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Dead 12v battery

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MikeDee, Aug 20, 2014.

  1. MikeDee

    MikeDee Senior Member

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    My 12v battery is dead (left the door ajar). The rear hatch is locked, so I can't get the the battery from there. Can I attach a portable battery charger to the jump points in the engine compartment? I want to charge the battery with a battery charger rather than getting the car started and driving it around wasting gas.
     
  2. bisco

    bisco cookie crumbler

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    yes, make sure you use a smart trickle charger of the right sort. and you're better off, driving it around isn't that effective. now that you've killed it, you're going to have to keep a closer eye on it in the future.
     
  3. IMkenNY

    IMkenNY Im just being nosy

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    I installed low current draw led bulbs in the doors, map & dome lights to make up for the small 12v battery we have in the Prius.
    I paid less than $10 for all of them on Ebay .
    Hopefully interior led lighting will be standard in the next generation.
     
  4. MikeDee

    MikeDee Senior Member

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    I don't have a trickle charger (just a standard battery charger). Toyota should put in a timer that kills all power to the lights after a period of time to prevent a dead battery.
     
  5. MikeDee

    MikeDee Senior Member

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    I think I'll just jump start it from my other car. My battery charger is an old manual one and probably puts out too many amps. Don't want to risk damage.

    Question: should the other car I'm jumping from have its engine on or off? I would think off as it shouldn't take much to start the Prius and seems the safer way to go.
     
    #5 MikeDee, Aug 20, 2014
    Last edited: Aug 20, 2014
  6. fuzzy1

    fuzzy1 Senior Member

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    ^^ With the other car, LEAVE THE ENGINE OFF!!!

    Does your manual battery charger have several settings, such as a 2 Amp setting? Such low current should be OK.

    Or crawl into the trunk area and use the mechanical hatch release inside. This is awkward, but do-able. Then you can remove the battery and safely charge it outside the car.

    I changed all my interior lights to low current LED versions, allowing 5X to 10X more time to discover such a problem before the battery goes dead. This doesn't eliminate dead batteries, but should allow errors to go overnight without killing it.
     
  7. Easy Rider 2

    Easy Rider 2 Senior Member

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    If the capacity of the "old" charger is 6 amps or less, it will be just fine for a short term charge.
    About 10 minutes will probably be enough to get it to start.

    If, just as an example, the battery is rated at 12 Amp/hours, connecting a 6 amp charger for two or 3 hours should give it near to a full charge and there will be no real danger involved. The current the charger delivers goes down as the battery charge goes up.
     
  8. szgabor

    szgabor Active Member

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    6 Amp is too high !!! maybe the 10 minutes is OK but NO way to put it on for 3 hours !!! I think the manual says less then 4.2Amp
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Get yourself some sort of smart charger with capacity 4 amp or a bit less, hook it up at the engine bay fuse box (follow hookup instructions carefully), leave it on till it indicates it's done and the battery is ok.

    If it never gets there it's time for a new battery.
     
  10. MikeDee

    MikeDee Senior Member

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    I jumped the car and drove it for a while. Seems ok. The clock needed to be reset. Radio presets didn't change. Anything else that has to be reset?

    What are the part numbers for the LED bulbs? Great idea for all my vehicles.

    My old school Schumaker manual charger was 10 amps; no lower amp setting so I didn't use it. Time for a new one.
     
    #10 MikeDee, Aug 20, 2014
    Last edited: Aug 20, 2014
  11. bisco

    bisco cookie crumbler

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    windows okay?
     
  12. bisco

    bisco cookie crumbler

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    this timer thing is a brilliant idea.(y)
     
  13. KayakerNC

    KayakerNC Member

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    In mine, the clock went to midnight, the A & B trips reset to zero, and the auto temp had to be reset.
     
  14. Roland1555

    Roland1555 Senior Member

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    Glad you got it started again fine.

    Keep in mind, that having the battery go flat can damage it, more damage the more often it happens.

    You can get a little smart charger like a Ctek which they say is smart enough to safely charge the battery back up, and desulfate it.

    You can connect to the charge points under the hood or the battery terminals themselves in the back of the car. The way the Prius charges the 12 volt battery is such that this little charger is something that you might want to hook up every month or so depending on how often and for how long your drive the car to keep the 12 volt in good health over the years.

    Roland
     
  15. MikeDee

    MikeDee Senior Member

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    I found a neat tip to prevent the problem; always lock the car, even when in your own garage. I'm going to try that from now on.

    Also, I've been reading that LED lighting can cause RF interference affecting radio reception. Any comments on that?

    Is the Ctek 7002 a good model?
     
  16. retired4999

    retired4999 Prius driver since 2005

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    When you get a new charger, hook it up and fully charge your battery. Just to make sure it is fully charged!
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Not sure. Just a quick glance at it's spec, max amperage is 7, which is more than the 4 amp you want. Not sure if it could be run at lower amperage? Also, seems kind of pricey at suggested retail $149.

    I'm using CTEK 3300, which may be a bit out of date now, but it's the one that's still commonly available locally. Was $60 something when I bought, on sale. There might be a similar model, same 4 amp range, with a bit more bells-and-whistles, now.

    Yeah, looking locally, I see now CTEK 3300 for $69, or CTEK multi us 4.3 for $79. Assume the latter is 4.3 amp. The 3300 is tried-and-true. ;)
     
  18. Easy Rider 2

    Easy Rider 2 Senior Member

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    What model Prius and what page in the manual.
    I don't believe that I have EVER seen the capacity of a battery charger specified in TENTHS of an amp.
     
  19. fuzzy1

    fuzzy1 Senior Member

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    Pages 434 and 567 of my 2012 Prius Three manual list a maximum charge rate of 5 amps.

    I remember seeing the 4.2 amp limit in print. But because of Toyota's wonderfully concise Index, I can't find it now. It might have been in the manual for my previous 2010 Prius-II instead.
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Found this on page 563 of my pdf of the 2010 Owners Manual:

    Capture.JPG
     
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