Lipo Question

[cave-man]

I have searched on here and other forums and I can't get a specific answer. Hopefully one of you battery guru's can answer.

Why do properly cared for lipo's get a little puffy?

Almost all of my Lipo's eventually get a little puffy. Right now I have 4 Turnigy 2200mah batts, All 4 have been balance charged a equal amount of times and I just noticed 1 is barely starting to swell. These batteries have been cycled about 10 times (charged discharged). The voltage has never gone to low or to high. I store them about half charged.

I have had a lot of different brands and they all seem to do this.

So what causes a properly cared for lipo to swell?

Thanks for the help this is driving me crazy.

Just FYI I am not new to this hobby or lipos.

 

[TexasSP]

Puffing can be due to many factors. Poor cell quality, over discharging, over charging, bad cell, not balancing properly, etc.

What charger are you using? Why kind of cells are these? Do you use a balancer?

 

[cave-man]

Im using a racers edge sure charge 2000 Pro Lipo balance charger. They have never been over discharged or over charged. I balance charge all my Lipos every time and check them when they are done charging.

I don't think it matters but they are all 2s.

Would atmospheric temperature have anything to do with it?

I might of just answered my own question.

I left my house this morning with my batteries, My house was 68 degrees. I took the batteries out of my pickup and took them in the shop with me. I plan on crawling after work so I was getting my things together and thats when I noticed my batt was a little puffy. It is 95 degrees today outside and probally around 90 in the shop.

Out of curiosity I put the puffy Lipo in the freezer for a couple of minutes and now it is back to normal.

Now keep in mind this battery was barely puffy, you couldn't even see it. I could just barely feel it. It felt like there was just a little air traped around the heat shrink.

So does extreme temp change cause Lipo's to act funny like this?

 

[Jkelley]

how puffy are they. Are they dangerous puffy. I run 1800mah 3s turnigy and i do the same as you have stated above. Mine also are a little puffy. I've had mine for a good long time now. I run them in my Scaler and airplanes. They've even had some runs in my old comp crawler, Vxl slash and my old 450 heli. I guess if I would have have been put through that much hell I would puff a little too. Honestly my guess would be the fact that they (no matter how good they are) are made with less than the best quality materials. Could be wrong but the way you say you take care of them sounds spot on so the only thing left could be inferior materials that make up the battery........I still love those cheap SOB's though"thumbsup"

 

[cave-man]

They never get really puffy. I also continue to use mine without any problems. I have had name brand very expensive lipos do it as well as the cheapies. To be honest I have had the best luck with the cheaper ones. I have a lot of lipos for crawlers go fasts, helis and planes, they all seem to do it eventually.

 

[SuperRoo]

It sounds like a charger issue. Have you tried another charger? If your having the same issue with all your batteries then I would suggest that either your lipos are substandard or your charger has an issue.

From what you've said I would consider another charger might be the go.

 

[SuperRoo]

And maybe some new lipo's.

 

[cave-man]

I also have a onyx 230 charger that I very rarely use since it doesnt balance charge. When I use that charger I balance discharge with a common sense RC card. They have never gotten puffy after charging. I am very carefull with my Lipos, I might just be to O.C.D. and there really isn't a problem.

 

[XPLORx4]

What's the C rating of your lipo packs, and what ESC/motor are you using? I've run a 2200mah 3S 20C (30C burst) Turnigy packs on my Axial/FXR/HH Cobalt Puller 7T for ~200-300 discharge/charge cycles, and it's starting to feel a little puffy. Recently it has been taking a really long time to balance, too. I think my motor has exceeded the discharge capacity of the battery too often. I think in a hard bind, the motor draws more than 66 amps, and I've been in hard binds MANY many times.

I have some 25C-35C 2200mah packs ready to run next. They should last longer.

 

[cave-man]

What's the C rating of your lipo packs, and what ESC/motor are you using? I've run a 2200mah 3S 20C (30C burst) Turnigy packs on my Axial/FXR/HH Cobalt Puller 7T for ~200-300 discharge/charge cycles, and it's starting to feel a little puffy. Recently it has been taking a really long time to balance, too. I think my motor has exceeded the discharge capacity of the battery too often. I think in a hard bind, the motor draws more than 66 amps, and I've been in hard binds MANY many times.

I have some 25C-35C 2200mah packs ready to run next. They should last longer.

They are 30-40c and I run them in to different scalers. One has a FXR and the other is a HH torque master esc. The motor in both are Integy 35t

 

[TexasSP]

What you're talking about is not an issue. Slight expansion/contraction is okay. When a cell puffs because it's bad you will know it.

I have been using lipo for 5 years now and seen all sides of them so don't worry, you're good to go!

Also note that the cheaper brand lipo's tend to expand/contract more than the higher end cells. Maxamps however puffs more than any of them I have ever seen.

 

[JohnRobHolmes]

+1 on comments already made here.

To help the longevity of the packs-

Never store them fully charged, always store them at half charge around 3.7 to 3.8v per cell.
Never charge them when cold, the pack should be between 70 to 110f.
charge them at 1c or less.

The packs that I have puffed were due to storing at too high of voltage, or just because they were old. Lipo chemistry has a 2 year shelf life at 70f, although some newer packs may be more stable. Keep in mind that if you charge them cold and then expose them to higher temps, the pack voltage may rise and cause damage. So don't charge in your basement and then let them sit on your dash in the sun!

 

[cave-man]

Thanks guys for the answers. I figured I was worrying for nothing.