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Car only starts with jump

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Zan Rubin, Apr 17, 2020.

  1. Zan Rubin

    Zan Rubin New Member

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    Four Touring
    Hi all,

    We started having some weird symptoms like the car would start but no dashboard lights, or sometimes the car wouldn't start at all. We replaced the combination meter and the auxilary batter (since it was getting old).

    The car now will not start unless it is jumped. The jump works every time and the car will drive until it is turned off. I drove it for 40 minutes yesterday, checked the voltage on the battery posts and in the front fuse area and both places got ~13.7 while the car was on. As soon as the car is turned off it is totally dead (no lights on dash) and the battery voltage reads about 2v.

    Any ideas? a blown fuse? a short? any help greatly appreciated.

    Thanks!
     
  2. bisco

    bisco cookie crumbler

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    probably a defective 12v. test it at the battery posts with the car off
     
    Mendel Leisk likes this.
  3. IMkenNY

    IMkenNY Im just being nosy

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    Check & clean the battery cable ground to body connection
     
    jerrymildred likes this.
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Check voltage at the battery posts first, then if it's good check cables. Sounds like it's toast though.

    Guessing lots of COVID downtime? We're ALWAYS in COVID mode, being retired. Get a smart charger 3~4 amp range, use it, always.
     
  5. sam spade 2

    sam spade 2 Senior Member

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    If you are indeed reading the battery voltage on the actual posts on the battery.......and not on the cable ends.......BOTH meter leads on the respective battery posts.....then there is really only one possible cause: Your new battery is BAD, or it never was properly charged before installation.

    Now, if you are putting the negative meter lead on chassis metal somewhere away from the actual battery......then you likely have a bad connection at one end of one of the main battery connections. The negative cable where it connects to the frame is the usual suspect.
     
  6. Zan Rubin

    Zan Rubin New Member

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    Four Touring
    Thanks everyone. We'd been driving fairly regularly and the battery is only 5 months old, so I guess I had assumed it was something else, but I brought it back to the shop today, they hooked it up to their fancy battery charger and confirmed that the battery is indeed dead and not able to recharge it. They gave me a new one under warranty, so hopefully the battery was just a dud and not that there's something wrong that's going to kill this one too. I do read 13.9 while the car is on, so seems like the wiring to have it charge is all ok. fingers crossed that everything's fine now.
     
  7. sam spade 2

    sam spade 2 Senior Member

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    Just out of curiosity, what brand of battery was it that failed ?
     
  8. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    What will kill any battery is lack of use. If you're driving very infrequently, say due to COVID restrictions, minimal distances, invest in a smart charger, 3~4 amp range, use it steadily. There's no harm in leaving it plugged in all the time. If you don't, the low level background demands of the car will run it down.

    If charging is not practical in your situation (you're street parking, or in a parking garage with no outlets), the best you can do is to disconnect the negative cable for long down times.