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Ugh, I think my 12V battery's dying

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Tideland Prius, Apr 2, 2008.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    I parked at the grocery store today and listened to the radio for about 30 mins while waiting for my mum.

    I then decided to go in so I go to IG-ON to wind up the window and I get the red triangle of death. I turn the car off, wind up my window and shut off my lights (it was dusk and the headlights were on in AUTO mode). I opened the door and got a "Key-in-ignition" chime despite the fact that my key was in the pocket.

    Fiddled around and cycle'd and finally got it behaving again.

    Came back to the car 5-10 mins later and loaded up the trunk. When I sat inside, I played with the headlight switch. The "taillight on" light was barely illuminating. Something can't be right. I turn the headlights to full on. They seem dim and the screen flickered. I pulled to flash the high beams, still dim and the radio shut off and turn itself on again.

    Ugh... it was then I realised that the battery was running low so I decided to start the car while I can. Headlights went to full brightness, MFD brightened up a bit and the "taillight on" light came back to full intensity.

    Servicing on Sat, I'll have them check the condition of the 12V battery.
     
  2. 05 Solar Prius

    05 Solar Prius New Member

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    just had mine replaced. went to dealer and was told $175. it was under warranty so it was free. not stocked by every dealer so i would have them check if it is in before you go. Kragen is $89.00. is it under warr?
     
  3. richard schumacher

    richard schumacher shortbus driver

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    The battery is dying because you're killing it. It's a small battery and can't run any accessories for more than a few minutes. If you want to run any accessories for more than five minutes leave the car ON and in Park and let it manage its own energy state, as it was designed to do. The only time you should not do this is when the car is inside a building or other completely enclosed space without no provision for exhaust removal, in which case you'll have to suffer without the radio, lights, and A/C.
     
  4. Winston

    Winston Member

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    I second what Richard says. Don't ever use your car battery for listening to the radio more than a couple minutes in any car. Your battery will last much longer.
     
  5. efusco

    efusco Moderator Emeritus
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    I disagree with you both. While the battery is not huge it's not exactly tiny either. The dimensions are relatively comparable to other small cars. I've routinely run my basic electronics for 15-30 minutes and my original battery lasted over 4 years.
    We're not talking about a couple D-cell batteries and a high drain...very very little energy is required to run the radio in ACC mode and 30 minutes should be fine. The only reason Jon had any issues is b/c his battery is at the end of it's life cycle.
     
  6. mingoglia

    mingoglia Member

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    I agree. However, with my Prius I tend to leave the vehicle on as was mentioned earlier. I don't do this because I'm afraid of the 12v battery giving up the ghost as much as I do it because sitting for relatively short periods of time the car is going to be on battery anyway so I figure I'd just let it do it's thing and as someone else put it allow the car to manage it's on power. Besides, In AZ it's nice to have the A/C running. :) Although I bought my '08 towards the end of the hot season last year I have had it in the low 100 degree weather and was pleasantly surprised how long the Prius will run on battery with the A/C on parked. :)

    Mike

    Mike
     
  7. Winston

    Winston Member

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    Four years is not very long for a car battery. My cheap oem batteries in other cars last 7-8 years. Car batteries are not made to be charged and discharged. That would be a "deep cycle" battery. Deep cycle batteries are constructed much different than a standard car battery. Plate dimensions, thickness, clearance from bottom of the battery case, etc.

    Car batteries are happiest being fully charged all the time.

    OTOH, it is not some sort of crisis if you partially discharge your battery periodically. However, it WILL decrease its life.
     
  8. mingoglia

    mingoglia Member

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    You are correct about contrasting the difference between starting batteries and deep cycle batteries. However, 30 minutes of listening to the radio won't run down a battery in good condition enough to make this a problem.

    I'm not sure what part of the country you're in but in parts that have extreme temperatures 3-4 years is doing pretty well. Heck 2 years here in Arizona where it's still 104F at 2am (and upwards of 120F during the day) is good.
     
  9. patsparks

    patsparks An Aussie perspective

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    Quick run get a grain of salt.
    Personally I don't mess about with batteries, if they go flat with little provocation they get replaced. No point having a $20,000 car if your stuck because of a $100 battery.

    Different story if I leave a light on all night, I will recharge but if it goes flat or seems to be going flat with little draw, recycle time.
     
  10. dacarls

    dacarls New Member

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    Re: My 12V battery died- how to jump?

    My 6 month old new battery (2008 car) died - for no reason? Its totally dead. How to jump? Nothing works. The manual says pull off the fusebox cover - then a cover - presumably the little red one with a +. NO negative ground is obvious. Ground Anywhere? And has the main battery set also been discharged? Is it damaged? Where could all that voltage have gone?
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Re: My 12V battery died- how to jump?

    Find unpainted body metal to connect the negative lead to. For example, the head of a bolt.

    The traction battery (what you call the main battery) should be unaffected by the 12V auxiliary battery being discharged.

    As to why the 12V battery died - if you didn't leave a cabin light on, is it possible that you are not driving the car enough? The charging voltage is ~13.8V, which is less than that found on conventional automobiles with alternators. If your driving pattern is mostly very short trips combined with periods of non-use, then the battery may not remain fully charged.
     
  12. efusco

    efusco Moderator Emeritus
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    I NEVER said a think about deep cycling or depleting. I said I listen to the radio for 30 minutes which you say never to do. In ACC mode I estimate around 0.5amp draw for the radio and any other stuff that powers up in ACC mode. I defy you to show that 30 minutes of listening to music on occasion will shorten the life of the battery in any measurable way. I'm quite confident in saying that the various 'stand by' drains including the SKS and such sitting over night put a much deeper cycle on the battery than my 30 minutes of music.
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The 2G Prius 12V auxiliary battery has an AH rating in the low 30's. When in ACC mode with the stereo on, my guess is that ~1A, maybe 2A current is required. So you could play the radio for several hours before depleting half of the battery's capacity.

    However if the battery is not fully-charged, or through aging has lost some of its original capacity, then you might have a surprise.
     
  14. Spectra

    Spectra Amphi-Prius

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    This brings up a question I hadn't thought of, in 2 months of Prius ownership:

    While the battery of a traditional car tells you when it's low, (by requiring longer cranking) -- how can one know when the Prius 12V is low? Does the ICE not kick in correctly at ~ 7-seconds after start-up?
     
  15. richard schumacher

    richard schumacher shortbus driver

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    It seems that the most common symptoms are the dash and/or MFD going nuts during or immediately after booting up the car, or failure of the car to enter the "Ready" state.
     
  16. Tideland Prius

    Tideland Prius Moderator of the North
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    Not basic but still under powertrain (do not know if the battery is under powertrain lol)

    LOL. funny. 30 mins will NOT drain the battery to the point that the headlights look dim. I've had it in ACC for 2 hours and the headlights are at full brightness (have to turn on twice cause it auto-shuts off after 1hr). The radio uses very little battery.
     
  17. 05 Solar Prius

    05 Solar Prius New Member

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    :loco:

    The dealer said that the 12 volt is only covered by the 3 year bumper to bumper. Not part of the power train!:usa:
     
  18. philmcneal

    philmcneal Taxi!

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    - have ready mode for 30 mins
    - remove surface charge
    - put a volt meter up on that b****ch
    - what's the minimum voltage before discarding?
    - call me up instead of the stealership ;)
     
  19. xsmatt81

    xsmatt81 non-AARP Member

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    does anyone know if Optmia has/will ever make a prius style battery? I have a red top in my honda and it's been goin strong for 5 years now. The car has a system also, can run off bat no problems for an hour, although it's been a while since i ran it like that.

    would be niceee. the panasonic look's so dinky

    also if anyone want's to answer this question, what kind of charger can one use? I read something about 3.5A max on trickle. What brand charger can i pick up? I have a black and decker already--but I think it pushes more like 9 A
     
  20. Tideland Prius

    Tideland Prius Moderator of the North
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    Don't have a volt meter in the house. :pout: