12V Battery Drain Causes?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by ArcticPriusC, Feb 9, 2018.

  1. Mendel Leisk

    Mendel Leisk Senior Member

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    Your measurement seems high. On our 2010 Prius I measured parasitic drain under 20 milliamperes, with sporadic spikes to around 40.
     
  2. Mike4kz

    Mike4kz Junior Member

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    Yeah... The only thing - I have a weird amperemeter... Will try another one today, if that one actually screws up a number of digits...

    PS. Yeah. These readings were correct. Got another multimeter with full display - drain gets between 95 and 130 mA. That's really high...

    Update... Based on other readings, I decided to start removing fuses (under the hood) one-by-one. When I removed the fuse for "DOME", the drain dropped from 100 mA down to about 40mA. Removing two fuses called ECU dropped it even more (down to 7-8 mA), but I think it's not a good idea.

    However, I found one "caveat" of this... Now I got "Slip indicator" on all the time. When I put a fuse back, the dome light turns on, "slip warning" turns off, but the drain gets back to 100-130 mA.

    And yes, I checked all lights, they are off when the doors closed. However... thinking back... the light in my trunk is always off. I have to do some more testings if there is anything with either trunk door switch failed, or bulb went off (or shorted)...
     
    #22 Mike4kz, May 3, 2021
    Last edited: May 3, 2021
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  3. bisco

    bisco cookie crumbler

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    has the new battery drained yet?
     
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  4. Mike4kz

    Mike4kz Junior Member

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    No. It is a "higher capacity" battery. And with 120-130 mA it will take a while to drain it completely. However, I'm trying to understand what's going on (and what happened)... As I said, removing the DOME fuse drops drain for about 80-90 mA...
     
  5. bisco

    bisco cookie crumbler

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    is that with the new meter?
     
  6. Mike4kz

    Mike4kz Junior Member

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    I just got a battery in my "more advanced multimeter". Another one gives only two digits after a period, the new one shows three. So, it's more accurate. However, in general, values are about the same (perhaps different "rounding").

    I will check tomorrow, why I don't have a light in the trunk area - not sure if it's just a bulb or the "door switch". All "side doors" switches work fine, the light goes on and off with any door. And light bulb(s), if I remember correctly, take about 1A.

    PS. And thank you for the support. :)
     
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