Battery not charging

[WQ59BJR]

Basic data:
1940 Ford COE
1946-48 "59AB" V8 flathead engine
all original except for wiring completely redone and electric fuel pump and fuel regulator added,
6 volt, positive ground

Ran truck a few times and noticed it started cranking slower and slower with every start. Had trouble starting it once and ran battery down until it wouldn't crank. Recharged battery and tested across terminals and got about 5.7 volts. Got truck started and while running, tested battery across terminals and got about 5.7 volts no matter how fast engine was reved.

Started with generator: Tried to "motorize" it by taking it off the truck, jumping the field and armature terminals together, connecting negative battery terminal to jumped generator terminals and positive battery terminal to ground on the generator case. Generator barely moved. Opened it up and commutator coated in greasy film with all slots filled. Cleaned commutator, brushes (2), slots brushes ride in and put in new brush springs. Re-did "motorize" test and it spun nicely locked in a vise.

Reinstalled it in the truck without any wires connected to it just to spin it. Jumped the field and armeture terminals and connected a volt meter. Red lead to ground on generator case, black lead to jumped terminals. Started truck. Volts climbed to approx 6.25 then immediately killed engine. According to what I've read these tests show that the generator is mechanically OK and producing electricity.

Hooked everything back up, tested battery (5.7 volts) then started truck with meter on battery. Reved engine pretty high for a good 15-20 seconds but never got above 5.7 volts at battery. Figure its got to be the voltage regulator (of which I know squat). The one on the truck is a replacement. All I can make out on the faded cover is "Filko, Crown Jewels of Ignition". It has three connection points, ARM, FIELD and Batt.

After everything I've read, here is MY simplified understanding of the voltage regulator: The Batt (cut out) terminal says when and how long to run off the battery or when and how long to run off the generator/charge the battery. The ARM (voltage regulator) controls how many volts come from the generator and the FIELD (current regulator) controls how many amps come from the generator.

I connected a volt meter to the ARM terminal on the generator and ground to test the cut out as per a shop manual. Increased engine speed until I got 6.25+ volts then slowly decreased engine speed. Cut out points were supposed to open when voltage dropped to 4.2-4.8 volts but voltage never dropped below 5.7 volts? Could it be that engine is just idling too fast?

I don't have an amp meter so I can't test, according to the shop manual, the current regulator.

Phew!, OK, so here's my question: If I connect a volt meter to the Batt terminal and ground, then start and rev the engine and adjust the voltage regulator (at the ARM terminal) until I get 7.1-7.4 volts (got that from the shop manual) AND lower the idle speed, will I have solved my charging problem?

Yeah, I know, I can just get another voltage regulator but I'd like to keep what's there and I have no idea (amp size) which one to get.

[rotorwrench]

When you adjust this stuff, you need to have the proper test equipment. It also helps to just perform normal testing by the book so having a good book also helps. Motoring a generator is not a very good test. I would start by properly flashing the field. This sets up the residual magnetism in the pole shoes with the proper polarity. Disconnect field wire from the regulator and touch it to the battery terminal on the regulator momentarily then reconnect the terminal. Now it has positive ground polarity for a normal 6-volt system and is ready to generate. It's the residual magnetism in the pole shoes that starts a weak generated volt/amp to close the cut out and bring the generator on line after engine start up. Once the cut out closes, the system voltage should rise above the battery voltage. If it doesn't then there is either a problem with the generator or the regulator. You have to test a voltage regulator with a known good battery and generator. Adjusting a voltage regulator is tricky and should be done by the book or by someone who knows how to do it. I learned this stuff by watching a trained tech do the job correctly. I didn't learn on my own. Things can go south quickly if not done correctly.

[drolston]

Step one, be sure you have a good battery.

When you say you recharged the battery, I assume you mean with an external battery charger, not by running the engine. If so, a battery that reads 5.7 volts after charging is not a good battery. It should read well over 6 volts.

Try disconnecting the battery from the truck and give it a full charge. Look for voltage about 6.5 volts. Turn off all the ignition, all lights and accessories. Look for no sparks when hooking it back to the truck. If it sparks, find what is drawing current, and fix it. Start with the field wire of the generator, in case the regulator is malfunctioning in that switch.

If no spark, turn the headlights on; the battery voltage should drop by no more than a few tenths if the battery is good.

Step 2, be sure you have good ground, battery to frame and engine.

Cables not too small? Any sign of corrosion on any battery cable is cause for replacement. They can get corroded and degraded inside the insulation.

[Paul Bennett]

6.3v = Good battery
7.1v = Adequate voltage to charge or maintain battery while running.
Voltage over 7.4 will boil the water out of the battery-avoid

Arm = armature winding (rotates) which outputs recharge juice
Field= winding which produces magnetism to generate juice in the armature
Voltage Regulator= device which keeps generator below 7.1-7.3 volts
by depriving field voltage intermittently.

To generate adequately, an initial residual magnetism is required - briefly apply voltage to 'Field' with regulator disconnected. Briefly=very quick

[WQ59BJR]

I was trying to keep my post brief so I left out that after the generator was reinstalled I turned the ignition switch on and quickly tapped the Batt to the Field terminal on the voltage regulator to polarize it. The reason I only charged the battery off the truck to 5.7 volts was so I would have enough to start it and then see it start charging right away, which it didn't. Also, all the wires/connectors are new and all contact surfaces were polished shiny clean.

[rotorwrench]

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The generator field coils have to be isolated from the voltage regulator F terminal. The wire has to be disconnected or it can damage the regulator. You can also disconnect the field wire from the generator and use a jumper wire from the battery negative terminal to the field terminal. Either way will turn the field coil into a DC magnetizer for the pole shoes.

I used to magnetize parts to perform magnaflux inspections using a DC coil. I then had to demagnetize them with a large AC coil.

A voltage regulator can have a burned pole winding or crusty regulator points. The cut out or current limiter pole can suffer similar problems. There could also be a shorted armature winding or open circuit winding. It takes a growler to detect stuff like that.

[old Tom]

Originally Posted by WQ59BJR

Basic data:
1940 Ford COE
1946-48 "59AB" V8 flathead engine
all original except for wiring completely redone and electric fuel pump and fuel regulator added,
6 volt, positive ground

Ran truck a few times and noticed it started cranking slower and slower with every start. Had trouble starting it once and ran battery down until it wouldn't crank. Recharged battery and tested across terminals and got about 5.7 volts. Got truck started and while running, tested battery across terminals and got about 5.7 volts no matter how fast engine was reved.

Started with generator: Tried to "motorize" it by taking it off the truck, jumping the field and armature terminals together, connecting negative battery terminal to jumped generator terminals and positive battery terminal to ground on the generator case. Generator barely moved. Opened it up and commutator coated in greasy film with all slots filled. Cleaned commutator, brushes (2), slots brushes ride in and put in new brush springs. Re-did "motorize" test and it spun nicely locked in a vise.

Reinstalled it in the truck without any wires connected to it just to spin it. Jumped the field and armeture terminals and connected a volt meter. Red lead to ground on generator case, black lead to jumped terminals. Started truck. Volts climbed to approx 6.25 then immediately killed engine. According to what I've read these tests show that the generator is mechanically OK and producing electricity.

Hooked everything back up, tested battery (5.7 volts) then started truck with meter on battery. Reved engine pretty high for a good 15-20 seconds but never got above 5.7 volts at battery. Figure its got to be the voltage regulator (of which I know squat). The one on the truck is a replacement. All I can make out on the faded cover is "Filko, Crown Jewels of Ignition". It has three connection points, ARM, FIELD and Batt.

After everything I've read, here is MY simplified understanding of the voltage regulator: The Batt (cut out) terminal says when and how long to run off the battery or when and how long to run off the generator/charge the battery. The ARM (voltage regulator) controls how many volts come from the generator and the FIELD (current regulator) controls how many amps come from the generator.

I connected a volt meter to the ARM terminal on the generator and ground to test the cut out as per a shop manual. Increased engine speed until I got 6.25+ volts then slowly decreased engine speed. Cut out points were supposed to open when voltage dropped to 4.2-4.8 volts but voltage never dropped below 5.7 volts? Could it be that engine is just idling too fast?

I don't have an amp meter so I can't test, according to the shop manual, the current regulator.

Phew!, OK, so here's my question: If I connect a volt meter to the Batt terminal and ground, then start and rev the engine and adjust the voltage regulator (at the ARM terminal) until I get 7.1-7.4 volts (got that from the shop manual) AND lower the idle speed, will I have solved my charging problem?

Yeah, I know, I can just get another voltage regulator but I'd like to keep what's there and I have no idea (amp size) which one to get.

Here is a quick way to test a Ford Gen & VR You might have already done this. Use a jumper From A to F on gen. If it charges it is a bad VR. If no charge quickly short A terminal to ground if it sparks generator is OK but VR bad. If no sparking generator is bad. All this done with motor running and generator turning.