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Would you buy quality, used Li-Ion batteries?

Would you buy used cells? Max you would be willing to pay?

  • Yes

    Votes: 2 15.4%
  • No

    Votes: 7 53.8%
  • <$2

    Votes: 2 15.4%
  • $2 - 3

    Votes: 1 7.7%
  • $3 - 4

    Votes: 1 7.7%
  • $4 - 5

    Votes: 0 0.0%
  • $5 - 6

    Votes: 2 15.4%
  • $6 - 7

    Votes: 0 0.0%
  • $7 -8

    Votes: 0 0.0%
  • >$8 (specify)

    Votes: 0 0.0%

  • Total voters
    13

Dr_Evil

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I might be able to have a good source of used 18650s. They would be from laptop battery packs. It's usually just a few of the cells that go bad. All laptop battery packs I've pulled apart so far have had LG, Sanyo or Panasonic cells. Please vote yes or no and the max you'd be willing to pay per cell.
 



VisibleGreen

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It's funny that you bring this up as I took a part an old laptop battery pack yesterday myself. 6 out of the 9 were still good. The voltages were so low though but they charged and seem to hold it for now.
TBH I wouldn't pay much for used ones.
 

Alaskan

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Thanks for the tip Ped, I bought two of them today.
 

Dr_Evil

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I've extracted over 100 good (3.5v or greater and no damage) cells so far. I could have more if I hadn't messed some up. I still have about 30 packs to tear down at home and there's more where they came from. Each have a minimum of 6 cells. I also have one of those testers on order. So far all of them are LG, Sanyo, Samsung or Panasonic.
 
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VisibleGreen

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I've extracted over 100 good (3.5v or greater and no damage) cells so far. I could have more if I hadn't messed some up. I still have about 30 packs to tear down at home and there's more where they came from. Each have a minimum of 6 cells. I also have one of those testers on order. So far all of them are LG, Sanyo or Panasonic.

I've been thinking of making an E bike. I was going to buy those large 32650 batteries but I think you and I could have a deal here. I could make the battery pack out of your 18650s. I think they're worth buying in large quantities.
Got a price in mind for the 100?
 

Dr_Evil

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I'll have to think about it. I'm not sure I'd go with different brands and capacities in one battery pack though.
 

VisibleGreen

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I'll have to think about it. I'm not sure I'd go with different brands and capacities in one battery pack though.

yeah but I figured I can at least make a cheap battery pack for now and save up for the 32650s later.
It's up to you. Don't you just love harvesting those batteries though? It's like opening a present lol
 

Dr_Evil

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I'm up to around 150 cells now. It's weird. Some packs only have a few dead cells. Others have 0 good cells and some are all good. I wonder if the something went wrong with the circuit board inside the packs with 0 bad cells. I had one with 9 Samsung 2600mAh cells. Every single one was bad.

Pulling them out is the easy part. Careful with a dremel makes quick work of getting rid of the sharp spots on the ends. Getting all the sticky crap and RTV(?) off is a pain.
 
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VisibleGreen

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Yeah the ones I harvested before only had a few bad ones too while the smart charger I bought was able to revive the rest. Yeah I wonder if the board for the dead 9 was bad... is there a way you could test it?
 

Dr_Evil

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Yeah the ones I harvested before only had a few bad ones too while the smart charger I bought was able to revive the rest. Yeah I wonder if the board for the dead 9 was bad... is there a way you could test it?

No way of testing it that I know of. All cells were less than 2v though. Some cells I've pulled out didn't register at all.
 

Pman

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Wonder what the difference is between that tester and my Opus Bt-C300 v2.2 is other than price. That's what I check my cells with and yes I've taken apart a few laptop battery packs and it's not really fun to do although most of what I have recovered were good cells with good capacity.
I wouldn't buy any used ones just because I have a bunch of my own already. If I did it would definately have to be someone I trust and the cells would need to be tested with capacity and internal resistance. Another way I can tell if a battery will hold a charge is to let it sit for a week and reread the voltage to see how much it has dropped. I've had really good cells not even drop .01V.
I think most of mine have ended up being LG with a pinkish/purple wrap at somewhere around 2400 mAh and around 100 for the resistance check but I'm in bed and not actually looking at them (labeled them).

I believe this is the same one:
http://www.ebay.com/itm/5V-Lithium-Li-ion-LiFePO4-NIMH-Battery-Capacity-Tester-Voltage-Detector-Analyzer-/181768021804?hash=item2a5237e72c:g:-78AAOSwcOFWbsAi
Ordered one to check out. Like that it checks LiFePO4 cells.
 
Last edited:

Dr_Evil

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That's the one I bought. Same thing and cheaper since the currency doesn't have to be converted.
 

djQUAN

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If only you were somewhere close. I could use all those protection PCBs. Mainly have a need for the current shunt they use and probably the switching mosfets and thermistors too.
 

Alien Laser

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99% the batteries never go bad what goes bad is the circuit and the transistors,some transistors have a program and date when to terminate the charging making it look like the batteries are bad so company's can make money this is why you recycle batteries. ;)
 




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