Just a data point for everyone: at about 37 C in the sun the air conditioning "consumed" 10 km "rated range" in an hour. 10 km "rated range" is about 2 kWh, since "rated range" assumes something close to 190 Wh/km (very roughly 5 km / kWh).
This would of course suggest a 2 kW average load. Which seems about right, if you ask me - 37 C in the sun being cooled to 21 C is a BIG load.
By contrast I would think that a stereo would consume something closer to 100 to 200 W average (at most!), i.e. an order of magnitude less. Not worth worrying about.
