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Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
its not super puffy, and my RC shops have shown me ones that are like potatoes ! I should post a picture... anyway, ill dump it properly after I use it to validate my safety and warning circuits, and ill need your guys' input for that.
I have found full-time work in this crap economy, so ill have more money bet less time for all this, but hey, better than freeloading off mom and dad
-- im thinking of an op-amp driven piezo for audible warning, first a low volt chirp, then a continouos wail for "land now or youll be sorry". (variable Volt detect is needed, via a pot.)
-- then I need a safety "e-stop" for the compitetion rules, that cuases the battery to be disconnected, and a full crash-in...
both the above features need to be integrated into a single small board, and the "e-stop" be operated via Xbee/zigbee radio.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
I'd be cautious, like others said letting the gas out also lets damp room air in, and LiPF6 + H2O = HF (!)
Also any water in the cell will generate lots more gases, and potentially destabilise the electrolyte further.
EDIT: The consensus on the endless-sphere forums is that ANY amount of puffing means the cell has severe internal damage and could internally short and ignite with little or no warning even at Voc of 3.7V ; any cell which smells of acetone or peachy should also be treated as damaged and not used even if it measures fine.
YOU SHOULD NOT USE THIS CELL FOR ANYTHING!! (sorry for shouting, but people have lost their houses to LiPo fires even when packs are in storage days or weeks after being last used)
See Some people have had success de-puffing cells but it is a really really bad idea (tm) as once the cell is open to air corrosion can occur and lead to an internal short at full charge. See
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protecting LiPo's from deep discharge...
