Battery storage

[Fullmetalarmour]

As you can see i live in Sweden and January to Mars it can be very cold as low as -20 celsius how do i put the battery on storage? The fc40 charger don't have a storage mode.

 

[Mandrake]

Leave them in a small insulated bag / box and charge them up once a month .

 

[Fullmetalarmour]

Thanks hopfully there will be "warmer" days like -2