Using LI Po Batteries Safely
 

Lithium Polymer Safety Tips: Lithium Polymer cells are a tremendous advance in battery technology for RC use. However, due to the chemistry of lithium cells, there is a possibility of fire if charging is not properly done. It is unavoidable due to the nature of lithium itself. This is no different from many things we use in daily life – knives, kitchen cleaners, automobiles, for a few examples – which are inherently dangerous, but which can be used safely by adhering to simple rules and precautions.

* Batteries should NEVER be left unattended while charging.
* Be absolutely sure that the Lithium Polymer charger settings are correct for the battery pack being charged – both voltage and current settings.
* Lithium Polymer must be CHARGED and STORED in a fire-safe container like a Lipo Sack.
* Do not charge batteries near flammable items or liquids.
* Keep a dry fire extinguisher nearby or a large bucket of dry sand, which is a cheap and effective extinguisher.
* Never charge inside an automobile even when parked.
* KEEP BATTERIES AWAY from children and pets at ALL times.

Lipo fires are a real danger
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thanks! although those are pretty normal safety precautions for any battery

i would like to know though,

what is the usable temperature range for lipos? i mean as in the air temperature whilst being charged, stored or in use?

i have a place that's safe to charge in even unattended (concrete box) but its COLD in winter as its outside, could be in the minus C on some days

Hyperion's info says operating temp for the lipo itself should be above 50F (10C). Their suggestion on storage is 37 - 68F (2 - 20C). I read about people storing them in the freezer at much lower temps and they apparently see no immediate downside. I'd worry much lower storage temps could impact ultimate life though. I store mine in a refrig at ~40F. I give them about 2 days to recover when I remove them before trying to charge/use them again.

I doubt these temp ranges are absolutes, but how much tolerance there is before poss impacting your lipos, I don't know.

Hyperion did mention colder temps could cause an overvoltage condition - something to be aware of.

-----> Do not store your LiPo pack in extreme temperatures below 0C or above 50C.


------> Always store your LiPo pack in a safe and non flammable container away from flammable objects. A LiPo Sack or metal / ceramic storage container is best.

------> Always store your LiPo’s partially charged. They will maintain their performance levels over time and there’s no need to cycle them unless stored for periods longer than 3-6 months.

a lipo sack provides little protection against a fire...