You need to cycle an electric fan with a thermostat, and even though the electric fan is not driven directly by a belt connected to the engine, it is driven by the alternator which is driven by a belt.

The battery doesn't actually drive any electrical components unless the engine is off and then when you start the engine the alteranator must make up the deficit in the battery so the net is less than 0 because the alternator is not 100% efficient.

Please forgive my wordiness.