[shovel]

Sorry if this has been discussed already...

I was thinking, what if one installs a relay interrupting the high current charging output of the alternator, so that the circuit is open during normal driving (battery does not charge) but closes when you apply the brakes (triggered by brake light circuit) or any time you turn on the headlights (separate, diode-isolated trigger from headlight circuit)...?

That way you're not charging all the time, the alternator would of course still present "loss" of energy from simply spinning - but would not present an electrical load until the engine's "wasting" power anyway by idling as you brake.

I could be missing something here... but, thoughts?