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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Charles Hofacker on March 16, 2016, 09:25:31 AM
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I have two older Arrowind battery packs: 20c/1c, 11.1v 3S1P N-3399mAH. These packs feel like they have expanded from internal pressure. I am afraid they may be history. There are other posts about "puffy" batteries. It's also quite possible that what I'm feeling when I squeeze the pack is nothing more that the plastic wrapping material. A swelled case is an indication of internal failure for dry cell batteries. Is this also true for LiPo batteries? Is it safe to recharge and use these batteries? How can they be tested or checked?
Thanks!
CRH
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Swelled batteries is a sign of badness. It can mean anything from the capacity being slightly down to the battery being ready to burst into flame.
Given how we treat our batteries, we should always store them as if they're ready to burst into flame, so all it should mean is that you shouldn't be surprised if they don't last out a full flight like they used to.
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I put this webpage on our club website for Lipo Battery safety, I store the batteries in a locked case, and charge them inside a fire proof safe.
Sometimes at the nearby RC flying site I see someone charging a Lipo battery with the hood open in their car using the car's 12 volt battery to power the charger...I stay very far away from that situation. If the battery has a problem it will burn then it will burn up the car!
Fred
https://lafayetteesquadrillecl.wordpress.com/lafayette-esquadrille-cl/cl-models/lipo-batteries-and-safety/
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I don't fly lectric for many reasons, but I have a lot of experience with Lithium batteries .If I owned a poly-lite battery I would do as Fred suggests. BTW, a factory rep or lawyer or factory engineer will tell you. "It did NOT explode, it just released it's energy quickly"
yah.....be careful
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wery wery qwickly sez elmer fudd
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If the pack is working, put it in your beater plane and reduce the flight time.
I flew with a swollen battery for a while and once, while testing some props, it shut off on the low voltage cut off. The swollen cell was too low to charge and wouldn't even charge up on the Nimh setting. I saved the battery because it had 3 good cells and a year later I had a cell in another battery go bad. I took a good cell form one and replaced the bad cell in the other and now I have a good battery pack again. If you can solder carefully unwrap the pack and remove the bad cell. Be very careful separating the cells, use a few drops of lighter fluid to soften the glue and make a thin spatula from 1/8 basswood with rounded corners and work very slowly. You don't want to bend or dent the cells.
https://www.youtube.com/watch?v=SVMuaDnsqiA
MM
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I have had a battery short and start swelling. The truth is it was my fault, I wired up a connector backwards. It got very hot and swell quickly. I am sure that if I did not intervene immediately then it would have been worse. When I unplugged the battery the swelling stopped. I let the battery cool down before cutting all the leads off, and soaking overnight in a disposable cup of salt water... sitting on the far side of the driveway.
More excitement than I wanted to have. At least the only loss was the battery.
Phil