[70Sixter]

Could be alternator/regulator if it discharges while driving.

Interstate batteries are good quality and warranted. If it is defective you should get a new one be reimbursed.

I routinely plug my Box into the battery maintainer when I park. I never know when I'll drive it next. Certainly if not run for a even a week it should be on maintainer.

Batteries hate recharges from low state of charge and will last longer if kept charged.