Technical Powermaster Alternator Issue

A few years back I bought a 100 amp powermaster alt because at idle when my electric fan is on my headlights will dim until I rev the motor.

All that time I ran a Delco Alt with no other issues.
Changed the alt and was fine until it only put out 12 volts... So ordered a new regulator and fixed it.
A few months later it started putting out 18 volts so I went back to Delco
The Delco never had an issue unless at idle with the fan in (600 ) rpms or so the headlights go off.
So.. decided to buy a powermaster rebuild kit and rebuild it.
Went fine and was putting out the right volts and all was right
Today went to drive and again putting out 18 volts
The powermaster is chrome
The Delco is back on and with the right volts
So why only with the powermaster would I be having this issue?

 

google powermaster alternator problems
You'll be busy reading for hours

 

I have two Powermaster alternators with never a problem.

 

Call them. They have great customer service. They will take care of you.

 

i see this quite often, "the lights get dim at idle" . thats really pretty normal for a charging system, and really, why would you care? battery is not going to go dead before the light turns green, you dont really need to see anything while your sitting there, ( and the folks in front of you are happy you dont have the f'n lazer beam lights like the new cars), so just drive it! ...ok, i'll shut up now

 

They get more than dim
They go out
I do have 2 good Bosch relays I was going to use
I currently use a JC Whitney brass relay

 

I highly recommend these guys. https://www.mechman.com

 

You may have a battery issue s well, lights giving a little flare from idle not unusual, going out means all your volts went somewhere or the battery is a dud.

 

The engine is still idling fine and the lights go out?
I would go over your connections and verify you have clean tight grounds, as well as the main bond to the body is good.
Also which Delco unit are you using? 10Si is OK but you really need a 12Si or better if you have heavy amperage pull at idle.

 

I swear by my local auto electric shops. I tell them what I want, may have to wait a few days. But their stuff always works.

 

I think the delco one is a 10 SI
i also have an electric fuel pump as well, so that and the fan stay on at idle the lights go dark until I blip the throttle

 

Hate to say this but, no electric fuel pump, no electric fan, no stereo, 30 amp generator, no problems.

 

This is the Delco

 

I'd consider headlight relays and reconfiguring your charging system wiring for better performance. Check these tech pages out.

http://www.madelectrical.com/electrical-tech.shtml



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Sounds to me as though the lights are getting power only from the alternator. Not the battery. Battery SHOULD power lights for several minutes without going dead.

Ben

 

Power for the light relay comes off the hot side of my fuse box and that comes off the other lug of the battery disconnect that also feeds the alt and starter.
I did find the card for the Delco Alt and it puts out 63 amps @ 5000 rpm and 20 at 1500.... The question I have is why am I toasting regulators in the powermaster?
Could the chrome be causing a bad ground?

 

Call em.

 

63 amps isn't a lot when you start piling on accessories that suck up amps.
Factor in the draw from the fan, the draw from the particular lights you have and if they are halogen that can be substantial plus AC or a sound system on top of that. The total may be more than the 63 amps.
Still I am thinking that you have more issues going on than just alternator or alternator output.

 

I’m in the dark on most electrical, and I don’t have an answer for the Alt problems...

...but when it comes to the headlights dimming, and relay wiring, I’ve wrestled with this myself.

Battery disconnects are known to introduce enough resistance in the circuit to drop voltage...

I wonder if the relays are getting the current their designed for...

Any feedback on my reply will be welcome... I’m following the thread hoping to learn more!


Sent from my iPhone using H.A.M.B.

 

20 amps at 1500 is nothing when headlights take 35 alone. This whole problem might be solved with some pulleys to speed up the alternator.
I think the alternator is way too small. That alternator must be running at max output all the time. Buy at least a 100 amp they are cheap.

 

Amen!!

 

If your headlights truly go dark, and the engine continues to run, the alternator is not your problem.
If you can post a schematic of how your car is wired, I can probably help.

 

i am not one of our electrical wizards, but i have some thoughts. first, those battery disconnects are famous for poor connections/voltage drop. i would start there, got a good multi meter? now, burnt regulators. my pickup is an 89 diesel dodge. for the first 6 years i owned it, it would kill a voltage regulator every 6 months or so. they would go to full charge, the amp meter from dodge didnt tell you shit, quite common on these old dodges, some days you could swear it works, other days you think its junk. now, the reason i LIKE a charging system that dims the lights at idle is its a quick -no effort charging test. every time i get in a dark place i like to see the lights brighten up when i raise the throttle off idle, that tells you its all working. so after six years and about 10 regulators i decided to get rid of the whole dodge system and go with a delco 24si which is a one wire, internally regulated thing that all the commercial cummins motors use, and install a real volt meter instead of the unreliable factory amp gauge. sorry, long rant here, but here's the point. when installing my new volt meter i found that the new volt meter in the dash read 2 volts lower than the actual output of the new alternator and battery. after lots of head scratching and meter testing i found that the factory fuse panel had bad connection/voltage drop on the main battery lead that fed my ammeter, and the old regulator. so...the old regulator always thought the battery was 2 volts low, and would try to charge itself to death. so...you are burning up regulators, check the voltage on the trigger wire coming in to the alternator, no such thing as too many grounds, and get rid of the disconnect switch. now to make a long story longer, in my youth i had a 56 bmw motorcycle that had a magneto for spark, and a generator for lights. a few years after i got it running the battery went bad, and i continued to drive it being young dumb and poor. the lights would go off completely at idle, maybe rev up to 800 or so to get dim lights, worked just fine driving down the road. yes, i live in the country so not a big deal, just raise the throttle when traffic was around, but most time i didnt care, and back then know one else did either. long rant ...anybody there yet?

 

Exactly

 

Currently your alternator is more than likely overheating and killing itself trying to keep up with load.

If you have high load components you need a high load sustainable alternator.
10Si were used on carb'd mechanical fuel pump, mechanical cooled GM related vehicles from the mid 70's til early 80's.
When electric fuel pumps(EFI) and fans came online the 10Si was replaced with the 12Si family of alternators.

You need to change to a 12Si 94A alternator, don't get a cheapy knockoff no name brand, get an AC Delco unit so you know you have a proper alternator.

The 94A 12Si will put out 68amps at idle vs the 10Si peak of 63amps.
To maintain your clocking(plug locations) I believe ACDELCO 3342193 is the alternator you will need.
$78+shipping from Rockauto.
94A w 3:00 plug clock. Should be V-belt and leave the disc fan on the alternator as that is critical in keeping the alternator cool. Don't change the 12SI disc for a 10Si fan. Also the 12Si will have a 6mm threaded holes for the ground and the adjuster bolt hole. That is if the new alt doesn't come with either or your existing 10SI is still SAE.

May want to also update your charge wire between alt and battery to a larger gauge. If you are running #10 now you may want to look into a #6, especially if you have the wires on top of the engine. Heat adds resistance, larger wire will reduce the resistance. May want to try and get the wires from directly resting on the (hot)engine.

 

I think you are on to something about the heat....I have a #8 size from alt to battery now.
I’m looking at new ones now

 

One other thing to do to improve your alternators useful power output is to wire the sense wire to the main power bus.

Currently it appears the sense wire(red) is wired directly to the Bat terminal.


10si or 12si, wiring the sense wire to the bat terminal directly is robbing yourself of proper power output to feed your electrical components. It effectively turns your Alt into one wire, which gives poor power response/output for a street car that has several high load(amp) switching components.

A 3 wire alternator needs to monitor electrical load to keep power requirements satisfied. Even with a 10si, bringing that sense wire to the main bus will greatly improve your current power issues.

 

If you are smoking regulators that means the rotor is drawing to many amps of field currant. This is caused by a short in the rotor winding. look up the term ampere turns.

 

So I have it backwards?

 

What are you referring to? I see nothing backwards.

On the back of your alternator there is the large BAT terminal and large charge wire. That should go to charging your battery(+) terminal, sometimes it goes to the main bus of your electrical system, depending on how your vehicle is wired.
Note: Move the insulation of the large wire back onto the ring terminal crimp, there isn't much space there and can easily cause a short if it gets pushed against the case. Normally there is a little button that goes over the BAT terminal to prevent shorting.
Nothing other than the battery charge cable should be on the BAT terminal.(!)

Smaller red wire that is part of the two terminal plug on the side of the alternator.
Red wire is the 'sense' wire, it monitors system voltage. To properly function it needs to be monitoring the main bus voltage, not the alternators(BAT terminal) voltage.
Bring that little red wire out to where you have your electrical loads powered from. Be it the starter solenoid, fuse box feed, or wherever you have your main tap in for electrical power. There should be a singular location of electrical power feed and not multiple taps in the system.

Even with the current 10Si, relocating the 'sense' wire to the main electrical power junction will greatly improve upon your current issues. And this will need to be done regardless if you change to the 12Si or not.

Current 10Si can only put out a max of 63A if it is the high output variant. It also could be a 42A unit which would be grossly under-powering your system.
94A 12Si variant puts out 68A at idle, which will support the cooling fan/fuel pump/lights and other ancillaries at idle.