Yes, if you really want to be certain NOT to get disabled somewhere,
hopefully you'll be able to call the AAA, get the charging system
checked out and replace the alternator and battery right now. The
alternator and battery work together and a bad alternator will cause
the battery to be depleted and go dead. New car batteries cannot
easily recover from a deep discharge, it destroys the battery.
Marine batteries can withstand a deep discharge... They are
designed to do this, but, NOT so with a car battery, they are
different technology. A fully functional electrical system on your
car should not have any degradation at all no matter how many
systems are running, A/C, radio, power equipment, 12 volt
charging of Dometic cooler, etc. They all can be running
simultaneously, if you are at full power. Finally, even if you don't
run any of these systems, your car's engine needs electrical power,
so, when the alternator finally dies, the engine will tap all the
electric power it needs from the battery and once the battery can't
deliver, you will be in trouble. Hey, you're driving a Lexus... Don't
tell me you can't afford to get this done???