One more thing, I've had several 1 wire alts, that when wired to the system in any configuration that leaves them connected to the battery draw current when the engine is off. Most times it's milliamps, other times a couple amps. I have had them kill the battery before. This was most pronounced when the car drew more than the alt could produce, and the voltage at the batt was low. Could be that having the charger connected while running, and other abuse, but either way it did it.

I use a 250 amp can relay that closes the circuit with a switch. The whole circuit is on the control side of the kill to insure it cannot run on after the kill is off.

I know it's more wiring, and possibly unnecessary, but if I have diodes fail in the alt, or whatever may cause this drain i can kill it too. Not to mention if you need that extra round winning .0001 sec, not dragging the alt might help, unless the 5 ounce relay weight cancels the power gain lol