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12V battery and "normal stamina"?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Viola Palimo, Apr 8, 2012.

  1. Viola Palimo

    Viola Palimo New Member

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    Hello all!

    I'm a new Prius owner (used 2008 with app 70k on it). Had it for a couple of days and decided to detail it since the weather was nice and I had a day off. I opened all doors (causing the inside lights to come on), started the Prius in "aux" mode (pressed start once without pushing the breaks) to get the radio working. I then set the frequency for my favorite channel and started working with the car. After about 45 minutes the Prius gave off 10 or so loud beeps and shut down (not entirely out of power but I sensed something was wrong). I closed all doors and got in to start it up (all the way). I pressed the breaks and then start - and then, nothing... A bit of a "try to spin the start motor kind of a buzz" but really week. Dead 12V.. Would any of you a little bit more experienced users say this is normal behavior. Does it not take more than 45 minutes of radio to kill the car or do I have a "not so good" 12V-pack in the car. Or does a lot of other things power on in "aux"-mode (making me radio enjoyment not so sound)..

    I fixed the situation using a standard (4A max) charger. Took about 2 hours to get enough juice in there to have it start again and then everything was fine, but still. Any "normal" car (with a healthy battery) would easy operate the radio for hours (i've done that many times).

    Comments appreciated!
     
    #1 Viola Palimo, Apr 8, 2012
  2. jdenenberg

    jdenenberg EE Professor

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    #2 jdenenberg, Apr 8, 2012
  3. seilerts

    seilerts Battery Curmudgeon

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    Yes, this is very normal. The 12V battery is the #1 source of component failure. It's capacity is 1/3 to 1/2 that of a normal car, and is often undercharged. The car needs to be driven for about one hour per week to keep up with the quiescent current draw when the car is off. It does not have a conventional alternator and so will not charge up the battery quickly if it has been drained, more like at 3.5 amps like your charger will do. The car will exit Accessory (your "aux") mode after 1 hour to preserve the 12V battery, assuming that it makes it that far, which often it will not, as you have discovered.

    Just leave the car in Ready and you will be fine. Never use Accessory/Aux mode in an older car without monitoring 12V bus voltage because you may have no idea how close to dead the little battery is.
     
    #3 seilerts, Apr 8, 2012
    2 people like this.
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Your 12V battery apparently was marginal at the time you were working on the car. Hence, after running the radio and interior lights for 45 minutes the battery died. You can help the battery by turning off unneeded interior lights.

    2. I suggest that you leave the charger connected overnight to ensure the battery is fully recharged. Although the Prius is starting now, the 12V battery is still seriously depleted if you only charged for two hours at a 4A rate.

    3. If you still have no-start problems then you will need to replace the 12V battery.
     
    #4 Patrick Wong, Apr 8, 2012
  5. Viola Palimo

    Viola Palimo New Member

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    OK. Thanks for your fast input!

    Will do a little more "testing" of the battery and it's stamina before I go about and change it. The car was driven every day for at least a week (more than an hour daily) just before this incident occurred so I believe the "charge state" should have been normal. The day after my failure I drove home (I was at my parents house) and this was a two hour trip (freeway) so I believe the re-charging should be fine (or at least partly done) by now..

    Thinking of putting in one of those Optima batteries. Over $250 in Sweden though so I will browse around a little more before I go ahead and buy.

    Again - thanks for the great community support! Will try to contribute once I have a bit more experience of the car and it's "personality"..
     
    #5 Viola Palimo, Apr 9, 2012
  6. Britprius

    Britprius Senior Member

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    Viola the Optima battery is a good product, but in Europe and Scandinavia we have more choices at 1/4 to 1/3 of the price. For standard fit batteries look at Lucas, Varta, Bosch, and Exide all do Prius batteries at 45amp/hr capacity 10 more than the Optima with 4 or 5 year guaranty , for around £45 UK 475Krona.

    For extreme deep cycle AGM liquid or gell check out invalid mobility batteries, two types fit the Prius perfectly 33 to 35 amp/hr same capacity as the Optima and 55 to 60 amp/hr that is 20 to 25 amp/hr more capacity aprox 55% than the Optima for about 1/3 the price with an expected life span of 8years. Check out Lucas, Haze, Ritar, Platinum, and Yuasa.
     
    #6 Britprius, Apr 10, 2012
  7. KK6PD

    KK6PD _ . _ . / _ _ . _

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    The battery died, RIP! You will have to eventually replace the battery. You can put it off only so long! Hopefully there is an affordable equivalent European battery that is similar to the Optima. Hope you find a good replacement battery soon!

    BTW, Sweden huh?, Welcome to the group! :welcome:
     
    #7 KK6PD, Apr 10, 2012
  8. Viola Palimo

    Viola Palimo New Member

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    As someone predicted - it did eventually (about 4 hours ago) die on me! Darn - had a workshop visit planned for wednesday.. Will have to go out and hunt for a new battery tomorrow. Thanks for the info and tips on euro batteries! All help and advice greatly appreciated!
     
    #8 Viola Palimo, Apr 16, 2012
  9. GrumpyCabbie

    GrumpyCabbie Senior Member

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    I don't think the alternative options are as easy (and as cheap) to find in Europe as they are in the US. Just get a new one from your Toyota dealer - they're not that expensive, especially for the peace of mind a new 12v will bring.

    They have a life of about 4 years use, maybe more if you're careful.

    Oh, and welcome to the forum :welcome:
     
    #9 GrumpyCabbie, Apr 16, 2012
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