[brillo_76]

Originally Posted by 19963.4lsr5

The factory fogs are part of the lighting system. I wonder if the polarity is messing it up since I went from from a switched negative to a more common switched positive.

The coil resistance of the new harness could also be a problem. The factory setup used the bulb filament as part of the circuit to control the high beam indicator. I notice the high beam indicator is more dim than before. I’ll try an wrap my head around it in the next week or so. I’m keeping as it is and will deal with it as time goes bye. Worse case I will need to switch off the fogs when I switch to high beam.


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I think your close. OEM is negative switched. Try a load resistors where the element would be. By switching to positive switched I suspecting your losing your ground..

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[19963.4lsr5]

I tried different ways to try and isolate the two different headlight systems. No dice.

I had an ignition circuit handy so I used that circuit to energize the fog relay. It was a cheep punt for now. I’ll work on getting a low beam wire to the fog switch in the dash.

As for the smaller pulley on the Alt it looks like the smaller 50mm pulley increases the output by 2-3 amps. If I turn off the fogs the voltage holds steady at 13.23 to 13.28v and doesn’t drop. This is for the 70a alternator.

I could replace the brake lights with LED and that should let me keep the fogs on.

This test cost me 26 dollars. I tried putting the pulley on the 80a Alt but the shaft size is 17mm.


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[jdlover14]

Should definitely be a cool build, I’m following

[19963.4lsr5]

Are my headlights brighter? I think so....

I like having the fogs on the ign circuit. My fogs stay on for high beam to help me see deer and go off with the key.

It’s dark going to work and coming home.

I’m happy with the 50mm pulley it’s almost able to handle everything at 600rpm. Much better than before seeing it quickly going down to 12.5v. Now it hovers at 12.7-12.8 and if I turn off the fogs (4.6a load) the voltage jumps up to 13.2-13.3. It’s good enough I don’t hear my fan slow down and see my headlights dimming.

This 70a Alt has an aftermarket voltage regulator and may behave differently that the stock 80a I removed. I’m still going to look for a 48mm pulley in a 17mm shaft size just to see if there is any difference.


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[19963.4lsr5]

Here is the 50mm pulley I used to speed up my Alt.


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[19963.4lsr5]

Yesterday it was 19f and I had a bearing squeal. I assumed it was the AC idler pulley and replaced it today with a part from autozone. It said made in America with a Taiwan bearing.

The old part had 285k miles on it. And I wasn’t waiting to order it from the dealer.

Edit: the old part was a Duracrap autozone pulley like I just bought. Exact same bearing pressed into it.

I’ll try and find a USA, Japan, or German bearing to press into the pulley.





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[19963.4lsr5]

Today I went over the headlight wiring harness and added a low beam wire to run to my fog light switch.

The wires going to the bulbs are 16awg my clamp on amp meter shown almost 8a so each bulb pulls around 4a. I have a .08v drop from the relay to the bulbs. I’m ok with that.


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[19963.4lsr5]

So today I was looking for a simple solution to putting my Hall effect amp meter in my rig to watch the amp output..... going from a 53mm pulley to a 50mm to speed up the Alt.

It’s a temp mounting for now but thankfully it was easy peasy. I already had a ignition switched wire under the dash waiting to be used.

The 44a is with everything on at idle in gear with the brake. (600rpm) The 19a was just engine running it dropped to 15a after it charged the battery a few min.








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[19963.4lsr5]

I forget how much I paid for this on Amazon. It was cheep and two alligator clamps for the power and one can troubleshoot any charging system.

Buy a clamp on DC amp meter and you will know how expensive they can be. I own a Fluke AC/DC clamp on amp meter. They are not cheep.


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[19963.4lsr5]

So when my rig sits 5 days my battery is down to 12.3v.

I just did the parasitic draw test and I’m at 26ma. I think it’s time to get a load tester or go to an autoparts store.









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[brillo_76]

Ah an amp meter. What's your voltage this time of year at 500 to 600 rpm with engine warm. I am at 13.6 volts at startup I hitting 14 2 volts. I am pulling it off the cigarette lighter plug at the moment making sure this used alt is working good.

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[19963.4lsr5]

Originally Posted by brillo_76

Ah an amp meter. What's your voltage this time of year at 500 to 600 rpm with engine warm. I am at 13.6 volts at startup I hitting 14 2 volts. I am pulling it off the cigarette lighter plug at the moment making sure this used alt is working good.

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I’ll let you know tomorrow morning after my 25 miles drive to work.


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[19963.4lsr5]

14.1v. At idle with headlights on.

Granted I have an aftermarket Voltage Regulator.


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[19963.4lsr5]

At home I had 14.1v at 600rpm with foot on the brake with headlights and fogs and heat on speed 2 41a showing on my amp gauge.

Same situation driving slow in the city of Lebanon I had 13.8-13.9v. Assuming a hotter Alt and VR.


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[19963.4lsr5]

So i got tired of my battery not behaving properly. My battery was 12.1 this morning sitting overnight. It never let me sit it’s just it was rated at 800cca and only produced 550cca just after buying it. But it passed their 1000a load tester test. It was purchased June of 2017.

I took it to interstate today and they tested it as borderline bad and replaced it on their prorated scale.

I got it for half price.

I tested it with my MidTronics and it tested at 770cca rated at 750cca.


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