ORIGINAL: BocaBen
$5 per cell when you buy 1,200, not bad!
I like seeing them in the plastic bag. I treat mine like explosives, trying to avoid shorts by individually wrapping them. Any explosion so far?
What kind of charger will you use to charge the 32 modules?
Good luck, keep us updated please!
We got the cells used, they were in questionable condition when we got them for $5 each. We had them tested in California in their original configurations, then brought them back and spent HOURS and HOURS going through all of them snapping off the tabs and grinding the surfaces flat.
These cells are completely stable and have metal casing to protect from minor impacts. They are far from explosive! [8D] We actually did completely short a cell out when we were dismantling the original packs, the only thing that happened was that the cell got really hot and the voltage went to zero. They are designed to short out internally instead of exploding if that was even possible. This chemistry DOES NOT allow explosive reactions, that's why they are so great for electric vehicles! Who would want to sit ontop of a huge pack of regular LiPo batteries when they could ride safe with LiFe's??
ALSO,
when they are all loose cells, there's no way to short them out by themselves! Think about it, how would you complete the circuit with two loose cells and nothing else??
We grouped them in bags of 32 for each module we intended to build, it looks kinda getto, but it worked well and helped us know exactly how many modules we had cells for. We needed at least 32, we ended up with 35!
Then we took them all the way to Boulder Colorado to use a special spot welder to weld on the new interconnect materials.
The motor system has an integrated charging system, but we're not sure about the specifics because the manufacturer wouldn't ever get back to us about it. I had recommended finding a charger that could balance charge the whole pack by charging each individual 13.2v module (32 total balanced charges overall). We did find a couple heavy duty chargers that can handle this many cells, but again, the specifics on how that would work with balance charging is uncertian. Alot of big chargers only charge on two leads. At this point battery management is not extremely important because they will not be used over and over and over again, this is more of an experimental set. If it works, our client will be able to get the funding to buy more cells (probably new ones) and hopefully a proper battery management/charging system.