Voltmeter with a generator
 

I am just finishing a project. It has a brand new generator and regulator (polarized). I just installed an under dash voltmeter. Starting the vehicle up and idling it has about 12.5 volts.About the same with more RPM's.... I am used to (other projects) that have a bigger output "alternators" usually showing about 14 volts. Is it normal for a generator system to only put out just over 12 volts to a voltmeter guage?

Re: Voltmeter with a generator
 

It depends on how sensitive the new under dash meter is.
With a hand-held volt meter measure the battery voltage when the engine isn't running.
Then measure it with the engine at about 1200 rpm, the voltage should be maybe 1.5 volts higher.

Re: Voltmeter with a generator
 

Do you have a FORD SHOP MANUAL for the application?

Do you know the GEN AMP output rating? Is the mechanical REGULATOR rating matched to the GEN?

Is the VOLT REG adjustable? A GEN will not cut-in until about 1000-1200 RPM. There is a full DIAGNOSTIC ROUTINE in the manual and how to adjust the REG, if is adjustable.

Re: Voltmeter with a generator
 

When checking a generator, make sure the generator is up to "operating" temperature. It can make a difference.

Re: Voltmeter with a generator
 

At fast idle (with a generator) it should be between 13.5 and 14.3 volts. A little over wouldn't hurt.

Re: Voltmeter with a generator
 

Checked it out yesterday and with the engine warm at about 1200 to 1500 RPM, I have just 12 volts at the voltmeter guage.

Re: Voltmeter with a generator
 

If you are comfortable that your voltage readings are correct then you have a charging problem. A 12-volt regulator has to have a voltage output higher than the battery voltage in order for the battery to start accepting a good charge rate. Older voltage regulators can be adjusted but it takes some good test equipment to set voltage and check the current limiter. A shop that specializes in auto electric components should have the equipment to do that.

Modern replacement regulators leave a lot to be desired in quality.

All a voltage meter will ever tell you is that the system is generating a specific voltage. An ammeter indicates charge, discharge, and approximate amount of current draw from the load.

Re: Voltmeter with a generator
 

What procedure did you use to polarize the generator?

I take the Field wire loose from the regulator and quickly brush the end of it across the Battery terminal of the regulator, then re-connect the Field wire.
So you're Not applying battery power to the Field terminal of the Regulator, only to the Field wire that leads to the Generator.

Re: Voltmeter with a generator
 

Did exactly as above to polarize the regulator. I know that because before that the factory GEN light stayed on when I started it in the shop and is OFF now after I polarized it.

Re: Voltmeter with a generator
 

Having the Gen light working is a good sign but if additional voltage isn't showing up at the battery terminals with the engine running there is a problem.

I'd start checking things by disconnecting a battery cable and removing the cover of the voltage regulator to see if the relay/switch contacts need cleaning. Emery paper or a small fine 'points' file may fix it.
.

Re: Voltmeter with a generator
 

The generator light function is switched inside the generator control unit or voltage regulator (VR). When the generator starts generating current there is a switch function in the current limiter pole circuit that opens the ground path for the generator light and the light goes out so at least it's showing some function. If voltage is low then the voltage regulator pole is not properly adjusted to a high enough voltage for operation.

Make sure you have good connections with the generator to VR and battery to buss/frame. Grounding of the generator to the frame and in most cases, the voltage regulator to the body have to be good. When there is no ground wire between the generator and regulator then this ground has to come from other sources. This also includes grounds from the engine/frame to the body. If all are good then either try a different regulator or find someone who can properly adjust it.

Re: Voltmeter with a generator
 

Repeat of POST #3 -