Balloning Lipo Cells

[kamikaze89]

What exactly is happening when Lipo cells balloon and what methods do you guys use to reduce/eliminate it? I want my high dollar lipo's to last as long as possible.

Thanks,
Chase

[2walla]

If they are ballooning they are getting too hot-- either they need more cooling air and or you are pulling too many amps. Not recommended for home viewers but...When I get one that is hot, I immediatly dunk it into some ice water. Most of the time if they are still hot they will shrink back to normal.

[kamikaze89]

Great thanks! Is there anyway to reverse this after they have ballooned? Ballooning will lead to decreased performance correct?


Chase

[louu]

first off thanks for your service to this country. lipos arent as dangerous as you think. heres a few things to take care of em. 1. never drop them not even from 1 inch 2. never short them out, if your chainging the plugs cut only 1 wire and put it on the new plug and shrink wrap it then do the other. 3. never re peak charge them, they dont need it and they will catch fire 4. never charge them higher than the c rating meaning if its a 2500 mah pack the absoulte highest amps you can charge it at is 2 and a half amps 2.5 amps if its a 730 mah pack the highest you can charge it is zero point 7 amps. 5. use a charger that is made for lipos with a balancer

[louu]

	Quote: Originally Posted by kamikaze89
	Great thanks! Is there anyway to reverse this after they have ballooned? Ballooning will lead to decreased performance correct? Chase

if a pack ballons, its trash. it could catch fire in your plane and destroy it. and often times when a pack baloons and your flying it around the pack could short out and die completely and then you will have something worse than 1 dead stick you will have no sticks and the plane is goin down like lindsay lohan

[bodywerks]

Over-discharging them will lead to ballooning as well. I also don't recomend hot-charging them - meaning throwing them right on the charger after a flight. Let them cool down to ambient.
Where are you flying in your avitar? Looks kinda like PPRC? I used to be a member there.

[kamikaze89]

Thanks for the tips guys!

That is at Riverside RC in California.

Chase

[Flyer88]

I've been seeing my packs come down a little puffy after a flight and they are never discharged beyond cuttoff ?? After cooling and charging they seem normal again. I wonder if it just the pack producing gas during discharge ? The packs have about 40 flight on them and they still work well.

Flyer88

[Bobbydog]

I was about to say the same thing as Flyer88.. I have a couple packs that puff slightly but return to normal overnight. They still charge normally and I've been using them all summer. Its always the same two Chiniese packs that do it, big surprise If they ever stayed puffed, I'll poke em with a sharp stick. But as long as they shrink back to normal, I'm starting to think that its normal with some packs. Good luck!

Bob

[kiosk]

	Quote: Originally Posted by Flyer88
	I've been seeing my packs come down a little puffy after a flight and they are never discharged beyond cuttoff ?? Flyer88

same here, they have puffed up a bit but not hot or anything, i thinks is definitely overdischarge...but mine dont return back o their original shape but what I do is I compress them "very gnetly / lightly" on a large vise for a few hours....does the trick and havent had any issues doing this for long time....just dont leave unattended or charge while doing this


however i have noticed once you let the voltage drop too low, even just once, they will never be as good, i think thats permanet damage

i have done a lot of stuff with used/old lipos to try to make them explode and catch fire, and man is really hard to get them to ignite or blow up, not as easy as people think.....the most easy way to get them to blow is overcharging, is guaranteed fireworks

[Chalmrast]

Most new lipos under 1000mAh are safe to charge at 3 to 5C with a good charger. Above 1000 mAh charge at no more than 3C. It is best & safest to charge at 1C but that's a little "old school" these days. I fly with a Hyperion rep who charges his lipos at 5C all day long.....

If you have a puffed lipo it is on its way to premature failure. It may not blow up or catch fire, it just won't hold voltage under load, deliver the rated amps, or have the rated capacity.

Storing them in a refrigerator will reduce the puff. But as soon as they're charged & used, they'll puff again.

I've had lipos puff because I left them in a fully charged state too long! 3.85V per cell is the best storage voltage.

[wawsha]

I have never run into any sort of issues with lipo packs. I flew my blade 400 3 times a day for nearly a year with one pack and it performs like the day i got it. Even with my cheap knock off brand ebay batteries i havn't run into any issues as of yet. I think i probably just jinxed myself.

[phippsj]

To answer your original question: The ballooning is due to off-gasing of the lipo layers due to over-amping or over-charging the packs. A puffed up pack is a ruined pack. It may last a few more charge cycles, but you are asking for a battery failure or fire.

The best thing to prevent the puffing is get a good quality charger made specifically for lipo & li-ion batteries. Use a cell balancer if it's not already built-in to the charger.

I had this problem on some small 2 cell lipo packs when I charged them on a Hobbico Accue-cycle field charger. It had a lipo setting, but the charger was so cheap and simple, it just never kicked off when it should. It ruined nicad and nimh packs for me as well.

I finally wised-up and bought a good quality Sommer Minron charger. It's pricey, but will charge all types of batteries. I use a seperate cell balancer between it and my Chinese lipos (aren't they all?) No puffy or hot batteries.

[kiosk]

	Quote: Originally Posted by phippsj
	The ballooning is due to off-gasing of the lipo layers due to over-amping or over-charging the packs.

does same apply to over-amping on discharge? I have always charged mine at 1C and with a Cellpro10s lipo charger and always a balancer....yet they have puffed on discharge (because I am to "throttle happy!")

[classclown]

I have never puffed a lipo yet in the 5 years I've been playing with them. When you set up a model, do the math before you buy the equipment, props, matched to the kit weight. Look at the numbers, and you will know if the setup is good.