lipos and the cold

[wiseman]

sorry for posting this cos im sure its been asked plenty of times but i cant find a thread regarding my issues. so, can the recent cold snap damage my lipos which i store in my shed inside a tin with the lid on,ive had all my batteries fully charged waiting for the wind and rain to ease off so today was the time to get out on the field but only to find two batteries have now got one cell completely dead

[james_2k]

people recommend keeping your lipos cold when they are being stored.

what is more likely to have done damage is keeping them fully charged, depending on how long they were left.

[Grumpy]

If keeping outside at this time of year you should have them in something sealed, like a zip-lock bag, so the damp cant get to them. A normal tin wont keep the damp out. The cold on it's own should not do any harm, i keep mine in an outside garage inside a fridge and they have been stored that way many months without harm, but they are is a sealed container.

Storing them charged does do long term damage but you wouldn't normally expect to see a single cell go completely.

[trillian]

Just to add to the above, one thing to be mindful of is the temperature in the area when you are charging the LiPos. If you fully charge a LiPo in cool temps then it can go over the max safe voltage when warmed up and damage a cell. You can also damage cells trying to discharge a LiPo in the cold.

[wiseman]

thanks guys, ive had them ready to go with full charge for about 14 days so guessing this is a self inflicted learning curve. bit worried about my others now... sad day

[trillian]

thanks guys, ive had them ready to go with full charge for about 14 days so guessing this is a self inflicted learning curve. bit worried about my others now... sad day

Yeah that's a drag man. I have researched this whole LiPo management thing quite a bit and spoke to some experts and what I came away with is that what causes the most wear on them is if they're fully charged and subjected to temperature changes. Having them fully charged at a constant temp would still put some miles on them but not nearly as much as if they have temperature fluctuations whilst fully charged. I usually don't have the luxury of charging mine the same day I'm flying or at the field so if they're going to sit for a few weeks I put them on a storage charge (ideally about 3.83 volts, roughly 50%) and I try to only go to full charge the day before flying. Mine are also stored indoors so the temperature change is as little as possible.

But I've killed a few over the years as well and then some seem to take so much abuse and keep going.

[Grumpy]

Yeah, i also try to minimise the time spent charged as much as possible. I got myself a powerful charger so i can have my 16 big 6s batteries all charged and ready to go in less than an hour. Charging at the field might be even better but i don't have the facilities for it.

[myxiplx]

Definitely try not to leave LiPo's fully charged. On top of the wear, as posted above if you charge in the cold and they then heat up that's a classic way for them to go over voltage and catch fire, and even without that it will tend to reduce the useful life of your packs.

Check the ones that appear dead, if they got damp it could also be something as simple as a bad connection. See if you can check the cells with a multimeter, but if it's definitely dead then I think it's best to scrap those ones.