Drain AT_BATT from car when reloading electrical object

Gas powered vehicles need storage battery + solar panel,
but should probably be modified to have a ~ 4000 AT_BATT battery
per engine, which recharges via alternator_function() while running.
This implies adding engine starting ( which should fail if the
internal battery is too drained ) and an idle state that generates noise
and CO fumes. This also suggests generators, solar panels, reactors,
and wiring for buildings....todo eventually, when map + item stuff isn't in flux.