Storing lipos

[alistair.howie]

So, I have some 6s 5Ah lipos which I put on storage charge a few months ago. As they probably won't be used until Spring, can I just leave them the way they are, or should I periodically be putting them on storage charge so my charger will either top-up or take a little charge away as required (if so, how often), or should I be using my charger to cycle them (again, how often)?

Many thanks

[collective itch]

They should hold there charge ok at 3.8v maybe check them every couple of months. No need to cycle them.

[challis349]

just keep them somewhere where the temperature stays about the same, ie not in a shed or garage that will get down to freezing over the winter months, always best to be safe, in an old quality street tin or something, always as safe as possible with lipo's

[Sharpedge]

You could send them to me and I'll fly them for you

Sent from my stupid phone using Tapatalk

[cjcj1949]

It would be a good idea to check them say once a month. As cool as possible. I think between 5 and 10C is best. I don't think freezing is a problem as they don't contain water, but I don't intend finding out. They degrade all the time. The higher the temperature and volts the quicker they die. I would keep the volts between 3.75 and 3.85. If one does drop a lot I would be careful charging it. I would use as low a current as possible to allow the balance current to keep the other cells from charging. Some one did have a fire recently when charging a battery that had one cell that had dropped 0.2V. Lipos are pretty safe though. Not many give problems. But when they do there is a lot of heat and smoke. We had a discusion recently on this forum and my idea of keeping them in a sealed tin was thought a bad idea as if they do go the pressure of gas created could cause an explosion. Lipo bags was the conclusion.

[Randall]

in a lipo bag in a old Army Ammo box, That is a very safe option, TBH a quality street tin will not stop a fire from a lipo. army ammo boxs are not air tight so will allow the gasses to escape and the same applies to the lipobag, If you watch youtube vids lipo bags cope ok but with only 1 lipo in it. who has a lipo bag for one pack ? i store 4 or 5 in each bag one lipo will cause a chain reaction with the next lipo next to it due to heat so a lipo bag will not contain 4 or 5 packs burning away it will just Delay naked flames coming into contact with your home. Get a Metal box to keep them in, it might sound overkill but you will be thankfull if you ever have a lipo failure.

[alistair.howie]

Thanks everyone. I was initially more interested in the voltage issue rather than bags versus ammo tins, etc, but you've now got me thinking. I have 3 such batteries stored in a genuine lipo sac, which is itself in another lipo sac ... and all stored in my living room! The benefit of two lipo sacs is obviously negated by the fact I've got three 5Ah lipos right beside each other. And the benefit of keeping them at a largely constant temperature in my house is presumably negated by the fact that they are ... in my house! I can't see my wife giving up fridge space for them ... but intuitively that sounds like the safest place for them - not because the fridge has a door or anything, but because the temperature is so low. From a technical point of view, if I have good batteries that have been carefully balanced charged at 1C each time, are not puffing and have a low IR, is it physically possible for them to spontaneously ignite if placed in a fridge? Seems to me that the answer would be no, as long as they don't get damaged in the fridge. Even if a single cell were to go bad in the fridge and discharge (is that possible?), there wouldn't be a safety issue until I came to try to charge it, presumably?

[cjcj1949]

I think it's very unlikely to be a problem. We are relying on Chinese Quality control though. The real problem is the energy in the lipos and the number we store. Lipo bags are cheap from China. Most problems seem to happen when the lipos are being charged, discharged or dropped. Or fairly soon after. It can't be that much of a problem though or there would be rules about it, like with storing petrol. I think your fridge is more likely to cause a fire than the lipos inside.

[Brod]

Always store mine at 3.8V in a flight box in the fridge in the shed...with a few tins of beers also to keep them company

[alistair.howie]

Thanks for the information. I put all 3 batteries on my icharger last night, 2 were pretty much spot on at 3.85/6V per cell, but my third one was down to about 3.76V per cell. So I charged it back up to 3.86V and checked the IR which was in the low single digits per cell. So, I guess its just fine and the slight discharge compared to the other batteries "is what it is". All had not been used for 2 months and had about 20 cycles on them.