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12 Volt Battery

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by andyprius, Apr 6, 2012.

  1. stu lb

    stu lb Junior Member

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    At the risk of sounding incredibly naive, is there a "trick" to lifting off the plastic cover to access the 12v battery on the PIP? I want to disconnect/reconnect the negative terminal cable to reset the EV range estimate (mine has gone down from 13.2 or so when new, to 11.1 now (with 1100 miles). I don't want to break anything accessing the battery. Thanks.
     
  2. No trick, Just lift the small panel on the right side and the 12v is underneath. You may have to lift back rear panel first, I don't remember. The nut on the neg lead is facing rearward, which makes it difficult to get to, I changed that.
     
  3. ukr2

    ukr2 Senior Member

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    Stu,

    That is Not a good solution.
    Mine was 13+ when I first got the PIP March 14, but now it's 11.6.
    It's an estimate based on your driving habit.
    Just drive the car. Don't worry about that number.
     
  4. Allannde

    Allannde Just a Senior

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    Like ukr2, I wonder what you will accomplish. I would first drive in EV until HV takes over to see if the estimate and the real range agree. Your real range may not have changed. Further, you can learn the extend your range by being light on the "go pedal" and coasting (instead of powering up to a light and then braking) when you can. Changing the estimate will not change your real range.

    Besides the following will be reset to zero: Average fuel consumption, Distance to empty, Average vehicle speed, EV driving ratio, Clock, Display settings, and the trip meters. But there will be no damage, just inconvenience.
     
  5. bisco

    bisco cookie crumbler

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    since i'll be gone for 5 weeks in feb. and mar., i thought i would check my 12 volt battery health. put a meter on the fuse box jump point under the hood after sitting all night. she read 12.7 volts after almost 3 years. i've never run her down.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    That's really good. Do you drive daily? Helps. Maybe look into a smart charger you can hook up indefinitely, for that long a trip. And/or charge up the battery and then remove it from the car? Or do nothing: seems like one tough battery, lol.
     
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  7. bisco

    bisco cookie crumbler

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    yeah, i don't miss many days, at least 10-15 miles, even if just a scenic drive.:) i've always had good luck just leaving it, this will be the third winter for this one. i've never checked the voltage on any of them before.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah maybe my incessant checks ARE the phantom load. :whistle:
     
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  9. bisco

    bisco cookie crumbler

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    just took a 10 mile ev drive, 13.0 when i got back, and 13.7 when i plugged in.
     
  10. bisco

    bisco cookie crumbler

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    just got back from florida. pip sat in unheated garage for 34 days. 3 year old 12v measured 12.4 with everything off. you can see in post #45 above, it was 12.7 before leaving for florida, so dropped .3 volts in 5 weeks. plugged in the evse, and it's running 13.7, i'll check it again when it's done charging.
    12.7 after charging, i'll check again in the morning.
     
    #50 bisco, Mar 23, 2015
    Last edited: Mar 23, 2015
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    12.4 volts is what I read if the car's been sitting say 3 days. Interesting.
     
  12. bisco

    bisco cookie crumbler

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    but yours is 5 years old? i suppose mine could have gone to 12.4 after 3 days and stayed there.
     
  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah my battery was put in "new" in Nov 2010. Likely sat on a shelf for some time before that. The original battery was dead as a door nail: the car languished on the lot for donkey's ages.
     
  14. bisco

    bisco cookie crumbler

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    that happened to a lot of '10's, sales were really poor then.
     
  15. bisco

    bisco cookie crumbler

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    this is interesting, 12.7 last night after it finished charging, drove to work and back, 15 miles ev, let it sit overnight, and 12.9 volts this morning.:confused:
     
  16. scrappy

    scrappy Active Member

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    When my PIP was about 6 months old, charging would stop after 10-20 minutes and would show 6.7 EV miles available. I'd drive it until it showed 0 EV miles, park the car and not plug in. The next time I'd start the car, it would show 6.7 EV miles available again.
    The symptoms confounded the dealer's mechanics, who called Toyota corporate for advice. Turns out the flaky behavior was corrected by replacing the 12v battery.
     
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  17. bisco

    bisco cookie crumbler

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    wow, that's one i haven't heard before!
     
  18. Pluggo

    Pluggo Senior Member

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    I have not tried jbrad4's method yet but my scangauge shows 11.8 volts half a day after completing a charge on my pip on a 90-degree day. What is the minimum acceptable voltage before the battery should be replaced?
     
  19. bisco

    bisco cookie crumbler

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    12.3, but it's not hard and fast, there seem to be multiple factors in play.

    if that's your stone cold voltage, i would consider replacing it.