Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

Have 49 Ford with original 8BA engine, generator, starter etc. Car is pretty much all original. Generator was just cleaned, new bearing and carbon brushes installed. Problem, voltage with engine running at driving speed I get a voltage reading at battery posts of 6.64 to 6.67 volts. Measured generator output with volt meter to the armature and ground and get a consistent 7.34 volts.
the battery is a NAPA 6 volt CCA at 32degs of 1200,
the regulator is a FILKO VRF-312HD looks like new inside.

battery load test checks out good.

after starting car several times and running the engine at various speeds, the voltage at battery terminals is only at 6.64 to 6.67 volts.

Question: why the low voltage at battery, is problem such as wire gauge size for generator connection to regulator and battery connection to regulator or where else do I look at? Or is this a normal voltage at battery terminal after starting engine and battery has plenty of amps left in it?

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

What happens when you turn the headlights on?? The regulator is adjustable.
Paul in CT

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

Try the voltage at the armature and battery terminal at the regulator

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

I would run a 10 Ga wire, from the voltage regulator to the battery terminal bolt and see if the the voltage rises. If it does rise, it's the wire in the loom is bad.

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

It's doing something if your voltage is above 6.1-volts.

A person has to have the proper equipment to thoroughly check and adjust the old 3 pole regulators. The procedure for checking these systems is in the manufacturer's overhaul manual. An adjustable volt/amp meter with the resistance dial is needed to perform the tests. Putting a volt meter across the battery terminals only tells a person so much. It works well enough for alternator systems with electronic voltage controllers.

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

I am new to website so hope this is the way to respond. Thank you all for the fast responses.

With lights on engine at normal drive speed say 45mph
volt meter testing:

1. regulator Batt position to battery terminal avg 6.8 volts
2. ARM to regulator Batt position volt .34
3. Battery terminals + - voltage 6.37
4. ARM to Gnd voltage 7.48

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

Clean the cutout contacts in the regulator--- or try another regulator

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

Yep like the others said you are droppping a volt or so. Thats too much voltage drop should be 7.2- 7.3 at gen and same at battery .......too much voltage drop in harness etc.....

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

You have .7 volt drop. Start at the arm terminal on the gen, then to the bat and arm terminals on the regulator, terminals under the dash, the solenoid and the battery terminals by cleaning each terminal with fine sand paper or file until each terminal is shining and clean. Then reassemble each terminal and make sure it is tight. Clean and tight.
The connect the positive lead of your voltmeter to the arm terminal on the generator and the negative lead to the battery negative terminal, run engine at 2000 rpm and switch the voltmeter to its lowest DC scale. This will give you the voltage drop between the gen and bat and a reading of .1 - .2 would be acceptable. Running this test before any cleaning should show .7 volts. With the positive of the voltmeter connected to the arm terminal on the gen, connect the negative of the voltmeter to the arm terminal on the regulator again run the engine at 2000 rpm. Reading should be not over .1 volt and then move the negative lead of the voltmeter to the bat terminal of the reg and again with the engine at 2000 rpm, the voltage drop on the voltmeter might be .1 and if it jumps to say .5, then as has been suggested clean the cutout points in the reg and then retest. This is an application of Ohm’s Law (V = IR). The resistance is constant and the current (I) increases when the engine rpm goes to 2000 rpm, thus increasing the voltage drop. I have experienced this same problem and the above is the solution I used. Give it a try.

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

Thank you for the test method of voltage drop. I will work on doing that.

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

The contacts in the regulator operate by intermittent (buzzing) contact. Efforts to change the settings without the necessary equipment almost always results in replacement of the regulator. Be sure that the engine is grounded to the chassis with a separate cable to provide a good ground to the generator. Also check to see that the regulator is properly grounded to the firewall. A one time regulators had a grounding lug, then using a brass insert in one of the "feet" of the unit came into style. In either case, be sure the grounding place on the firewall is free of paint and grease.

Re: Generator output voltage 7.3v drops to 6.6V at battery this normal or not
 

It is quite possible it is the regulator. Brand new ones can be out of adjustment.
Have it adjusted by a pro to be sure.