Alternator and voltage regulator question

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sparkie573

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Any idea why a new 1 wire alternator would crap out the voltage regulator after only a month? I got one in from summit and installed it. I haven't been driving it that much. I was out driving and tinkering with tuning in my carburetor and it started charging 18-20 volts all of a sudden. So, I limped it home and called summit. The guy said he didn't have a problem exchanging it. But my question is what would possibly make a voltage regulator go out and what all should I check??
 
Hard to say. "I don't like one wire alternators."

One reason MAY be your wiring. Did you install this on a car with a factory harness, using the factory bulkhead connector and ammeter "un" modified?
 
Is there any chance that any of the system connections are erratic or dirty? The battery has to be solidly connected to the alternator at all times to act as what is called a 'ballast'.... to provide a stabilizing load. Any erratic connections can allow the alternator voltage output to spike up to a very high voltage, and can damage the VR or the alternator's diodes. Hence the questions above about your wiring.

Del, actually it is very easy to say "I don't like one wire alternators" ! LOL
 
That is very possible. I haven't gotten a chance to check everything out yet. I think it's something of what your talking about. At operating temp at idle it's right at or under 15 on my gauge. When I drive it, it will be fine for a bit and then get erattic . It seems to jump up when you get on it, but not all the time. Think it's a hot side connection or grounding issue?? I'm going to start checking everything and I'll post what I find... As far as the car,, battery is in the trunk, alternator is on the driver side, full msd ignition, and bulkhead is modified, also ammeter is bypassed. Any opinion or help is great.
Thanks
 
The "jump up when you get on it but not all the time" might indicate an erratic connection that is occuring due to the motor torquing/jumping around or just hard vibration. It is hard to say exactly where it is.

I would just start with the easiest, the ground side, and make sure all metal surfaces are clean and bright; and I would put No-Ox (or better yet, Cramolin) on the connections. Do you have more than one ground cable/strap from engine to chassis? Make sure you check the battery connection to chassis at the back too. Then move onto the hot side wiring and components.

I would connect a needle indicator voltmeter on the battery + and - by using 2 long test leads, and monitor that versus the VM in the car; you might see it jump on the car's VM and not on the test VM at the battery. Moving the test voltmeter's +connection point further and further towards the alternator might show the problem point.
 
How do you have the charging line routed? ESPECIALLY with a "one wire" it's imperative that the line be oversized and good connections. Part of the reasons for this, is that the VR "sensing" is right at the alternator!!! This means that if the charging wire is a bit small, you'll have voltage drop between there and the battery. If your main loads are connected down closer to the battery, it may not run at proper charging voltage, IE the V drop on the charging line
 
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