I'm curious about this statement ......................... Today's LiPo chargers turn off when a battery has reached full charge (~4.2v/cell). How does one charge for "too long"?
As an interesting anecdote ...................... A few days ago, I pick up a couple of batteries that a friend forgot at the field just so they don't go missing. Both are the same mah and cell count. One was a low C Turnigy "blue" and the other was a high C Turnigy Heavy Duty. My buddy flies all his batteries the same way and charges them the same way. (Basically, he's not kind to his batteries.) One was puffed and one wasn't. Guess which one was puffed? ;)
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Heat is the killer of all things electric. When a battery is over taxed it will produce a massive amount of heat and that will cause the dreaded puff up. So your best bet is buy the highest C rating you can, run them to about 3.8-3.7v per cell and leave them until you are ready to fly the next time with the pack. Don't recharge them then let them sit. If you do charge them then use them a few days later you will get puffing as well. Make sure you have them at a storage safe level between 3.9-3.7v per cell when you don't plan to use them for more than 3 days unused. As for the puffed batteries, you can still use them for the time being, but you will start seeing loss of performance faster the more you use them. In the end though they will become unusable alot quicker than a battery treated correctly with the steps pointed out above. Also be aware that a lower than adequate C rating pack on a power system designed for more than what the pack can push out will not only hurt your pack but also heat up your esc and motor. So, keep it in mind that also if these are stock batteries that came with a plane, or their "replacement packs", they don't always (or in my experience) ever put a lipo capable of the planes needs. It's only adequate to just fly the plane. That's why those stock packs come out of the plane hot as hell, and after only a few flights the puff comes on.
I hope that helps along with what fhhuber has said. Good luck and happy flying!Leave a comment:
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one of the main causes of puffing is heat.
The higher the charge level, the lower the temp needed to cause puffing.
High current demand with relatively low charge level will heat the packs rapidly.
Quality of the packs will affect when they puff but a full 20C Zippy will puff at appx 140FLeave a comment:
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I'm no expert but in my experience too fast a discharge will cause puff packs. I think this is due to too low an actual C rating versus whats printed on the battery.
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Why do Lipo Batteries "Puff up"
I have never flown batteries to below nominal or charged too fast or too long. Why are they puffed up? Are they useable?
I currently have 3 puffed packs that all readings for total voltage and each cell reads appropriately too. Again, are they usable?
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