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Old 03-09-2012, 10:00 AM   #156
Anorak
Woolf Barnato
 
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Joined: Jul 2004
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Quote:
Originally Posted by _cy_ View Post
assuming you are referring to two cell lithium cobalt 7.4 battery pack

procedure to recover lithium cobalt (4.2v max 3.7v nominal) is to charge at .01C until volt raises above 3.25v per cell. then charge rate .5C to hopefully full recovery.

recovered many a li-ion cell this method with Schulze isl 6-330d .. the new Powerlab 8 is hugely more capable. they call it a battery workstation instead of a charger for good reason.

charged many a lithium cobalt battery inside my fireplace insert with 1/4in steel construction. fireplace was the safest spot in the house. greatest danger from using li-ion (lithium cobalt) cells occurs during charging. lithium cobalt chemistry will accept a charge until thermal runaway (explosion) occurs at about 4.35v. this is why it's very important to only charge lithium cobalt cells with a charger that terminates charge at 4.2v. above link is from an article I wrote five years ago on Candlepower forums



no Shorai isn't A123 .. but both use LiFePO4 chemistry. Shorai uses four flat prismatic cells wired in series, different size of prismatic cells are used to achieve desired amp hour rating. Ballistic and SYCL uses cylindrical A123 cells wired in series. then paralleled to desired amp hour rating. currently there are only about 12 different mfg of lithium cells in the world.

plans are to drill in later, advantages and disadvantages of prismatic vs cylindrical LiFePO4 cells
A123 is a unique chemistry as compared to other LiFePo. I accidentally overcharged four in series until they fail. There was a "pop" and some smelly steam. A friend tested a cell at 130 amps until it failed. After about 30 seconds the smoke came out and it fell apart. No comparison to LiPo or lithium cobalt.
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