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2010 12v battery heavy drain of 1.1Amps when parked

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by swishfish, Apr 10, 2012.

  1. swishfish

    swishfish New Member

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    My first posting. Forgive me if this was already discussed.
    I just bought a 2010 prius (26k miles..prior collision.. so no warranty) for my wife. The battery drains in just 3 days if left unused. I had Toyota install a new battery. Again 3 days left parked and battery was dead.
    I locked myself in and measured the consumption. It drains at the rate of 1.1Amps when parked. That looks very high consumption.
    I want to measure with SKS turned off, but thats going to be tricky. I believe SKS resets when battery is reconnected.

    Has anybody measured the drain rate when parked?

    I measured like this:
    (+) terminal connected. (-) negative terminal connected via multimeter
     
    #1 swishfish, Apr 10, 2012
  2. RichardAK

    RichardAK Member

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    I had read on another site that the discharge rate was only about 12ma. I'm surprised that your battery even lasts for 3 days discharging at 1.1amps! More like one day as I think it is only 25-30ah capacity.

    I guess I would look for small lights left on such as glove compartment or other draws such as an aftermarket amp. In the old days, I just kept pulling fuses until I found the circuit drawing power. Maybe others have more ideas.
     
    #2 RichardAK, Apr 10, 2012
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  3. JimN

    JimN Let the games begin!

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    :welcome:
    Do you have any aftermarket items installed? Did the previous owner mod a 12v outlet to be hot & have something always plugged in? If it isn't something obvious since I'm not an electrician I'd pull the fuses 1 at a time to determine the circuit. Hope you find it fast.
     
    #3 JimN, Apr 10, 2012
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  4. swishfish

    swishfish New Member

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    Thanks. No after market items that I can visibly see. My next step is to pull the fuses and measure. I will keep posted.
     
    #4 swishfish, Apr 10, 2012
  5. Reagle

    Reagle Junior Member

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    Being post collision, may be check for shorted/damaged wires in the area? You should definitely see tens of mA, not Amps.
    Also, I'd expect something to get a bit warmer at those currents
     
    #5 Reagle, Apr 10, 2012
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  6. mad-dog-one

    mad-dog-one Prius Enthusiast

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    I think RichardAK has got it. Sequentially pull fuses until you isolate the problem to a particular circuit. If you pull more than one at a time, make certain you get them back in the correct spots. Maybe take a close-up color photo of the fuses before you start and have a fire extinguisher at the ready.

    Once you find the correct circuit, look at what it runs and trace the wires to find the culprit. It's got to be a circuit that stays hot when the ignition is off. A combination of patience and luck should do it. After you unravel and this mystery, be prepared to tell the wife how the dealer would have charged at least $40,000 to solve the problem, that you fixed with a toothpick, an old piece of wire, electrical tape, and yankee ingenuity.
     
    #6 mad-dog-one, Apr 10, 2012
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  7. swishfish

    swishfish New Member

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    Looks like my $40,000 check is getting ready.
    EFI No.2 Fuse(10A) is the problem.
    With EFI Fuse - 0.98A to 1A
    EFI Fuse pulled - 0.3A

    :confused:
     
    #7 swishfish, Apr 11, 2012
  8. Britprius

    Britprius Senior Member

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    Well you have found part of the problem but you still have work to do.Pull the EFI relay and replace the fuse if the amps are still at 0.285A it is likely the relay is stuck.

    The battery drain should be 0.015A or close to so keep pulling fuses to find the other 0.285A.

    This does not sound much but it is about 7amp/hr per day, this will take at least 2hrs of running every day to replace.
     
    #8 Britprius, Apr 12, 2012
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  9. swishfish

    swishfish New Member

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    I took it to the dealer. The bottom left last spot just above 'D' is supposed to be left open. But mine had a 15A fuse effectively shorting the circuit. They pulled it out and power dropped to less than 0.1A
    Dealer charged $220 for running the diagnostics.
    Looking back, I did pull that fuse and current dropped to 0.1. But I would have never realized that the fuse should not have been there in the first place. I wish I had a picture from another vehicle to compare.
    Glad it was not a faulty EFI
    Thanks for all your input
     
    #9 swishfish, Apr 14, 2012
  10. hlunde

    hlunde Member

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    So, there is a receptacle for a fuse, but no fuse should be installed there? Is this some sort of test point? Could you possibly supply a photo?
     
    #10 hlunde, Apr 15, 2012
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