what does voltage regulator do?

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Otateral

Otateral

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I posted a while back due to overcharging issues. I got it mostly resolved, but the volts were still a little higher than I would have liked.

Today, I installed a new voltage regulator since it's the one thing I haven't tried. Now, the voltage on the field wire seems to fluctuate. Meaning, I'll show 7v, 12v, 5v, 15v intermittently.

I can't remember what it should specifically show, but I will assume this isn't right.

Im now getting 15.1-15.8v charging at idle.



This has the madd bypass. Terminals cleaned as good as I could get them. Minor voltage loss to the ign side of the regulator.
 
Which alternator are you running? Square back or single wire? If square back ground the other terminal to the block.
 
Duh, it regulates the voltage... sorry i couldn't resist lol. I'm interested to see what and how it actually works.
 
Forgot to mention that. ive got a 2 wire alt. I do have a ground cable connecting the alternator bracket to the voltage regulator's mounting stud.
 
Otateral said:
. Minor voltage loss to the ign side of the regulator.
Click to expand...

What do you call minor?

ANY voltage drop in the ignition harness ramps up the battery voltage, because the regulator SENSES charging voltage at the regulator "I" (IGN) terminal. So if that voltage is LOW with key on/ engine off, the difference between that point and the battery gets added to the regulator set point

This means that if a (warm) regulator is properly operating at about 14v (13.8--14.2) and you have say, .8V drop between the battery post and the IGN run wire, you'll end up with 14.2 + .8 will be 15V at the battery terminals.

There are several reasons for too high voltage-----------

1--Improper regulator set point, usually found in older mechanical regulators, but sometimes in solid state ones as well

2--The fore-mentioned harness drop between battery and "ignition run."

3--The last is ground. You must have the regulator "same as" battery neg. Clean the firewall and regulator and ground with star washers. It does not hurt to use a no10 or larger ground wire from the regulator mount screw to the neg. battery post.

Many of my posts on this site deal with these very issues.
 
Last time I checked, I was at .4v loss in the ignition circuit. Mostly what concerns me is why the voltage at the field wire fluctuates normally by several volts.
 
Voltage at the field wire WILL fluctuate, as it's being modulated by the regulator. I'm not sure any shop manual even has a spec for that. Only thing specified is current draw of the field when supplied with full 12V
 
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