I picked up 10 free 2 yr old battery packs (4s3p panisonic CGR18650C) that have been kept fully charged and cycled probably less than 10 times. The packs have a built in BMS and a state of charge indicator that reads full on all of them. They came out of defibrillators that by regulation have to be changed at least every 2 years reguardless of condition. I just built an E-bike for my son (36v 500w front hub china e-bay special) like this one. http://cgi.ebay.com/New-Electric-bicycle-kit-36V-500W-E-BIKE-RETROFIT-KITS-/270583036195?cmd=ViewItem&pt=AU_Sport_Cycling_Parts&hash=item3f00017923. I was going to use 12ah sla batteries for the bike when these batteries landed in my lap. Each cell looks like a 2100mah cell. I think they are good for 2C. Would I be better off using new SLA 12ah batteries or would these be good configured for 37v 12ah (10s6p)? here is what the pack looks like before it is opened http://www.master-instruments.com.au/products/60132/M3538A.html
I picked up some free batteries
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StudEbiker
100 kW
One thing you don't mention in your post. How would you plan on charging those Li-Ion AED batts?
John in CR
100 TW
Give the kid the lead and keep the good stuff for your own bike. Research the cells and find out what voltage charger the BMS requires. You'd think that given their intended use, they should be high quality. Regarding the packs themselves, 3p4s is exactly what my Toshiba laptop pack has, so a laptop charger may be the ticket.
dak664
1 kW
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- Aug 17, 2008
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I'd say go for it if you can use the packs without breaking them apart and disconnecting the protection, and that's not likely, the cells may be good for 4 amps but the pack may be less than that, and you'd need 5-10 in parallel for a 20 amp draw. And charging could be a problem, the BMS may refuse a charge without the right digital code being fed to it.
But I've been getting a lot of use from individual CGR17670HC cells cut from old macintosh laptop batteries. I charge to a conservative 4 volts via USB and throw them away if the voltage is too low after use. They have an internal self-resetting thermal fuse for overcurrent and a permanent fuse for overtemperature, but there is nothing to stop them from turning into bottle rockets on thermal runaway, as might happen if they are recharged from less than 2.3 volts. They are great for running LED flashlights, fluorescent lamps, radios, etc.
But I've been getting a lot of use from individual CGR17670HC cells cut from old macintosh laptop batteries. I charge to a conservative 4 volts via USB and throw them away if the voltage is too low after use. They have an internal self-resetting thermal fuse for overcurrent and a permanent fuse for overtemperature, but there is nothing to stop them from turning into bottle rockets on thermal runaway, as might happen if they are recharged from less than 2.3 volts. They are great for running LED flashlights, fluorescent lamps, radios, etc.
Gordo
100 kW
Wow, thanks for the great idea for finding battery packs. 
