I had a similar issue but with a new battery in my 6V 2 years ago. I was shocked (no pun intended) that the truck was fine going to Home Depot during the day with no lights on, no radio in the truck, nothing drawing a charge. All new thick cables, etc. Dead as a door nail when I tried to leave.

Voltage regulator was wicked hot. Looked "newer" but had failed spectacularly. Got a new one and an all-new wiring harness for it, hooked everything up exactly the way it was and all worked well. Except my gauge now stays dead center (as does yours) when the truck is running, so the only thing telling me it's working well is that the truck has been fine since that time, lol. I never run the headlights, but all other lights and the heater works just fine and never depletes my battery.

long way of asking....is the voltage regulator ok?

 

I learned a lot about generators and how important they are years ago. I was about 1 year out of college and had a beautiful 55 Chevy. A fraternity brother, also graduated, and I were going back to the college for a weekend of debauchery. I picked him up in my 55 on a Friday evening.. From his place it was about a 2 hour drive.

Part way there the Gen light came on. I thought as long as I don't turn the car off it will be fine and I'll look into it Saturday morning.

Well we are on Interstate 80 heading west. It is getting dark. I turn on the lights and the car almost shuts off. So I keep just the parking lights on so I can be seen from the rear. Then it starts to drizzle. I turn on the electric wipers and the car almost shuts down. I knew them that we were in trouble. I didn't want to park it and walk to a phone booth. I didn't want to go out the next morning and see my 55 stripped and up on blocks. To stay between the lines we had to stick our heads out the window to see. Then a trucker comes up behind us and puts his 4 ways on. His headlights lit up the road in front of us. We made it to our exit and crept the next 7 miles to the fraternity house.

We walk in the house. The guys said "what's wrong with you?" We were soaked, still shaking, and our hair was swept straight back! The next morning I went to a local junk yard and exchanged my genny for a good one. Wow! Scary night.

And lesson learned!

 

Look at it this way Abe. You got a great story to tell.

 

Cool story…our kids and grandkids will (hopefully) never experience this.

In the late 60s I was playing a show in eastern PA, maybe 1 1/2 hour drive. I had an old Chevy van, the kind with the engine between the front seats, 4 of us rode in the van with the gear, the other 2 followed in a car. On the way home from the gig the battery light came on, broken fan belt, missing completely. We went a few more miles hoping for a gas station but the temp light came on so I pulled over. The guys in the car found a station not too far away and bought a fan belt. All I had was a pair of pliers but I managed to get the bolt on the alternator loose, but tightening it down, the bold snapped off. The belt seemed tight enough to hold so we drove home, the light came on again maybe 5 miles from home. Stopped after the temp light came on, waited 1/2 hour or so and finished the drive. We should’ve been home by maybe midnight, when we got home the sun was coming up.

Leon Russell had a song at the time called “Manhattan serenade”. The opening line was “sitting on a highway in a broken van”.

 

Back to the original question…

How can I better monitor the generator and battery condition?

Thx for the help troubleshooting this issue, but I’d like to not be sitting on the highway in a broken truck.

 

Does the stock "Battery" gauge fail at some point and just set the needle right in the middle when the truck is on? I tested mine the other day by turning on the lights and it didn't budge. I'm hoping when my voltage regulator cooked itself, it didn't nerf the gauge as well.

Can you wire a separate ammeter along with the stock one to monitor it?

 

It's one of the reasons the auto makers have gone to volt meters instead of amp meters. People can understand them better, they're safer by not having full vehicle current running through the gauge, and is still a good indication of the charging system working. I know when it's time to clean the battery cables when the voltage shows lower than the normal 14v while driving.

 

I replaced the gauge last year with a NOS. That doesn’t mean it’s good. It does move some, but just a tiny bit. Perhaps the second gauge is a good idea. I’ve been looking for a voltage gauge but I haven’t found any for 6v systems.

 

Makes sense. Unfortunately I can’t locate a 6v gauge.

 

The beauty of the stock gauge is that it is not "in" the circuit, so failures in the system don't affect it directly. They are really pretty rugged, but do fail. I'm not sure if the 48-50 unit is the same as the 51-52, but the later style was used well into the 60's in parcel trucks so there seems to be a decent supply of OEM NOS units.

I would never put a "shunt type" ammeter in any vehicle, they have full current flowing thru them and that is what can lead to smoke and fire.

 

I suggested it as a temporary solution only. I know the ammeters are dangerous gauges. But for diagnosis, it may be necessary for a very brief period.

 

Yes, the current loop style gauge is the only way to go. I won’t install a shunt type gauge, just a bad idea all around. In IT world we’d call that a SPOF, single point of failure.

 

I’m shocked…I know, bad pun…but all the universal ammeters I see are shunt type. I may need to rethink this statement.

 

can you find a 6v tractor gauge? They could work for diagnostics.

 

yes, I’ve even looked on some tractor forums, they have the same problem. I may have to get more creative and install square a panel type gauge I have.