i think this is a factual question and not an IMHO question. if not i guess someone will move it.
I like to sit in the car with just the electric power on & listen to the radio sometimes, maybe for 10-20 minutes or so. i know that the alternator recharges the battery when i drive but are standard car batteries designed to be deeply drained (by listening to the radio w/o driving at the same time to recharge) then recharged, or just mildly drained & recharged? Does a deep recharge (taking too much power out of the battery, like 60% or so) then recharging do more damage than a light recharge like taking 10% out then recharging it?