How puffed is too puffed?

[slipshift]

I was soldering an XT-60 female connector to a battery. I had the male XT-60 plugged in to dissipate the heat and when I removed the plug from the helping hands it brushed the metal. The battery is puffed (I think), I can press the wrapper down less than 1/32". It is a Tunagy and all the others are solid, no give, except for another Turnagy which is almost brand new. So I wonder if the shrink wrap is just a little looser on the Turnagys.

Jim

 

[abieex]

I fly them even if they are slightly puffed and 1/32 isnt even in question for me personally. However, dont take it inside, charge with proper precautions and use a Lipo bag or firesafe enclosure. Don't be overly scared but don't be goofy either! These things are no joke. I think your fine.

 

[slipshift]

Thanks for the quick reply, abieex. The only other battery I puffed was one I left in a tree overnight and it wouldn't take a charge. This one balance charged fine, then I discharged it to storage with no problems. I half expected to get replies like "Throw it away, you'll burn your house down" or "You will put out an eye".

Jim

 

[JimCR120]

Call me a cheap risk taker but for me too puffy is when it no longer fits in the aircraft, no longer powers the aircraft, or has the magic smoke leaking out.

 

[Hai-Lee]

The danger is not in the shape or size of the battery but rather it is in the internal gas pressure build up. I live in a very tropical environment with the occasional temperature extreme and in this last summer it appeared that all of my batteries "puffed" and became relatively high internal resistance whilst not even being used, even at storage charge levels.

I read an old magazine article which stated that Lipo batteries should not be subjected to temperatures over 16 degrees Celsius. The night temp here exceeded that continuously at the time so I started to refrigerate my batteries.

Some of the least damaged batteries seemed to recover but for most it was far too late. I purchased a number of new batteries and refrigerate them before and after charging. So far none of the new batteries has shown any tendency to swell whereas before, the swelling would be noticeable after as little of 5 cycles. It is great to remove a battery from the plane after the flight is finished and it is still quite cool whereas the motor is quite toasty.

Time will tell if this is an answer to my battery issues but it is currently showing great promise. It is still early days though.

Have fun!