1. Attachments are working again! Check out this thread for more details and to report any other bugs.

How to tell if HV battery in wrecked car is good

Discussion in 'Generation 1 Prius Discussion' started by ronlewis, Jul 16, 2020.

  1. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    There's a wrecked Prius for sale that I'm thinking about buying to salvage the HV battery. Is there some easy way to check whether it's "likely" good - maybe using a voltmeter? I don't have access to take it apart. How about at the plug through the trunk? Anywhere else? I'm assuming that since it was driving while wrecked, the battery is/was good recently.
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Use the serial number from the case, or the serial numbers on the modules to decode the date of manufacture. If it's an original 2001-2003 battery, I would pass.

    The sticker should be on the very end of the battery where the cables connect.
     
  3. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    Thanks, but that won't help. The auction isn't going to let me disassemble anything. And, yeah, no one wants an original battery, but it is highly unlikely this high-mileage car is one. I think I'm looking for somewhere I can test with a voltmeter. The car doesn't turn on, I'm sure.

    Can't I lift up the back cover and access the disconnect plug? I could just touch my voltmeter to the two terminals?
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    The two terminals of the safety plug will give no reading. There's no path of continuity at the other end of the circuit.
     
  5. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    5,596
    3,770
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    My experience with insurance auctions is the cars often sit for months before reaching the actual auction date; the epidemic has only slowed things down more.

    GOOD LUCK!
     
  6. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    Well, I tried that. Touched my voltmeter to the two prongs on the disconnect plug. It said 54V - arrgh, I think. Not sure what setting my voltmeter was on. But, I don't guess it could be 540V, or 5.4V, so I expect that's right. Is that an accurate measurement of the battery's SOC?

    The auction cars have typically been sitting for 6-8 weeks. What do y'all think the chances are that the battery can be charged up?
     
  7. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    6,690
    6,381
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    Bid like it's bad, smile if you get one that tests good anyway.

    The thing with car auctions is that you do not go bid on a car. You keep going, and eventually you get what you need.
     
  8. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    Oops, posted before logging in again and didn't see y'alls replies. OK, so that didn't tell me anything, dammit. And, yeah, the car has probably been there awhile, and you're right, Doug, they sit sometimes because the auction company is getting the title in their name (some are just consigned by the original owner and don't have to wait for a title), and the pandemic has slowed that process down.

    Well, dang it, I gotta think some of the auction cars still have good HV batteries - you can buy them with warranties from LKQ - one of the biggest dismantlers. I'll see what it goes for. Wrecked badly, so shouldn't cost much.
     
  9. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    I'd kinda agree with you, and I've bought a bunch of auction cars. I definitely go to the auctions with a small number of target vehicles, even just one. But, I don't make an emotional decision. I have a price I'm willing to pay before it starts, and I don't get caught up in the process.

    In general, you always pay more than anyone else is willing to pay - or else you wouldn't win the auction. But, guys like me/us have, IMHO, an advantage in that we're only looking for one car and can be choosy. Since my business model is to actually use the cars (unless I'm buying a parts car only), I don't mind paying a little more than the body shops/used car dealers/dismantlers who need to make a good profit but have more overhead. I get a ROI by driving the car for a while, and if I can sell it for more than I got in it - whoopee. And, my record is great at that. Haven't lost money on one yet, except the one I blew up. Sometimes I only make a little profit, but I've also scored quite a few times (examples: invested $300, sold for $6000; invested $4000, sold for $10,000, invested $4000, put 160k miles on it before it got stolen).

    Thought I was the only "coalroller" here, lol. I always say that these Prii balance out my carbon footprint from my trucks.
     
  10. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    So, what does it mean? As stated above, the auction car gave me that 54V reading at the disconnect plug, which doesn't mean anything according to TMR, but just for kicks, I measure the one of my running car and, like TMR said, it registered 0v. So, why is the auction car saying 54v?

    Just trying to decide whether to buy that car, and looking for any clue that the battery might be good.
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Think back to one of the Gen 1 batteries you've previously disassembled. One end of the battery has a negative cable and one end of the battery has a positive cable. Each goes to a main relay, where it is open circuited. With the disconnect switch installed, you'll read ~280ish volts at the main relays. What happens when you remove the safety disconnect? You no longer have a path of continuity from the neg relay to the pos relay, so you lose the voltage reading.

    The disconnect switch cables are connected to two adjacent modules on the non-sensor harness side of the battery. Once the disconnect is removed, that becomes an open circuit. You now have 2 open circuits in the battery circuit. There is no continuity, at all, to take a voltage measurement. unless..........wait for it.........there is so much electrolyte leakage on multiple modules, that it's actually providing a continuity path between 54 volts worth of modules.
     
  12. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    Thanks, TMR. I figured it meant something. So, there's no way to tell the actual voltage, if the car won't start?
     
  13. AzusaPrius

    AzusaPrius Senior Member

    Joined:
    May 27, 2020
    1,639
    766
    0
    Location:
    California
    Vehicle:
    2010 Prius
    Model:
    IV
    You would have to be able to open the battery case and test each cell.
     
  14. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    damn. Thanks, Az. Did you ever meet Roy and Dale there in Apple Valley?
     
  15. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Techstream, if they'll let you connect up and it has 12v power. Or maybe they'll let you plug in a bluetooth OBD and use one of the Prius appps to look at the modules.
     
  16. AzusaPrius

    AzusaPrius Senior Member

    Joined:
    May 27, 2020
    1,639
    766
    0
    Location:
    California
    Vehicle:
    2010 Prius
    Model:
    IV
    I passed by them today actually lol
    Their final resting place is up the street from me.
    That strip of road is perfect to stretch the prius out and get her juices flowing.
     
    ronlewis likes this.
  17. ronlewis

    ronlewis Active Member

    Joined:
    Dec 5, 2016
    797
    166
    1
    Location:
    texas
    Vehicle:
    2001 Prius
    Model:
    One
    OK, thanks. I doubt they'll let me hook up, and I doubt it has any 12v. I'll have to think about this one. There's not much of value left on the car from the wreck, which is why it should go real cheap.