whats a fair price for "bad" power tool batteries?

Discussion in 'Off-Topic' started by strantor, Apr 6, 2013.

  1. strantor

    Thread Starter AAC Fanatic!

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    I picked up 11 Dewalt XRP 18v batteries at the flea market today for 5$ each, with the mutual understanding that I was paying for non-working batteries.. I was wondering if that seems like a good deal to you guys. I can't find anyone else selling bad batteries to compare prices. New, they cost around 75$.
     
  2. gerty

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    I never intentionally bought bad batteries, so I have no idea what they should go for. I just wonder what you're going to do with so many batteries.
     
  3. THE_RB

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    You can buy new replacement NiCd or NIMh cells from any good battery supplier, then replace the full set of cells in the battery pack and it will be as good as a new battery.

    I'm not sure where or how you would sell the fully reconditioned batteries. OR why you would spend $55 for 11 dead batteries. :)

    If you pull apart the dead batteries you might get enough good cells to make a couple of working ones, although they could hardly be considered "good" batteries if their cells came from series batteries that had dead cells.
     
  4. #12

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    I believe the only thing you bought is education. The remaining cells that work at all have most of their charge/discharge cycles used up and have suffered from improper charging. Go ahead and play "mix&match" to see if you can make one good battery, if you like, but it won't last long.

    One of my mottoes: As long as you're learning from your mistakes, you won't get any objection from me.
     
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  5. strantor

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    That's what I'm trying to evaluate. I have seen videos on youtube saying that you can shock dead packs pack to life with a welder or a few lead acid batteries in series; enough amps and it blows the crystals out of the cells so they take a charge again. I've tried it before with less than shining success (believe I had a thread about it here), but it was on a smaller scale and I think that with 11 packs I will have enough data to assess whether buying dead tool batteries is worth the money or not. 55$ isn't a lot to gamble when you consider the alternative is spending over $1000 for the real thing, new. I'm trying to cobble together a battery pack for an EV project, like a small electric motorcycle. heck, these 11 packs alone, if made to work, could be my entire battery bank.
     
  6. loosewire

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    Batteries has memory ,is that correct ,once they reach a certain of discharge level

    they will always drift back ,a load will take them down quick.
     
  7. loosewire

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    The last hurricane, I went to the box store and purchased three drills and all the bits

    I would need. These were a/c powered ,I got a three way connector on a heavy

    duty drop cord. I,m ready with the power when a hurricane get near ,put them all in

    a bucket....easy to find...easy to carry around. Ever body I know is always running

    out of power on battery operated equipment. Every day construction guys have

    better luck with them,because the drills remember what they did yesterday,not

    last week.
     
  8. t06afre

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    Ah well not so sure about that. If you rebuild battery packs. You must also include proper safety measures equal to those in the original package. Battery packages are regulated in different standards like UL1642 and and UL2054. If you drop fusing and thermal switching. You are in reality sitting on a time bomb. Modern battery packs store a lot of energy. And can with ease start a fire in a badly fault condition
     
  9. GetDeviceInfo

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    Jun 7, 2009
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    buying a liability (disposal) doesn't sound like such a good deal, and play safe when 'shocking' batteries. Don't be jumping from the pan into the fire.
     
  10. gerty

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  11. tracecom

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    Don't you need a spot welder to repack batteries?
     
  12. MrChips

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    No. I have soldered the tabs together or soldered a short piece of connecting wire.
     
  13. t06afre

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    It is most often no problem soldering on batteries if you remove the non solderable alloy with some fine grade sandpaper
     
  14. MrChips

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    Right. I should have mentioned that.
     
  15. spinnaker

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    If the engineers at Boeing can't get it right...


    Spend the $75 and buy a new battery save yourself or your house.
     
  16. gerty

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    On the link I posted they do it for an additional$.20 per cell (both ends)
     
  17. Metalmann

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    When soldering batteries, I use small, diamond, needle files.
    2-4 strokes and you're good.
     
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  18. THE_RB

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    I repaired quite a few professionally when I worked in TV/appliance repair. On a newish battery pack you can replace just the dead cell and they are fine. With old ones (or where there was less distinction between the bad cell and all the good cells) we used to replace the lot.

    Any thermal fuse or current fuse is separate to the cells, so your safety warning is not applicable to a properly done repair or recondition as you just replace cells and leave the rest of the wiring and parts as standard. However thank you for raising the safety point as it is important to leave the safety systems in place. :)
     
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  19. #12

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    Second on the diamond file. A worn out, diamond fingernail file lives on my workbench. It only takes a few scuffs to get a solderable surface.
     
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  20. t06afre

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    Most of the battery packs I have seen/open. Use some kind heat shrinking tube. Around the batteries and the fuses. That can be quite small and thin and hard to notice in the package. So it is easy for the hobbyist. Just to throw away the old package. A friend my replaced his wireless phone. And gave it to his son. He could not get a replacement for the battery pack. So made his own using four heavy duty AA cells just soldering them together with no fuse. After a month the setup caught fire and pretty much melted down. Not so much flames. But a lot of smoke. Luckily this happened during daytime. If this had happen during the night. The outcome could have been fatal.
    The problem here is not skilled people like you doing a battery replacement job. But the mere hobbyist like my friend.
     
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