So I filled up the tank today for a whopping 49mpg.
Dissapointing to say the least, especially for the first full tank with the alternator-switch. The alternator was switched "off" for about 80% of the tank.
I think that the alternator is never really getting turned completely "off" but rather the switch keeps the alt from jumping up to it's charging voltage of about 13-14 volts.
So, even with the alt-charging switch turned "off" the alt is still charging at 12.5ish volts drawing power. And when it's turned back "on" to 13.5 volts it draws even more power to charge....
So I'm going to start unbelting the alt completely when I can. We'll see if that helps this tank out at all.
Oh, and I weeded out the 2 duds from my 4 batteries. I charged each of them up with my new 12v charger (which rocks btw) and then hooked them up with jumpers to the car and ran the high-beams for 5 min, recording the voltage every 30 seconds or so.
My best battery levels out at 1 minute at 12.1 volts.
My worst battery sank below 11.6 volts within 45 seconds.
And my second worst battery became my best battery after my charger automatically went into de-sulphation mode
