Just a little problem or ?

[baxterday]

Why would you even consider a second battery if the temperature is still above "zero" F.?

Two batteries at Thirty Below, maybe.

Mostly, two batteries are needed when cranking a Diesel, or when using a snow plow that has electric-powered hydraulics to lift and turn the plow.

Because I wanted to. I also run two amps for stereo and subwoofer.