I am having a problem with my battery going dead after about 48 hours with the master switch off. The battery is a new Optima Red Top and the alternator is a Powermaster one wire set up. I wired the alternator with a 6 gauge wire to the positive side of the master switch. I have had both the battery and the alternator tested and both tested ok. Could the internal regulator be pulling power while the car is off? At first I thought that my master switch could be bad as it was old. But after replacing it I am still having problems. Any help would be greatly appreciated!

Simply disconnect the negative battery cable from the battery and install a test light with a bulb in between the battery cable that you just disconnected and the battery terminal. Make sure your test light is NOT an LED, it has to be an actual regular test light bulb. If there is a current draw/drain, the bulb will be illuminated. You mentioned that the alternator is connected to the battery side of the on/off switch which normally means that the rest of the cars electrical system is seperated from the positive side of the on/off switch. Now, disconnect the alternator and see if the test light goes out. If in fact that the alternator is the ONLY component on that side of the on/off switch which is turned off and the light is illuminated, that would tell me that the alternator is drawing too much current. If the light is still on after the the alternator is disconnected, there is something else on the circuit drawing current. Anyways, the old light bulb installed in line with the NEGATIVE battery cable always does the trick for most. I use an ammeter installed inline for minor current drains. If the light is bright, I never use my ammeter; only if the light is dim. Try that out and see how it goes for ya.

Oh and by the way, I have heard that alot of the 1 wire alternators will draw current at all times. How much I dont know. There are some GM alternators that require a small 12 volt trigger wire that basically tells the alternator to turn on internally, those dont drain the battery. I believe the one like you have is basically "turned on" at all times. I do things different than most, I dont wire my alternator to the B+ side of the switch. But I also use a 4 post battery on/off switch and I use the two small terminals for my MSD ignition trigger wire. That way, when the on/off switch is switched off, it works the same way as you turning off the ignition switch but it also seperates the battery from the ENTIRE electrical system also. You wont have a battery drain problem unless there is a on/off switch problem or a battery problem. Just my 2 cents.

Thanks for the info. I will try that out and see what happens, but I have a feeling that you are correct about it being constantly "on". I have also left a message with Powermaster to see what they have to say