Quote:
Originally Posted by Grimm
I recently dismantled 70 some used lithium packs that were going to be thrown away and they were almost perfectly usable. The physical size is a 4/3 A. Digikey has plastic holders for them with terminals, I bought a dozen and I can look at the part number for you if you want. But if you just want a couple hundred cells to play around with they're sitting in a box in my house. I'd be perfectly willing to send them your way, just make me an offer. And I think they're all charged to boot.
For charging I use a Bantam BC8 with a harness I made myself. It charges and balances 8 cells at a time. Not ideal for you, but it does export the data to a computer so you can look at the charging curve.
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Sounds about par for the course.
Laptop batteries are commonly in excessively stupid battery layouts.
Things like 2 2 2 1 (7 cell) 2 2 2 1 1 (8 cell) 2 2 2 2 1 (9 cell).
One can easily guess that the 1's in serial fail LONG before the parallel pairs. And even when they're not and its 2 2 2 2 (proper 8 cell) a random worse battery can often pull a pair weak, and then the other one in the pair fails due to the stress. Although this happens a fair bit less often and usually takes many more cycles unless the initially failed cell was outright defective.
At-least that's what I could figure from the dozen or so I took apart out of curiosity and a little research. Computer hardware is one of my... interests.
Should be interesting to see what kind of C you can pull off these cells without them going up in flame or dieing in very few cycles. Though another problem that may arise is sometimes even same-cell count packs for the same exact model laptop, come in different amp hour ratings, and balancing all the different cells could be... Interesting.
Other note, even if they were charged. Lithies, particularly the ones used in laptops? Bleed rather badly.
Good luck tho be careful. Particularly with any sony cells. They're prone to occational internal contaminants that well, causes them to be extra volatile.