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I am saying that the alternator batt output should be fed directly to the 12 battery, not through any relay. (just like on a regular car setup).

If the under dash switch wants to be eliminated, then that fine. The issue here is the relays them selves.

You need 12v to trigger a 12v relay. 6 volts to trigger a 6volt relay. If you got a high amp 6v relay, I don't see a problem running 12v on the switched side as the contacts should be beefy enough to handle it. Just running 12v to the trigger side is going to fry the trigger circuit.

Perhaps I should just draw this out really quick.

Hope this make more sense. This is without an under dash switch using the ignition to trigger the 12v system on, and also excite the alternator. Not sure what your ground polarity is but as the basic diagram is the same regardless.

Use this one instead. Realized I had my relay pin out rotated 90 degrees.

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IIRC alternators are grounded to the engine. Therefore the alternator with a DIRECT wire to + post of 12v battery is hot all of the time. When ign sw is OFF the 12v battery current must be completely disconnected from everything including the alt.

Run alt OUTput wire to #87 terminal on RELAY. What's wrong with that???

Altho u are rite, the output terminal of alt is ALWAYS hot on most production cars.

Keith, go check any car from about 1970 to the present, respectfully you are incorrect.

The battery and the Alternator BATT terminal are wired together, and are not switched. The regulator for alternator controls everything.

Check any aftermarket wiring diagram and you will see the same.

Most run from the battery to the starter BATT lug, and from that same lug to the Alternator, or where ever the common always hot connection junction block is. For reference, here is a system diagram from a Chevy:

Terminal 1 is the exciter which also acts as the feed for the idiot light. When there is 12v on that, it activates regulator.

Terminal 2 is the voltage sensing terminal and is what the regulator uses to control output based on battery/system voltage.

The Batt terminal is the output. While it is technically hot because it is connected to the battery, but it is not charging unless the regulator says so.

I went out and checked my Samurai alternator and 89 Caprice. Heavy output wire is hot with out starting or turning any switches. BUT, what i have noticed on the Samurai alternator set up that the RELATIVELY SMALL MC battery looses at least 2 volts charge very fast over just 3 or 4 days of nonuse. Down to 9 volts in less than 2 weeks.

The old 6v with generator seemed to hold a charge a long time. My 56 Exec with generator shows no voltage at the gen terminals. only 12v at the external regulator.

The small motysickle battery mite be drawn down real fast if alt is always hot between a week or two of operations. BIG battery not as fast draw down.

I'm not sure. But is there any reason NOT to connect alt output to output side of relay instead of direct to battery post???

Sound to me like the Samurai alternator has the exicter wire always hot, which is keeping the regulator energized, and that is drawing the parasitic load you are seeing. Either that, or there is something else in the car the is bleeding off the voltage. A sweep with a good multimeter should be able to pinpoint the culprit.

I'm not sure, but it seems to me that alternators have a very tiny but constant current draw (maybe in milliamps or something) even when car is just parked and abandoned.

They shouldn't if the car is wired correctly. Most modern cars have a constant low draw because of things like clocks, radio memory, computer, etc. But that has nothing to do with the alternator.

Also this is why I avoid the 1-wire alternators. Give me a 3-wire one any day. There is a reason that GM has used them for decades.