Has anyone heard of an issue where the charging system on a truck keeps killing batteries? I am still having an issue where I have an 8v battery, rebuilt genny, and new voltage regulator that was installed by a local service shop that has been working on this truck since it was purchased new back in the 40's.

I can currently see 8.04 volts on the battery when out of the truck. When running, it shows 8.00 volts with a small dip, then goes back to 8 when it is revved up.

The last battery was only a few months old and Napa said it was dead and wouldn't take a charge. They gave us a brand spanking new 8 volt commercial battery that works great for about 2 months, then it's dead. When charging it up to 6v (high) I get sparks when connecting the clips. I am going + to red and - to black.....it never charges. When using a smaller, cheaper charger, the breaker (or fuse) pops and I have to unplug it to reset.

Does anyone know if it is possible that the voltage regulator or genny can destroy batteries? The water level is good on all 4 cells.....I don't know what else to do. I brought up the idea of replacing the generator with an alternator and the members of the fire department want to find out why this happens rather than replacing the parts. I understand this, but really just want to get the darn thing fixed.

Also, when parking this truck between parades, it is in an unheated storage unit with both terminals on the battery disconnected. I drove it today to parade and it was fine. As soon as I shut it down in the garage, it would not refire....DEAD.

here are some pictures of it. https://www.facebook.com/media/set/?...1084849&type=1

 

is your truck positive ground? are you disconnecting the battery cables before charging? is the charge system set up to handle 8volt, or just standard 6volt? any possibility there are parasitic draws from other systems on truck? a master disconnect switch would be a good idea. if the regulator contacts are sticking when shut down, current will flow. almost sounds like gen/reg wires are crossed up. double check these wires. by the way--nice job on resto!!

 

The truck is a positive ground. The cables are disconnected when attempting to charge the battery and right after the truck is shut off. I did not install the generator, but last year it was rebuilt and new regulator installed. The garage installed the 8v battery and the output to the battery when running is 8v....so I assume they set it up this way.

I used to have a master disconnect, but we removed it and just take the cables off ever time it is shut off, so I would guess there would not be any draw once cables are off.

Is there somewhere I can look to verify what wires should go where in relation to the coil, regulator, and gen?

Thank you for suggestions and props on the restoration....hopefully I can get this thing up to par before spring.

 

try motors or chilton books. if you installed a new wire harness, this info would be in schematics. i have a schematic sheet in my files, will dig it up and get back to you.

 

Hey, thanks a lot petey! I have been thinking about this and might just disconnect the stock wires from the voltage regulator to the generator and connect new, better quality wire between the two. I think this might help. I just found a picture of the current setup on my pc and i can see corrosion on one of the wires through the frayed insulation.

 

make sure to check all wires and connectors, if one looks bad, the rest are more than likely in a similar condition. don't forget to inspect the voltage resistor--should be under dash-somewhere. i suspect the truck is using/producing too much voltage when running, either drawing life out of battery or cooking it. so---now for the big question. you have put so much effort into this unit to get where you are---why did you not replace the wire harness and make it----perfect?

 

I guess I should probably take this winter and check all wires. The reason the harness has not been replaced was because this truck belongs to the fire department and they don't like spending their cash on upgrades to the truck. I would love to replace the wire harness in the truck....how big of a job can I expect that to be?

 

I'm about to rewire my '46 so I'll let you know... I have the typical 65 year old mess under the dash.
My cowl harness was $219.00 at macauto.com I don't know if the harnesses are the same or not between a '41 and a '46 but it's real purty and will make life much easier.

 

this is not a hard job, but to do it right takes time. once you have harness laid out so it fits proper, it's really all about clean connections and good looks. i had harness laid out in my 42 in a couple hours. however---i'm ****, and it took me a couple more days to hook everything up to my satisfaction. i replaced EVERYTHING on truck, including headlight sockets, parklite sockets, guages, etc. 25 years later, all still works just fine. do it once--do it right--it will outlast you.

 

just looking for an update. did you get a chance to find problem?