Jump started 2007 Prius, but not sure which battery was bad...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by LauraM, Jan 13, 2013.

  1. LauraM

    LauraM New Member

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    I'm a PriusChat newbie with a question I can't seem to find a direct answer to from what I've read so far on the forums. I bought my 2007 Prius used in 2010, and have had almost no problems with it since. I don't drive it much (live in the city and mostly take public transport to work), so the mileage is low still (around 44,000 miles). I currently keep it in a garage, and was recently out of town for a couple of weeks. When I returned, I used it once to run a quick errand (less than a mile roundtrip) - no problems. The next time I tried to start it, several of the dashboard indicators came on and it wouldn't start. Turned it off, and on again, and this time nothing happened - no lights, nothing. Couldn't lock it either. I read a bunch on this forum that seemed to indicate it might be the 12v battery, so we thought of having my husband check and replace the 12V, but after some thinking, decided to try AAA first to see what jump starting would do.

    We called AAA and the tow guy (who fortunately had experience with hybrids) jumped it from the main (hybrid) battery. Wish he would've checked the voltage of both batteries first, but he didn't have the equipment to do that (plus from what I understand, it's a bit of a chore to even get to the 12V). Anyway, after the jump start, it started right away, good as new. We drove around and kept it on for about 2 hours (as recommended by a few people on this forum and by the tow guy), then parked (on the street this time, just in case) and turned it off. Then waited three hours, and went out and tried it again - started just fine, good as new; no indicator lights coming on to indicate an issue with any system.

    So my question is, which battery was likely dead and required the jump start to get going again? And what should we do now - hope it's fine for a while? Try to recharge one of them? Take it to a shop or Car Zone to have them test the charge on both batteries? Or go to the dealership to get it looked at just in case? Pardon my ignorance of how the batteries are connected. I know you can charge the 12V (which I understand runs the electronics) from the main battery, but I don't know what it means in terms of which battery was the problem, if we were able to jump started it from the main battery and now it works.

    Thank you thank you in advance for any help with this!!
     
    #1 LauraM, Jan 13, 2013
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Not even your Toyota dealer has a charger for the big High Voltage battery. So I am assuming that the tow truck driver jumped the 12 volt battery. There are jump points under the hood so he does not need to get under the hatch area to do this. Whether he used the jumpers in front or back, he was charging the 12 volt battery.

    If you have not replaced the original 12 battery, it has had a good 5 year run and this may be time to get a new one if it causes you the least bit of further problem. Better to put a new one in some sunny saturday afternoon than late some rainy night.

    Optima DS46B24R Optima battery direct fit replacement for Prius 2004 + with Instructions
     
    #2 JimboPalmer, Jan 13, 2013
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  3. SteveLee

    SteveLee Active Member

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    Agreed. It most likely had to be the 12V that caused the problem and was jumped by AAA. You could go through the volt testing and charging process but like Jimbo said, if the battery is over 4 years old it is nearing the end of it's expected life and has now been weakened by being so low. Better to replace it at your convenience than its next failure.
     
    #3 SteveLee, Jan 14, 2013
  4. LauraM

    LauraM New Member

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    Great - thanks to both of you for replying so quickly and explaining the situation. It is the original battery, so I guess it's gone beyond the call of duty lasting over 5 years. After checking the price of replacing it at the local dealership ($370), we'll probably opt for the do-it-yourself kit as recommended by Jimbo.

    Thanks again so much!
     
    #4 LauraM, Jan 14, 2013
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  5. SteveLee

    SteveLee Active Member

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    If you can find the replacement at an auto parts store they will often install for free. If they have to order it it may be in the next day or even by that afternoon. But have them check the volts before installing. A fully charged 12V should be 12.8V and 12V is roughly 50% state of charge. New doesn't always mean fully charged. They lose charge sitting on the shelf.
     
    #5 SteveLee, Jan 14, 2013
  6. richard schumacher

    richard schumacher shortbus driver

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    I'm guessing that you don't have the Owner's Manual for this car? Get a copy from a dealer or online and read it. It's full of stuff you need to know. Also get a copy of Toyota's (not a dealer's!) Scheduled Maintenance Guide; one place is here:
    Toyota Online Owners Manuals and Service Manuals

    For example, the manual tells about the 12V jumpstart and test point under the hood, which is easy to access.
     
    #6 richard schumacher, Jan 17, 2013
  7. edthefox5

    edthefox5 Senior Member

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    Good You got lucky.

    The fact that the tow truck driver didn't know about the front jump points would have scared me. But you didn't know. Shows this was his first Prius experience. So many reports of AAA drivers damaging the car by a reverse polarity jump. I would imagine trying to hook up jump cables to the 12 in the back with its limited reach and poorly lit would make an accident quite easy. Jump starting the 12 is the Prius Achilles heel. So expensive if gone wrong.

    Go with the Optima. You can buy it online at Autozone and pick it up locally at there store. Mine was $169.99 online.
     
    #7 edthefox5, Jan 17, 2013
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