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Anyone scavenge 18650s from old laptop battery packs?

1247 Views 11 Replies 5 Participants Last post by  huskerbuttons
I have a couple of old packs sitting around. I'm aware of the dangers and precautions needed. I would advise anyone that hasn't done it to do a lot of research and never, ever, do it indoors. Li-on battery pack fires can bring down jetliners and their fire-suppression systems are not up to the task so that should tell you how dangerous they can be.

These packs are so old though (10+ years) that I wonder if it's even worth the bother.
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They probably aren't even any good. I deal with computers a lot and laptop battery packs seem to last about 3-5 years MAX under most conditions. I have seen them last even less.
 

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I've harvested 18650's from laptops successfully. Only way you'll know for sure is to pull them and test them. Generally speaking they will be quality cells and in the ones I've pulled there were eight. How well will they hold a charge or how many charges will you get is up in the air. Quality cells can get up to 500 charges. YT has some good videos on safely pulling them.
 

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Discussion Starter · #4 · (Edited)
I've done two packs so far. First was a Dell pack about 15 years old or so. Had 8 18650s, all at zero voltage. Second was a 20 year old Toshiba pack that had 9 Sony 17670s (I didn't even know what 17670s were until I checked) and all tested between 2.2 to 2.5 volts! That's a bit on the low side but I stuck a few in my Nitecore i4 charger and they started charging. They are charging fully in about 3-3.5 hours (they don't even get warm to the touch) and come out at 4.2V. I did some tests with my Quark tactical light and am getting way longer run time than with two RCR-123s and that's after only one charge... it might improve after a few cycles.

I am really amazed 20 year old cells that haven't seen new electrons in probably 17 years still work almost good as new. My next test will be to see how quickly they self-discharge.
 

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Discussion Starter · #5 ·
They probably aren't even any good. I deal with computers a lot and laptop battery packs seem to last about 3-5 years MAX under most conditions. I have seen them last even less.
I've come to the conclusion that most laptop packs "die" simply because the charger and pack controller won't recharge them if the cell voltages are under a certain threshold and they set that threshold way too high. It's either a case of the manufacturers being overly cautious or "planned obsolescence" (probably the latter).
 

· Mr. CISSP, CISA
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I have never taken a power supply apart. Are there screws under the stickers?
 

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I have never taken a power supply apart. Are there screws under the stickers?
For the most part, no. There is likely to by some prying involved. And you'll have to separate the batteries as they'll be wired together. It isn't difficult really, but each type of battery pack will be slightly different on how it's put together. YT has some videos that give the general idea.
 

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Discussion Starter · #8 ·
I was surprised how easy they are to pry apart. It was far easier than opening some clamshell-style packaging.
 

· Mr. CISSP, CISA
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I guess my question is the reverse of what you are trying to do.

If I have a laptop with a bad battery pack, can I pull out the old batteries and put in new.
 

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Discussion Starter · #10 ·
I guess my question is the reverse of what you are trying to do.

If I have a laptop with a bad battery pack, can I pull out the old batteries and put in new.
Not practical for a few reasons:

1) You'd have to be extra careful in prying it apart so you could glue it back together again. Doable I suppose.

2) These cells are pretty expensive. If you had to replace most of them it would probably just be cheaper to buy a new pack.

3) It would be kind of a job removing and resoldering in new cells.

4) Generally when you put a bunch of cells in parallel and series like this they all need to be pretty close in specs and wear. In other words, putting a fresh cell into the rest that are marginal may not work very well, if at all.
 

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Discussion Starter · #11 ·
11 days and the 17670s have only lost .03 volts (4.20->4.17) so I guess they are still in great shape.
 
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