[Filligree]

That's backwards. At too low temperatures batteries start to take damage during discharge or (especially) charge, so 0C is the lowest temperature at which you should charge it. 5C would be better.

It's a concern mainly for e.g. offgrid batteries being used in the winter.

[stavros]

I know, but "as cool as possible (up to zero degrees C at least)" is conflicting, and kind of means "below zero degrees".