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Can you store a HV battery long term?

Discussion in 'Gen 2 Prius Main Forum' started by StephenJ, Jun 14, 2018.

  1. StephenJ

    StephenJ Member

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    Hey guys, I’ve got access to a wrecked Prius and I’d like to know if I get the battery out of it is it possible to store it somehow to use down the road? I have been considering buying a Prolong charger for my car and I could also use it on this battery to get it balanced.

    What do you guys think? Is it possible to store one and it stay healthy? It’s a 2008 model Prius
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    If you buy the Prolong equipment and charge it up, yes;).

    First you’ll need to see the condition of the battery to determine the next steps :).

    But it is possible (y).
     
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  3. JC91006

    JC91006 Senior Member

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    If you're going to buy the prolong for $700, plus another battery $500?. That is almost the price of a new battery at the wholesale level $1600. Why bother
     
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  4. TMR-JWAP

    TMR-JWAP Senior Member

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    StephenJ,

    It sounds like you're planning well ahead. An alternate option to storage: If you can get the battery cheaply, and seeing that you're not under the gun for time, you may want to go the inexpensive route and get a small hobby charger. You have plenty of time to test each individual module in the pack to find where they're at in regard to capacity. On the 'new' battery, pop off the cover, remove the busbar/wiring harnesses. That should leave you 28 modules clamped together and mounted on the bottom plate. Record each module serial number and it's initial voltage. You can then use the hobby charger to discharge/charge each module. (don't forget to have a fan blowing across the pack for cooling) The initial discharge value is important because it will essentially tell you how much energy that module had stored at the time it was removed from the car. If all 28 initial discharge values are grouped closely, that's a really good thing. Sometimes they'll be spread out all over the place with some modules having 1000mAH and others having 5000. In cases like that, you definitely want to keep an eye on the weaker ones. After you've done 3 or 4 discharge/charge cycles on the modules, you'll know which ones are good and which are weak. Get matching replacement modules and build yourself a kick*** battery. Then put it in your car. Now test all your originals the same way. If your original is better, then put it back in. Whichever you have left that's not installed, you can either build it and sell it, or just sell it/part it out to recoup your $$.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    And as JC said, if you're looking at $1200 for a total, you're way better off getting a battery from a wrecked 2016/2015 for the same $$ or less and just swapping those modules into your pack. Ten years of no worries............
     
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  6. fotomoto

    fotomoto Senior Member

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    Does that mean a free battery? If so, that would make a little more economic sense but if your 09 battery last for several more years because you're proactive and begin grid charging now and not waiting till you have problems then that could mean a lot of effort at trying to keep the donor patient alive. You would also need two harnesses as swapping them out is not advised and would be a real PITA labor wise.
     
  7. JC91006

    JC91006 Senior Member

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    If you really want to be proactive and get your battery situation sorted out, you should start looking for a late model battery 2015+ ($1200). Put this newer battery in your car and sell your old working battery for $500. Your net cost would be the prolong cost. Without the headaches of constantly maintaining your battery again
     
  8. fotomoto

    fotomoto Senior Member

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    Is the case plug n play?
     
  9. JC91006

    JC91006 Senior Member

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    No, you would need to swap the modules if it's not a gen2 battery.

    But there are many gen2 cars with replacement new batteries by now, chances are a wreck might have a newer Toyota battery
     
  10. StephenJ

    StephenJ Member

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    Is there a way I can tell if a battery is the original vs replacement?
     
  11. Raytheeagle

    Raytheeagle Senior Member

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    You’ll have to pull off the cover to the battery and inspect the individual modules for their serial number.

    There is a decoding system and if you search here, you’ll find the method.

    If you’re going to investigate though, pull the orange safety plug for safety.
     
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  12. StephenJ

    StephenJ Member

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    Sorry to bring my post back alive BUT I've got some time to get back into this. So here is the deal I now have this back up HV battery out of a 2008 Prius. I know nothing of its history or if it's good or bad but I do know it's been sitting for a couple years. I have nothing in it so no, I'm not throwing any money away.

    What I'd like to do is determine if its cells are good or not. Then see about charging it. Then see about maintaining it long term....no idea if it's better to sit long term as charged or discharged. BUT while I'm handy with mechanics, I'm not with electrical. I have basic understanding and a volt meter but that's about it. I'll need some good detailed 'how to' on how to test it, how to discharge/charge it, and not sure what kind of charger will be best.

    Also I'm trying to decide if I should just think of it as a full replacement to swap in whenever my current battery dies or if I should just use it as cells to replace cells on mine as they go bad.
     
  13. JC91006

    JC91006 Senior Member

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    If the modules have been sitting that long, you'll have to charge them in order to test them/use them. If you stick them in a car and fire it up, the batteries will probably die a very quick and painful death.
     
  14. Skibob

    Skibob Senior Member

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  15. StephenJ

    StephenJ Member

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    So once the battery has been refurbished and is healthy does anyone have an opinion on how to store it? Should it sit there charged up partially or fully charged? Maybe with a trickle charger on it all the time?
     
  16. bisco

    bisco cookie crumbler

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    i think ni-mh likes a full charge. get a prolong set up.
     
  17. Skibob

    Skibob Senior Member

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    Tough question @2k1Toaster ?
     
  18. Borninblue

    Borninblue Active Member

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    My wife told me the same thing the other day.
     
  19. JC91006

    JC91006 Senior Member

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    When a battery is refurbished, it just means it (hopefully) has been through a thorough inspection, cleaning, and charge/discharge cycles. That "refurbished" term is liberally used and it doesn't really tell you anything about what's been done to the battery.

    Even if a "refurbished" battery has been reconditioned the proper way, it still will lose charge when it sits. The weaker cells will drop voltage much faster than the stronger ones on the pack (it's basically made up of 28 used modules at this point). So you would still need to fully charge the battery after it's been sitting for maybe 3+ months before using it.

    Dorman has a spec for the selling dealers to return the battery to the manufacturer if it hasn't sold in a certain amount of time (since it would be out of balance and discharged). It may be 6 months on Dorman's timeframe, but I would say 3 months is the limit I would let a battery sit before it needing a top end balance (recharge).
     
  20. StephenJ

    StephenJ Member

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    I was looking at threads about 'rebuilding' the HV battery and it says to wire them together in a certain way and let it sit for 24hrs and all the cells will level out to the same and balance out. That sounds like a great way to store them so that they don't all get out of balance.

    I wonder if theres a way that I could wire it up in that balanced way and wire in a trickle charger.