How to troubleshoot 12volt not charging battery?

[GeniusAndHisAssistant]

We made it on the dirt roads late last night after 2 years in the shop!! Hooray! The IIA lives after 30 years in the barn!

Still lots of small issues to tackle though. First project is that the alternator is not charging the battery. Can anyone point out on the forum a link to electrically sorting this out with a meter? Which to look at first and such? A bullet list from anyone would be fine too. We just are not sure the most efficient way to go about it and would love some guidance to shave off many hours of stumbling through it - like we did rewiring the whole aft end of the truck.... it took more time than seemed it should?

As always thank you in advance for your time.... we could NEVER have made it this far without all of the wonderful help.

Rove on!

e & j

[SafeAirOne]

Do you have an alternator or generator? If it's an alternator, is it internally-regulated, or do you still use the external regulator (like the one in the picture), attached to your bulkhead:?



The easiest way to check for alternator output is to simply place the red lead of a voltmeter (set to the 20v scale) on the positive terminal of the battery and the black lead on a GOOD grounding point and check the meter for 13 or more volts while revving the engine UNLESS you have an external voltage regulator--In that case, put the red lead on the the terminal of the voltage regulator where the fat wire from the alternator/generator connects (still find a good ground for the black lead) and look for more than 13v.

If you have at least 13 volts at either one of those locations, there's some other problem (like a bad connection or battery or external voltage regulator, etc).

If you have LESS than that voltage, your alternator/generator isn't putting out voltage to the battery and the next step(s) would be to figure out why.

[SafeAirOne]

Oh, and congratulations!

[GeniusAndHisAssistant]

Mark, thank you for your reply. We have a regulator and generator. The regulator is exactly like the one in your photo.

I am trying to sort out what you said and test the regulator - but now I may have reversed the "A" and AI" wires. To help me trace those two wires do you know what the "A" in "A" and "AI" stands for?

I found some text to trouble shoot the hardware but the wiring and all is so old it is a challenge! - thanks for your help - it may provide some clues.

j

[SafeAirOne]

Looking at the schematic above (and presuming you have a NEGATIVE GROUND electrical system), the huge wire from the "D" terminal on the dynamo (generator.--#43 in the diagram) should go to the "D" terminal on the external voltage regulator (#29 on the diagram). When you rev the engine, you should see at least 13 volts between this wire and a good ground if the generator is putting out voltage.

If that's OK, you should check for at least 13 volts (engine revving) between the "A" terminal on the voltage regulator and a good ground. Same with the "A1" terminal and a good ground.

If you had 13+ volts on the "D" terminal while revving earlier, but not on the "A" or "A1" terminals now, something may be wrong with the external voltage regulator.

If you DIDN'T have 13+ volts on the "D" terminal earlier then check that you have battery voltage between the "F" terminal and a ground. The dynamo (generator) needs electricity coming down this wire in order to create electricity.

Also make sure there is a good electrical connection between terminal "E" on the regulator and ground.

[GeniusAndHisAssistant]

We'll do the tests you mention. Thank you for attaching the photo too.... we can read the wire colors on that one unlike the copy we have. Sweet!

j & e

[aleutian06]

Mark's photo is an RB106 VR. I think the A stand for Ammeter. The RB340, a later VR, has B instead of A as a marking. Meaning battery of course.
I had and an RB310, but switched to an RB340. The RB106 may be a two spool vice three spool on an RB310/340. Maybe had to do with the grounding. The RB340/Lucas C40 Dynamo was used on several different American tractors to include the 60-70s Fords. Hence, you can find it at a slightly lower price if you shop around.

Keith

Keith