In sci.chem.electrochem.battery jtaylor wrote:
Got a diesel, and it gets cold here. There's a block heater, but I also
have a 1A charger that could be attached to the same extension cord - would
there be any drawback/problems with leaving this connected (on the battery
side) _all_ the time? It's a cheapo transformer & diode unit.

It's probably not a good idea.
It may eventually cook the battery.

I know my local stores are selling 24 hour timers for the equivalent of
4$cn.
Put it on for an hour a day, and problem solved.

In cold weather - batteries discharge slower.
At -10C, 1/8th (or so) the rate at 20C.