Continued Charging system troubles


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Post Mon Sep 24, 2018 8:09 am

Continued Charging system troubles

Hello, I have been fighting some issues with my ignition and charging systems on and off and could really use some help.

It is a 1964 C900 with a 4-152.

It began with my battery constantly being dead after driving. I checked the alternator output and found it was only 12.15 or so, and didnt compensate for load at all. As of now I have replaced the alternator, battery, voltage regulator, battery cables, starter solenoid, and ignition switch. Currently, the alternator is only putting out about 12.17 V (when I replaced everything, it would put out about 12.5 compensating for load.)

Is it possible my new voltage regulator has gone bad, I didn't replace the capacitor, but wasn't sure if it could cause this issue. Is there a good way to check the voltage regulator?

What seems like a significant issue to me, is that my ignition switch often will not start the truck. The ammeter dips to zero when I attempt to start it, but if I jump the starter with a screw driver, it starts without issue. Is there possibly a short in the ignition circuit which is draining the battery?

Would it be simpler to install a one wire alternator instead of using an external voltage regulator?

Thanks
1964 International C900 Pickup
1987 Subaru RX-Turbo
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Post Mon Sep 24, 2018 9:48 am

Re: Continued Charging system troubles

Sound more like you have no grounding between the engine and body. Run the neg terminal from the battery to the block or starter mounting bolt. Run grounding straps between the engine and the body, chassie and voltage regulator. This truck should have a DN-10 remote regulated alternator.

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Post Mon Sep 24, 2018 10:14 am

Re: Continued Charging system troubles

I like CBs idea. Most problems have simple solutions, so I, too, would suggest checking out your grounds before doing anything more invasive.
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Post Mon Sep 24, 2018 10:21 am

Re: Continued Charging system troubles

Awdsome001 wrote:What seems like a significant issue to me, is that my ignition switch often will not start the truck. The ammeter dips to zero when I attempt to start it, but if I jump the starter with a screw driver, it starts without issue. Thanks

with no load the ammeter SHOULD read zero, when a load is placed on it should go to the - side (discharge) and when the engine is running it should go toward + side (charging) for awhile slowing decreasing as the battery charges, ending up at zero again.
If you ammeter show other than that, you have wiring problems.
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Post Mon Sep 24, 2018 4:58 pm

Re: Continued Charging system troubles

cornbinder89 wrote:Sound more like you have no grounding between the engine and body. Run the neg terminal from the battery to the block or starter mounting bolt. Run grounding straps between the engine and the body, chassie and voltage regulator. This truck should have a DN-10 remote regulated alternator.


I will give that a try! I recently replaced the battery cables, the negative is run to the alternator bracket. I'm currently reading only battery voltage on my multimeter when it's running, even if I disconnect the voltage regulator (which if I remember correctly should cause the alternator to produce full output at about 17V.)

I did disconnect all the wiring and clean up all of the terminals in the engine bay relating to the alternator, battery, and starter.


cornbinder89 wrote:with no load the ammeter SHOULD read zero, when a load is placed on it should go to the - side (discharge) and when the engine is running it should go toward + side (charging) for awhile slowing decreasing as the battery charges, ending up at zero again.
If you ammeter show other than that, you have wiring problems.


My mistake, that's exactly what I meant... The ammeter dips to the negative side when I try to start it but the truck doesn't start to turn over. I though it might indicate a fault in the ignition switch circuit since it will still start when the starter terminals are jumped. I suppose it could just be increased resistance though.
1964 International C900 Pickup
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Post Mon Sep 24, 2018 5:05 pm

Re: Continued Charging system troubles

Disconnecting the regulator will shut down the alternator, not full field it. That has to be done with an external connection.
A 12 volt alternator can produce enough voltage to fry the diodes (over 120 volts) if turned fast enough with a full field, and no load.

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Post Mon Sep 24, 2018 5:18 pm

Re: Continued Charging system troubles

A lead-acid battery has 2.2 volts per cell.
2.2 (volts) x 6 (cells) = 13.2 volts.
Your Alternator / Voltage Regulator combination need to put out more than 13.2 VDC in order to charge the battery.
Adjust the VR.
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Post Mon Sep 24, 2018 5:23 pm

Re: Continued Charging system troubles

Right now it is not even attempting to charge, so until we get it above static voltage, it is unlikely to be regulator set point, much more likely to be a fault in the wiring or the reg itself. Mechanical regs don't "loose" their adjustment, some have gone 70 years without failure.
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Post Mon Sep 24, 2018 7:37 pm

Re: Continued Charging system troubles

Ahhh, understood. I don't know where I got the idea that unplugging the VR would get me unrestricted output.

I will add grounding straps tonight and see if any improvements are made. Currently the VR on the car is Standard Motor Products VR103T and the alternator is a remanufactured Remy 20169.
1964 International C900 Pickup
1987 Subaru RX-Turbo
2017 Subaru WRX
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Post Tue Sep 25, 2018 12:07 am

Re: Continued Charging system troubles

Well, I added the grounding straps and no change in the status. Still showing 11.97 (battery voltage). I did however find that the negative battery strap was covered with build up where it met the alternator bracket. I cleaned and reattached, will have to follow up with it tomorrow as I just removed the instrument panel to check the wiring to the ignition and ammeter.
1964 International C900 Pickup
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