Battery Boosters

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Bob_Stan, Apr 20, 2009.

  1. Bob_Stan

    Bob_Stan New Member

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    Will those battery boosters that plug into a power receptacle (i.e. cigarette lighter for us old folks) work to start a Prius with a run down 12v battery?
     
  2. firepa63

    firepa63 Former Prius Owner

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    No. If the 12v battery is dead, the 12v outlets will be disconnected. They come alive in the IG-ON mode or the READY mode (can't remember which). So with the outlets out of the circuit, there's no way to backfeed the 12v system.
     
  3. Rokeby

    Rokeby Member

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  4. jdenenberg

    jdenenberg EE Professor

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    Bob,
    You have choices other than the "easy" rewiring of one of the auxiliary power plugs to stay on (there are two). You can also jump the 12v battery from either the designated terminal in the engine compartment (see your owners guide) or by a direct connection to the battery in the "boot" (British speak). Just be very careful to get the polarity correct as reversing the booster leads can result in an expensive repair.

    You Prius can pull a significant current when first attached to the boosting source to start charging the little 12v battery so wait a while before pressing the power button to let this surge die down (then the in-car battery can help as it will be partially charged).

    When you press the power button there can be another short, high current (~30A), load to run the brake boost pump so the boosting battery needs to be able to supply that as well (so much for some discussions about using flashlight batteries to start a Prius).

    When I travel I have a small booster in the trunk, but the several times I have used it was to help others with their dead batteries. My 2004 Prius with 145,500 miles still has the original battery, but it has never been accidentally drained.

    JeffD

    ps: you can perform a simple health test of your 12v battery. A description of the procedure is available at: Checking 12v Battery Health - Hybrid Car Forums
     
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