How long does a typical car battery last when used to power construction tools?
Obviously it depends on the power consumption of the particular power tools you use, and how you use them. A typical car battery (70AH), fully charged from the solar panel over weekdays, usually lasts me a weekend of work. That includes the use of a variety of power tools (drill/driver, jig saw, circular saw), as well as reasonable use of indoor and outdoor lighting at night. (See separate topical page on Small Cabin Power Sources).