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XHELI.COM . Autography FlightPower . Advantage Hobby

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Main Discussion > Temporary lipo puffing
 
 
Mavrik1
Senior Heliman
Location: Tucson, Arizona

I have a couple of Imax 20C burst 3S 2200 lipos that temporally puff after a flight. These have the spacers between the cells and the cells are touching after some mild 3D, after they cool, they are only slightly puffed. They didn't do this when I was only hovering. These start loosing their punch about 3/4 of a timed flight.

Is this anything to be concerned about?

The bottom line is having fun.
07-19-2008 09:37 PM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

yes. get rid of them and get some reputable packs... thunder power, flight power, kong power, air thunder, zippy.. although I have no experience with zippy's so I can't speak for them first hand... but they ARE cheap.
07-19-2008 10:29 PM
 
 
Mavrik1
Senior Heliman
Location: Tucson, Arizona

Can you explain why they should be trashed? They don't do this when hovering.

The bottom line is having fun.
07-19-2008 11:30 PM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

The reason why they puff is because they are chemically unstable. If you feel that your helicopter is worth saving money by buying cheap packs, then continue to do so. But if they start to puff and you crash the heli for whatever reason, don't be surprised if the pack ignites.
07-20-2008 12:42 AM
 
 
ginnz
Heliman
Location: Gretna,MB,Canada

i have a couple puffy 2100 mah 3s megapuffer packs ive been flying for months now. i just check the cells ballance everytime i cahrge, theyve gone through 20+ cycles like this, without problems.
07-21-2008 12:16 AM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

ok, play russian roulette with a 600+ dollar investment... if you didn't want advice, you shouldn't have asked.
07-21-2008 08:45 AM
 
 
Footey
Senior Heliman
Location: Hamilton New Zealand

Maybe when you get to 30 flights your battery will have a melt down, make sure you get it on video, I want to see it not read about it.

I had a clown come into my shop today with a LiPo that nearly burned his house down, he was thinking it was a simple warranty thing but I asked to see his charger and it all became clear, NiMh chargers just dont cut off at the right voltage for LiPo batteries. What I am trying to say is they can catch fire and pushing suspect batteries will increase the chance of a fire, you need to follow the recomendations by manufacturers. If you insist on taking the risk for God's sake charge them outside.
07-21-2008 10:37 AM
 
 
tarzan_eb
Senior Heliman
Location: Central Illinois USA

puffed

The reason they puff is over working the battery they are ok in a hover because you are not drawing many amps from the battery or not charging right but the main reason i see for puffing is over amp draw on the battery.I agree with getting rid of them discharge and soak in salt water is how they say to dispose of them correctly.Spend the little extra and buy good quality batteries or you will pay extra later. for quality batteries anyway.

Fly it ! Crash it ! Rebuild it ! Repeat as needed !!
07-21-2008 01:49 PM
 
 
Mavrik1
Senior Heliman
Location: Tucson, Arizona

Thanks, but I was looking for an analysis, not a lecture.

This is what I determined since the OP and in agreement with tarzan on why they puff; A pack will puff if the C rating is lower than the actual discharge rate. The temporary puffing is due to gas expansion from the overdraw heat. If the chemicals have broke down, they would not return. I have a couple of 15C China cheapo's that completely return to the original size after puffing.

My Outrage 25C packs can handle the 3D maneuvers. I'll use the lower C rating for puttering around. Puttering around is better than nothing.

The bottom line is having fun.
07-21-2008 08:01 PM
 
 
Jerry Kirwan
Heliman
Location: RichmondTx

I agree with the above posts in general, but cheap packs do serve a purpose. When people begin in heli's, the cheap packs can be used due to crash damage factor. That is in the first six-twelve months of flying the probability of crash damage is much greater. Now latter after a persons flying improves and the "crash-to-flight" ratio improves invest in name brand packs.

If the packs swell, then go down after they cool they are still usable. If they PUFFFFFF and stay that way get rid of it before it does turn into a roman candle.

Jerry
07-21-2008 08:22 PM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

I hope you have a fire extinguisher... they're cheap to get and for us electric guys that run lipos, it's always a good idea.... I have one myself.
07-21-2008 09:17 PM
 
 
Captain Obvious
New Heliman
Location: Here

I have one with the outer cover puffed up a bit, (permanently) been using it for more than a year like that in a cheap glider. I'll keep using it till it blows up or wears out.

If it was in a 1000$ heli, that might be a very different story.... I'd be a bit more concerned. Still, i think these are a bit tougher than most think.

I pranged one in from 400 feet, nothing useable on the plane... mangled the battery something terrible, but the bat didn't blow up. I did retire that one.
07-21-2008 11:40 PM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

thing about helis is that there's so much inertia with the main blades spinning that the chance of a puncture is much higher... fire extinguisher is a must regardless of lipo quality...
07-22-2008 01:53 AM
 
 
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Main Discussion > Temporary lipo puffing
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