100 amp Powermaster Alternator in a Pinto

I'm putting a 100 amp Powermaster internally regulated alternator (8-47101) in an 80 Pinto. I've been researching the installation over the past few days. I want to make sure I wire it up properly when it comes in.

1. Using solenoid post as primary junction - Is this the best option?
2. 4 awg wire from alternator to solenoid post - This is good for a 100 amp alternator, correct? It should be under 10 ft long - the battery is in the stock location on the opposite side of the motor. What size fuse do I want here?
3. wire from solenoid post to battery - Stock looks like 10 or 12g, should I go to a larger gauge? I don't need this section fused, right? I've read that it's good to limit voltage flow to avoid charging the battery too fast if it happens to get drained. What's the best way to do this? It seems like it would be unsafe to do this by using a smaller gauge wire, is it?
4. from solenoid post to fuse panel - What size fuse do I want here? 50 amp? I'm not adding much to this over the factory draw - just a CB and a couple small things.
5. I also have a newer 200 watt Polk Audio amp with I believe 10 awg wire and a 20 amp fuse - this is currently hooked up to the solenoid post and has a built in relay that goes to the switched interior power. Just listing it as it's another draw on the system.
6. The alternator supports the factory idiot light. I have read that I need a diode in here to prevent back-feeding when the engine is shut off?
7. I don't want to use fusible links because they can't be replaced on the road easily. Are fuses or breakers better? I read on here that a breaker mimics the function of a fusible link better.


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The 4 awg is plenty to the post from the alternator

The 10 or 12 from the battery to solenoid is NOT ideal. You need thick as possible, Id say at least 8, 6 or 4 awg from the battery. Yes back in the day the smaller wire was "ok" but dont forget that the battery supplies everything and also has to crank the motor. There should be a good fat wire from the battery to the starter post. If you have only a 10 on there now then you're pulling a lot through there to the fuse box, stereo etc. its a weak spot.

Limiting battery charging is untrue. With the "sense" wire from the alternator your alternator will only put out as much as the battery needs to stay charged.

Solenoid to fuse panel is up to you so long as the wire itself is stronger than the fuse. 50amp is way big enough. Usually if you hook up high power stereos you take power directly from the battery itself and NOT through the fuse box so the 50amp isnt in the picture at that point.

5 - That Polk Audio Amp is what I just mentioned above and is wired correctly. The relay draws little amps but connects the Polk to your battery directly (through the post on the starter) which is why I think you want LARGER than 10awg from the battery to the post. Your battery to POST should be fatter than anything it feeds. Its like a water supply line feeding all other things

6 - you dont need a diode its just and added thing to go bad. Idiot light is needed though

7 - I prefer BIG FUSES to fuseable links or breakers. Breakers could get stuck, links can catch fire (which is what theyre supposed to do) but theyre annoying

You might want to invest $20 or so in a 12v distribution block. Most audio cars have them. Its just a huge chunk of metal with bolts for 0,2,4,6 awg wire connections. Basically you mount it on a fender or wheel well and run the battery to that instead of the post on the starter. From there you can connect everything and it also shows the voltage of the battery in LCD which will show 12v-15v depending on the alternator charging status.

MAD Electrical says alternators can put out too much amperage when a battery is low - like when you jump start the car with a dead battery. And it can kill the alternator and battery - which I've experienced. I'd like to prevent damage if I do have to jump it and charge with the alt down the road. The voltage sensing in the Powermaster alternator is at the voltage regulator itself, not remote by the way.



The idiot light is not needed with the alternator according to Powermaster - it's able to be used as a 1 wire, which I don't want to do, or a 2 wire. I want the ignition to turn it on and not have to rev the engine and I do want the idiot light - the two go hand in hand anyways.

Definitely planning on a distribution block down the road, but I'm thinking the solenoid post should be fine for now. Stock wire from the solenoid to the starter should be fine still right?

The powermaster is a 10si alternator, 3 wire, which they also can be used as 1 wire. Youre correct that as a 1 wire it needs to spin at about 1000rpm to turn itself on "if" you dont use the idiot light.

The idiot light and 1 wire are unrelated. You need the idiot light to turn the alternator "on" so that it outputs. The idiot light goes back to your ignition switch essentially

MAD knows their stuff but if youre going to install a "limiting" wire for the charge output then you also compromise the output ability of the alternator at all times, including when you have everything running (head lights, stereo blasting, electric pumps etc). Its never great to charge a dead battery with the alternator but sometimes the reality is that its necessary. Alternators are built stronger these days and so are batteries. No its not ideal but I cant see limiting the alternator just for the few times that a dead charge is needed.

Your wires will be fine, Im just giving ideal sizes.

I thought with a one wire that the alternator is switched on purely by the pulley spinning and there is no connection to the ignition switch - am I wrong there?

I want to use it as a 2/3 wire regardless. Powermaster told me that it does not support remote voltage sensing - which is what I believe the 3rd wire in a 3 wire system is for. But there are in fact 2 spade terminals on the alternator in addition to the power output. I know one of the 2 is for the idiot light/ignition switch. I thought the other was normally for remote voltage sensing - so was I given incorrect information about the remote voltage sensing?

And in theory, if I do have to charge the battery off the alt, could I keep a spare battery terminal with a thinner wire with me and connect that to the junction until the battery is charged in place of the 4 awg I plan to use?

Thanks.

You're correct about the 1 wire, it turns on by rotation and no idiot light needed

I would think powermaster is more knowledgeable about their product than I am but I thought all their alts were both 1 or 3 wire. I have a powermaster 140 setup as 3 wire. If the terminals are there then it will perform as a 3 wire since the terminals are part of the circuit. Otherwise, there would be an empty space and no terminals

As for dead battery charging: a smaller wire will only help when it burns itself up. Lol. Simply put, a dead battery and an alternator charge are not the best mix. Alternators are for sustaining a full charge, not a dead charge. A fully dead battery really needs an overnight trickle charge at home. In the real world we DO jump start a dead car and drive it. Alternators are built stronger than the old days as are batteries so I think a few dead charges won't kill anything. Too much will overheat both. I don't think a wire is going to make the difference really. I've never seen a car with a "dead charge wire" that you describe but that doesn't me it won't work. Maybe someone else has more info

You should double check with powermaster about that 1 wire alt. When I bought my 140 alt I thought everything I looked at was 3 wire but promoted as a 1 wire. I went with a 140amp only for the idle output amps but the 100 amp is all I need overall.

Jegs told me it supported 1 wire or 3 wire usage. I've also read the same elsewhere. I called Powermaster, and they said it doesn't support remote voltage sensing, but it does support the idiot light and ignition switch. Maybe the guy I talked to was wrong about the voltage sensing, the alternator does in fact have 2 terminals on the side. Either way I'm not overly concerned about the remote voltage sensing but I'd still like to know.

Got it all wired up and working last night, thanks for the help. The only thing I didn't take into account was the electric choke heater, but that was solved by running a wire inside to the fuse panel for switched 12v+.

was it a 3 wire like jegs said?

I'm not sure. It has 3 connectors, but Powermaster only told me what two of them do. The idiot light/alt turn on and the power output. I don't know what the 3rd is and I'm going to call soon to find out. It should be for external voltage regulation, but they said it doesn't support that.

It's the regulator voltage sense wire. I think they're mistaken about it not working, use it to get the most out of the alternator

That's what I thought. I just sent them an email for clarification. I'd like to use it if it will in fact function, but there is minimal voltage drop measured at the battery. I think around 0.1 or 0.2v, I'll take a reading this weekend with the amp and headlights on and see how the drop is.

This is the reply I got.

They said it was there so a factory GM harness can be plugged into the voltage regulator as they put the same one in their GM alts.

Here's why it's needed and why, if the terminals are there then the regulator is also there:
http://www.madelectrical.com/electr...gesensing.shtml