Batteries for Dodge M37
 

Hello,
I am in the market to purchase a couple of new batteries for my M37. It is 24 V and am using a couple of older car batteries that should be replaced. The vehicle has a generator so the batteries do not charge and I have to recharge them after I use the truck seperately I am thinking of replacing them with Marine or RV deep cycle batteries. Any suggestions? I want to keep the truck original so don't want to change the generator to an alternator.
thanks and Merry Christmas and Happy New Year! Ewen

You can go to the military 60 amp alternator (2920-00-909-2483) and still remain original. It was an approved modification to use on almost all of the M-series back in the 70s in Cdn service, and even the British ferret too. The alternator will drop into the same brackets and use the same pulley as the existing generator. You have to remove the regulator and wiring and replace it with two simple wires, one from the battery junction at the starter and one from the ignition switch..

batteries
 

Battery Direct has one that will fit your tray and hold downs , it is almost a perfect replacement for the 2HN , but first you need to address your main problem , a system that is not charging, I'm helping a friend with his M-152 , we are replacing his entire wiring system and just in time , a fire looking for a place to happen, the new harness is not cheap but fixes a mountain of future problems ,I have a second friend with a M-37 that has already had problems, I told him to get a complete harness and that I would help him, he purchased only one section of the harness and wanted me to replace that , I told him that in no way would I touch the vehicle unless he acquired the entire harness , other wise after his truck burns to the ground and he thinks I've done something wrong , these vehicles do not have fuse boxes that will blow they just burn, I've installed new harness sets on every vehicle that I've restored and I know your's also needs this , your problem can be anything from the gen or reg to rotten wiring and bad grounds , fix your first problem first,

Yo are so very right Frank.

The mil-spec prestolite wire on the M-series vehicles is some of the best wire that money can buy. But I recall back in the 80s that the 30 year old wiring was starting to short, especially at the connectors on the front fenders. The metal shells would actually get energized through a break in the insulation and cause the circuit breakers to start popping.

I re-did the M37 at the Shilo museum last year for the same reason. After 50 years, the wiring was really getting bad. It started out with a simple gauge replacement to remove the radium gauges with non-luminescent copies. But once I was under the dash, it was inevitable.

I was able to do it by ordering just the main under dash harness from John Bizal at midwest military. He has some NOS surplus ones for under $200. The rubber was still fresh and pliable. I added the extra wires needed for the Cdn Dodge....things like the convoy light and the turn signals. Since the DND still uses that same wire and the connectors, I was able to make up the harnesses for the front corners and the harness to the rear including the trailer receptacle. But it was a lot of work, soldering and crimping all those connectors. If your time is worth anything, you may just want to buy the whole harness. If you have to buy the wire and connectors, it will end up just about coming out to the same amount anyway. Just those little rubber insulators are 50¢ each these days.

I would not recommend using the modern day plastic coated wire. The insulation on it will crack after a decade, and besides that, it just isn't right. The mil-spec wire can be ordered in bulk at a reasonable price....at a minimum go the distance and use that.

thanks for the information
 

Great information and thanks for the tips. I've looked at rewiring it, and actually have ripped most of the wire in the cab of my 52 out as it had been converted to 12 V and It would be easier to start with nothing than try and figure out what the previous owner did. (replacing parts with John Deere parts, and a keyed ignition). I found a schematic in an old US forestry publication that showed how to rewire it from 24 to 12 so will use that as a guide, providing I don't chose to return it to 24 V. That will be a few years down the road (One project at a time).

I found a few bare spots in the wires when I redid the fenders and tried to hook up the lights. After hooking up the horn I found that it went off when I made left turns. Since disconnected it as there no doubt is a bare wire somewhere there. I'm lucky in Saskatchewan an antique vehicle does not have to pass safety so can still take it down the back trails and rural roads. When I move to Manitoba it will have to be parked till I get this all fixed as it will have to be safetied unless i only take it to shows. Thanks again for the help!! :thup2: