I agree that an alternator can charge at idle but a 10si one wire does need excited which is usually about one time to 1000 rpm. So the choke on may get it excited but also may take a rev to excite. Also the one wire will draw about .003 amps even with key off. Not much draw but if stored and with no trickle --it will discharge.
A 3 wire uses the key to exite the diode -- so excited when turned on. Plus the key completely disconnects the diode from the battery.
One wires are for tractors but are cheap and will work on trucks.
