Puffed Lipos

[CT]

Question to fellow pilots, what causes a Lipo to puff. I have successfully recharged a puffed Lipo and by the end of charge was back to normal, but I have one now which stays this way even after charge. Taken the advise of Rocketeer and store and charge these outdoors.
CT

[StarHopper]

Re: Puffed Lipos

Howdy.
Cop a squat & watch this: https://www.youtube.com/watch?v=gobFcNzGG9I
It's an entertaining, wide-ranging presentation, & they cover much more of the details than I have time to sit & write out for ya. Should at least touch base on everything you should need to know. Enjoy!

[CT]

Re: Puffed Lipos

Thanks Starhopper,
Very informative!!! Out to buy materials for my bunker
CT

[doctormike]

RE: Puffed Lipos

If you are not going to use a battery for a while, it should be storage charged. This can reduce puffing and make your batteries last longer. You should also check your batteries inner resistance now and then, especially if they are puffing. As inner resistance increases, your flight time decreases. I use an iCharger 106B. It does everything needed to keep an eye on your batteries and maintain them. I store my batteries in metal ammo boxes. Very safe. The Doctor

[WintrSol]

RE: Puffed Lipos

I store my batteries in metal ammo boxes. Very safe. The Doctor

Do those ammo boxes have pressure relief valves? If not, what you have are steel-shelled bombs. If a LiPo chooses to burn, the pressure will increase until the box rips open.

[doctormike]

RE: Puffed Lipos

WintrSol , Yeah, I've considered that, however, I have tried every thing under the sun to make a lipo explode or even burn. They will expell gas when shot with a 22 rifle. That's about it. My main concern is that if one went off in the ammo box , it would ruin $300 worth of good batteries! I really believe an ammo  box would expell gas before exploding. We're talking a steel military issue ammo box, here. All the guys in the Santa Fe club use them and they are considered by very many to be the safest storage. I'll let you know when one blows up! The Doctor  PS. I guess it wouldn't hurt to drill a 1/8" hole in the lid.

[boomer108]

RE: Puffed Lipos

I would have to agree on the ammo box. It was meant to carry a lot of explosive ammo but I never heard of any mishaps. I suppose a vent hole wouldn't hurt. I use a fire proof security box which I think is just as good but I think I will drill a vent hole in just to be safe. 

Roy B.

[WintrSol]

RE: Puffed Lipos

Well, LiPos are a lot safer than many would have you believe, and they mostly light up during the charge process, but there is the, admittedly rare, occasion when they spontaneously combust, releasing a lot of gas and heat. It doesn't matter how strong the steel is, it is still thin enough to split open when the pressure builds enough, especially if one battery triggers ignition in the next. LiPos are made with a liquid fuel, and, if heated enough, will burn; it only takes one in a box to light the rest, and BOOM. Keep them in the cans, but don't latch the cover down tight.

[StormyDog1962]

RE: Puffed Lipos

You can also store them in the concrete blocks that have cavities, place one or two in each cavity and if there should be a mishap it will keep the fire from spreading to the other batteries. Then use the Ammo box to safely transport them. The smaller blocks with cavities are also great to use during the charge process, I also take a couple old ceramic tiles and line my table top with them and put the batteries and charger on top of these. As stated most not all but most incidents occur during the charge process. Discharging a battery too fast can cause the puffing also, so make sure you use a suitable C rated battery for the job.
Best Regards,
Wayne