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Old 01-17-2017, 09:48 AM   #1
C1ph3r
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High voltage after alternator conversion

I just converted my alternator to internally regulated.
Alternator is a 94 amp 12 o'clock 12SI
I have a 1970 C10 w/350

My problem. First I have a very good Blue Point digital multi meter. I only point that out to show I have a known good tool.

When I check voltage at the BATTERY, it is so high it tops out my meter. In fact, it does something I have never seen. As soon as I hook up the ground to the batter, my meter starts reading voltage.

When I check voltage where the red wire coming from the lug on alternator and meets at the wires at the old external regulator plug, i get 14.5-15 volts. Very steady. That is what I assume it should be.

Now here is how I have my wiring.

I have the brown wire from the fire wall going to pin number one on the alternator. I have pin number 2 going to the the bundle of constant 12v wires on the driver side fender.

I am accomplishing this by jumping the white wire at the alternator that goes to pin 1 to the brown wire at the old external regulator plug which goes to the fire wall. I am jumping the red wire to the blue wire at the regulator plug for the sensing.

I am still also using the same red wire on the battery lug that was there with the original alternator.

I have verified that pin one is indeed going to the brown wire at the fire wall via a continuity test. And the same with pin 2 going to 12v.

i followed this thread. http://67-72chevytrucks.com/vboard/s...d.php?t=342596
the one in the FAQ regarding this isn't correct for my truck as I don't have a light i have the AMP gauge.


Here are my jumpers and my alternator plug (Sorry for the dim photo of that). Also a pic of my amp gauge in the dash with engine running.

I am also going to be doing away with the soldered bundle on the drivers side where the battery cable and the other 12v source wires all join and making the connection with a bus bar. I just want to get this sorted first.
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Old 01-17-2017, 09:52 AM   #2
C1ph3r
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Re: High voltage after alternator conversion

basically those jumpers at the external regulator plug are doing the same thing as this plug over at classic parts. http://www.classicparts.com/1963-72-.../#.WH4dlhsrJQI
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Old 01-17-2017, 11:14 AM   #3
VetteVet
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Re: High voltage after alternator conversion

I don't follow your second sentence about the voltage reading as soon as you connect the battery ground. What voltage are you reading and where are the meter connections.
The 14.5 volts is the correct charging output for the alternator.

Your connections appear to be correct as the following diagram shows.


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Here is how I do it for a much cleaner look and it eliminates the external regulator and the wiring mess. You can still use the white and blue wires
to extend the brown and reds if you need to.

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Notice the two small wires on the diagram (black and black/white stripe.) These are the battery gauge wires and they should have a small four amp fuse in each wire to protect the gauge in the dash.

Your gauge doesn't appear to move. It should move left when the engine is off and the lights or heater fan are on or any other amperage draw. It should read just to the right of center when the engine is running and the alternator is charging. It may read farther to the right if there is a low battery or a large draw on the system.
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Old 01-17-2017, 12:09 PM   #4
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Re: High voltage after alternator conversion

That is for the reply. Yeah so when I'm standing at the front of the truck at the battery, I hook my ground lead to the battery, and before I connect the positive lead to anything, my meter starts reading vintage. It is so bizarre.

Yeah it all appears hooked up properly. I will be using that second diagram to clean up the wiring once I get some more wire to run from the alternator to my bus bar and then to the battery.

My amp gauge pic is of it running. It just moves ever so slightly when the truck is off versus when it's running. Slightly left of center where is is now and the image when running. Hope my gauge isn't bad.
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Old 01-17-2017, 12:11 PM   #5
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Re: High voltage after alternator conversion

It's just really odd how high it reads on my meter when at the battery. Almost like electromagnet interference or something.

Should I hook that little noise filter capacitor back up to the wire going to the gauge? Looking at how it was wired into the factor regulator it appears that's where it should go. I don't want noise in my radio whenever I get around to putting one in.
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Old 01-17-2017, 02:30 PM   #6
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Re: High voltage after alternator conversion

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Quote:
Originally Posted by C1ph3r View Post
It's just really odd how high it reads on my meter when at the battery. Almost like electromagnet interference or something.

You shouldn't get any reading on the volt meter when only one lead is connected. I would try a different multi-meter.

Should I hook that little noise filter capacitor back up to the wire going to the gauge? Looking at how it was wired into the factor regulator it appears that's where it should go. I don't want noise in my radio whenever I get around to putting one in.
That capacitor (filter) was meant for the external voltage regulator, to cancel out the resonance of the regulator points, which you won't have with the internal regulated alternator, so I don't think you will need it. It wouldn't go to the battery gauge wire in any case.
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Old 02-22-2017, 03:19 PM   #7
hdff
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Re: High voltage after alternator conversion

Hi vettevet, looking at your diagram on my very limited electrical knowledge (i'm trying to learn) what is the black dot I have circled #1, is that the evr?? also #2 says fusible link on the wire from the battery is a fusible link an in line fuse. I am considering a larger amp alternator and am just trying to get a total understanding of what all I need to do prior to doing it. I think I understand this pic except for the 2 questions I've ask. thanks for your knowledge and help
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Old 02-22-2017, 03:36 PM   #8
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Re: High voltage after alternator conversion

Quote:
Originally Posted by hdff View Post
Hi vettevet, looking at your diagram on my very limited electrical knowledge (i'm trying to learn) what is the black dot I have circled #1, is that the evr?? also #2 says fusible link on the wire from the battery is a fusible link an in line fuse. I am considering a larger amp alternator and am just trying to get a total understanding of what all I need to do prior to doing it. I think I understand this pic except for the 2 questions I've ask. thanks for your knowledge and help
i can tell you from just doing this, the number 1 you have circled, that is where all the constant 12v wires come together on the driver side around the inner fender. It's basically a distribution block more or less.

My understanding is a fusible link is pretty much a fuse. But it's a wire that basically melts away like a fuse would in the event of a short. SO the wire breaks instead of catching fire.
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Old 02-23-2017, 12:56 AM   #9
VetteVet
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Re: High voltage after alternator conversion

Quote:
Originally Posted by hdff View Post
Hi vettevet, looking at your diagram on my very limited electrical knowledge (i'm trying to learn) what is the black dot I have circled #1, is that the evr?? also #2 says fusible link on the wire from the battery is a fusible link an in line fuse. I am considering a larger amp alternator and am just trying to get a total understanding of what all I need to do prior to doing it. I think I understand this pic except for the 2 questions I've ask. thanks for your knowledge and help

I just noticed this new addition to the thread and your questions are easy for me but I will post a picture to help.

Your no. two circle was explained very well by C13HPR. The fusible link is a wire that burns in two if you have a short or too much load on the circuit. They are usually 30 amps for our trucks but you can get them in different amperages for the various loads you may use.

They come in short wire lengths and are four sizes smaller than the wire they fuse. they are designed to be used where current surges are present where the total current draw might exceed the rating for a glass fuse (fast blow) and they burn in two slowly so they usually last through the surge without breaking the circuit.

Your no. 1 is the factory main junction for the power wires in the engine bay including the battery, alternator, external regulator, and the cab power wire. If you have the gauge dash, the ammeter wire will also go there.

Here's a diagram.

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Here's what mine looked like when I untaped the harness.


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