 PM I checked the voltage after the car had been IG-OFF for 30 minutes and the voltage was 12.5V. (Fully-charged is considered to be 12.6V-12.8V.)

    Therefore, it took 9.5 hours of charging for the battery voltage to increase from 12.2 to 12.5. Since the Prius inverter setup is similar to HiHy, both producing ~13.8V on the DC bus, similar results can be expected.

    Note that the HiHy battery is of traditional wet cell design (unlike Prius) since it is located in the engine compartment and safe venting is not an issue. The battery has a viewing window for one cell.
     
    #4 Patrick Wong, Dec 22, 2008
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