[Willie Krash]

I agree the old Diehards were stellar.
I would think a battery maintainer would fine if left on during winter. As long as it's voltage is controlled I would think battery gassing would not be an issue. In extremely cold climates ought to be helpful. I'm not a battery guy but in old school times you would have to get up around 16v or more to get a battery to gas up, well at least a good battery.