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Post by 900dukess on Jan 26, 2010 8:27:05 GMT 1
A quick question for the lipo battery experts, I was unlucky enough to lose my SC a couple of weeks ago (a story for another day, but I got it back). The battery was left connected overnight and the receiver drained it, as well as the servos chattering a bit. I connected the 3 cell 1500 mah lipo to my swallow ac/dc charger and it indicated that each cell voltage was about 1.7 volts and it wouldn't allow me to charge it. I left the battery in the garage for about two weeks in this discharged state, I was playing around with my charger today and I rechecked this stuffed battery, the charger indicated each cell at about 3.0 volts and it started to charge. I stopped it straight away not wanting a battery explosion. What should I do, try and charge it, or just throw it out. I can't explain why the cells have recovered to 3.0 volts each? Maybe just one of those freaky things!
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Post by Dillzio on Jan 26, 2010 14:45:32 GMT 1
I would suggest that if your balance charger is now accepting it because each cell seems to be within the specified voltage range, then it should be relatively safe, at least as far as using lipos goes (take usual precautions, such as using a flameproof liposafe bag). I would suspect however that you will have reduced the battery's overall life, and charge capacity. I once drained a lipo to way lower than you have, and had to manually charge it with AA batteries before the voltage was high enough for the charger to accept it. The battery ultimately pillowed (swelled up) and I stopped using it. That battery is now the subject of a separate thread: supercubclub.proboards.com/index.cgi?board=sccgeneral&action=display&thread=2770If you have a good battery charger, you can get it to measure how many mah it takes to charge, and discharge the battery. You can use that to test if the battery capacity is close to what it should be and if it is not, you should probably throw it away, or just use it to power your transmitter. I'd recommend investing in a few batteries such as this one: www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6306They're cheap, so if you bugger one up it's not the end of the world, and their high capacity makes them take much longer to go dead. I once had a half dead lipo in a plane that blew away, and the battery lasted over 3 days without going below 3v per cell. |
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Post by patmatgal on Jan 27, 2010 1:56:00 GMT 1
Not an expert here but I'll second that. If you can charge it now go ahead and balance charge it, but it's probably going to have a shorter life than expected . Of the 3 batteries I've revived successfully one started puffing up after 4 flights and is history the other two have 13 and 23 flights on them, one spent 24 hours in a tree and the other spent 16 hours up there.
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Post by badlands on Jan 27, 2010 17:25:00 GMT 1
one spent 24 hours in a tree and the other spent 16 hours up there. lol patmatgal, that made me smile for some reason... |
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