battery types

A normal car battery (lead-acid) isn't designed to be discharged very much. It's designed for very-short-term surge applications, not for running things overnight.

A deep-cycle battery (AKA marine battery) is designed to handle a load for hours at a time.

(though note that the term "deep-cycle battery" has been overused as a sales term, and doesn't always mean that it's a true deep-cycle battery)

cutoff percentage