24 Volts to 12 Volts How is this done ??

[1953M-37]

It stop raining and I got to look at the M37 closer [It is out side] . It looks like to much of the wireing is gong for the 24 Volts and I just want to run one battery. So what do I have to change out ? And I will have 24 volt parts to sell. Thanks..... Miles.....

[Cal_Gary]

You'll need:
12v starter (that matches your 146 tooth flywheel)
12v alternator
12v bulbs
12v gauges

And replace all of your tired old wiring. I used a Painless Performance harness with their GM light switch.
I'd also recommend running two 12v batteries wired parallel as opposed to one (mine is a bit of a hard start when hot so I like the extra cranking capacity).
Gary

[powerwagontim]

I have an NOS 12 volt distributor, looks exactly like the stock sealed M37 distributor if you are interested. Or, you can swap all of the electrical components inside your distributor with 12 volt parts. (coil etc.)
PM me if you are interested.
Tim

[k8icu]

Get one 24V battery if you don't want to run two. Otherwise anything that is electrical on the truck will need to be changed to 12V. But other than not wanting to have to get two batteries why do you want to change to 12V?

[Tom @ Snake River]

If you have a fairly stock M37 DON'T DO IT, your much better off as far as value, ect to leave it origional.
However on the otherhand, when you swap in a modern engine and want updates, then switch to 12v.

[cuz]

Here are a few helpful sites:
http://www.novak-adapt.com/knowledge/12_volt.htm
http://www.garbee.net/~cabell/12voltconversion.htm

This is a very good US Fire Service PDF on serveral options for converting military trucks 24 volt to 12 volt.
http://m37.crwdesigns.com/electricconversion.pdf

[1953M-37]

The M37 is mostly stock but wiring parts are missing. If I get stuck and need a jump start what do I do ? I have a veteran friend that wants me to keep the M37 stock so I'm leaning to stock. Today My veteran friend took a dent out of the hood. One down many more to go... Miles....

[cuz]

If I get stuck and need a jump start what do I do ?

Even though often a jump with 12 volts can get you going it is unfair to the good samaritan to expose him to the risk of damage to his electrical system. You simply need to get two 12 volt batteries from someone and place them together in series with one set of jumper cables and then use a second set of jumper cables to attach them your system.

Or carry a 24 volt or two 12 volt or one 12 volt (if you're not in a hurry) charger with you.

Or pull or push start the truck

[ZGjethro]

I carry a 12 volt charger which has a high output mode for jumping cars. I have used it on one of my batteries when they were connected in series and it was enough to start the truck. I can also charge the batteries individually if needed. One of the 12v started packs could help also if you are not near a power receptacle.

My truck also has a battery tender wired into both batteries (24v). I do not use it very often though

[m37jarhead]

I suppose there are some advantages to switching from 24v to 12v but I'm at a loss to justify the expense and hassle to make the switch. So, the cost of all the 12v items tht you'll need is far more expensive than just maintaining the 24v
system and keeping it in good order. 24v parts are readily available. While not always the least expensive items to buy,
they're probably at least in line with current maintenence parts on modern vehicles. Have you bought spark plugs for your
late model pickup lately or replaced any fuel injection parts? Hold on to your wallet there.

[MSeriesRebuild]

Tom Howell has offered the best advice thus far in this thread.

Also worth mentioning is the fact that the original 24-volt system in a top notch condition is far more reliable than any 12-volt system you can put in place on the original engine. There are also upgrades that can be done to the original system that will make it even more reliable.

Concerning getting a jump for the 24-volt system; in the vast majority of cases, 1 battery being weaker than the other will be the case when it doesn't start due to a weakened battery condition. Simply hook a 12-volt jump to only 1 battery. If that is the good battery, nothing will happen; simply change the jumper cables over to the other battery, in most cases when the weaker battery gets the jump, it will fire right up. In a very few cases do both batteries fail completely at once; if they do, there is usually a charging system issue in play or some other issue that is causing excessive draw and battery discharge. In a well maintained vehicle with good wiring and battery cables, if you are paying attention, you will most likely get warning signs before you get left stranded anyway.

[Sal]

Also worth mentioning is the fact that the original 24-volt system in a top notch condition is far more reliable than any 12-volt system you can put in place on the original engine. There are also upgrades that can be done to the original system that will make it even more reliable.

Charles, What are the upgrades that can be done ?

Sal

[cuz]

Of course if you left something turned on then both batteries will dead.

Upgrades are alternators, pointless ignition, modern headlamp bulbs (with replacement elements), LED tail and marker lamps, addition of battery disconnects and etc.

[1953M-37]

Here are a few helpful sites:
http://www.novak-adapt.com/knowledge/12_volt.htm
http://www.garbee.net/~cabell/12voltconversion.htm

This is a very good US Fire Service PDF on serveral options for converting military trucks 24 volt to 12 volt.
http://m37.crwdesigns.com/electricconversion.pdf

This is grat information !

[1953M-37]

The starter . Should I have it changed from 24 volts to 12 volts ? Or can I buy one to run off my key switch and not the foot switch ? Miles......