Wiring issues??

morrisles · Unread post by **morrisles** » October 20th, 2009, 1:50 pm

Im new here and I just got a m151 jeep and as you know it has a 24 volt system with 2 batteries wired in series to turn the starter. It has 1 wire ran from the first battery to the ignition and then the distributor, fuel pump and lights all run from there on 12 volts. But as you guessed it is draining the first battery. It also as what I thought was the starter solenoid but it may be a series parallel switch (after I have looked online more); that has 24 volts from the batteries going in, 12 volts from the ignition going in, and 24 volts going out to the starter; with the alternator wire connecting to the same pole as the battery cable. I hope this makes sense. and any help would be great.
1. Does it have a starter solenoid?
2. How can i keep the batteries charged?
3. Is there a way to wire it up without using a voltage reducer to run everything on 12 volts?

Rainman · Unread post by **Rainman** » October 20th, 2009, 2:30 pm

Hey Morrisles,
Welcome to the forum. I'm only on the welcoming committee

, but the experts will be here soon to answer all of your questions.

Any chance your going to take it back to all 24v, or is your plan honestly to take it all to 12V? Electric fuel pump would sound like your working on an M151A1. The more details you offer up, the better understanding your experts will have of your situation. Oh, and pictures, pictures are good thing.

Rainman

muttguru · Unread post by **muttguru** » October 20th, 2009, 2:39 pm

morrisles wrote:Im new here and I just got a m151 jeep and as you know it has a 24 volt system with 2 batteries wired in series to turn the starter. It has 1 wire ran from the first battery to the ignition and then the distributor, fuel pump and lights all run from there on 12 volts.

Welcome to the G838. Please don't take this as questioning your knowledge of the vehicle, but are you SURE that the system has been modified to 12 volts? (in other words, does the feed wire connect to the "+" side of the battery that has its negative terminal connected to the body?

morrisles · Unread post by **morrisles** » October 20th, 2009, 3:48 pm

I'll take some pictures tonight and post them up. I bought this a few months ago for the hunting lease; so there is not alot of extras on it. Just the batteries, alternator, distributor, ignition, fuel pump, headlights, and the solenoid (which I think is the series parallel switch). Here is the wiring diagram I drew up....and I'm not an expert on drawing but i hope it makes sense.

SEABEE62 · Unread post by **SEABEE62** » October 20th, 2009, 4:15 pm

Welcome aboard.......Seabee

Fil Bonica · Unread post by **Fil Bonica** » October 20th, 2009, 4:48 pm

All stock 151s are 24 volt. There are no series parallel relays used in them. If your Mutt has it then it was a "bubba" special.
In the interests of simplicity it would be my suggestion that you consider returning it to that configuration.
Then there are no problems with charging , starting or troubleshooting.
Just some words from an old man.

Fil Bonica

Ralph Fuller · Unread post by **Ralph Fuller** » October 20th, 2009, 7:55 pm

Welcome to the site. Here is a wiring diagram for a M151A1:

raymond · Unread post by **raymond** » October 20th, 2009, 8:06 pm

Once you become familiar with it, you'll find the 24 volt system is no more intimidating than a 12 volt system. In fact, the military used better wiring and insulation on that wiring than you will find in most civilian wire harnesses. If someone hacked the wiring, It was probably someone who just didn't understand the 24 volt system, or they just didn't want to order any parts mail order. Parts are easy to be had and are not too expensive. I would attempt to put it back to 24 volt if at all possible.

Oh, welcome to G838

Ralph Fuller · Unread post by **Ralph Fuller** » October 20th, 2009, 8:12 pm

Batteries installed in running MUTTs
A-1

A-2

svramselaar · Unread post by **svramselaar** » October 21st, 2009, 4:57 am

hello

it is possible to get a car to start on 24 volt and all other electric users on 12 volt
the generator or alternator must also be 12 volt
for the relays see below

http://www.pjldiesel.com.au/docs/47.pdf

the mutt do not use a starter relays
you must put a starter relays in place of the food starter switch

Bosch use from the starter button to the relays wire nr 50
from the relays to the starter wire nr 50 A
(the Bosch relays has two big 80 amp fuse`s if one is melted and you try to start it sound like a machine gun )
you can see a spare on the left below side on the drawing and the two in use at the side`s

the US type use from the start button to relays nr 4
to starter relays nr 7

in normal use the two battery`s are parallel at 12 Volt
only if you start they switch to series at 24 Volt

Thad's all to it george

svramselaar · Unread post by **svramselaar** » October 21st, 2009, 5:20 am

hello again

if you want know if the mutt is on 12v look at the generator or alternator if it is a 12volt or 24 volt
see also if the ignition is getting 12v or 24v
horn lights and so
if they only have take 12v from one battery for litle items as a radio or else you can use a 24v to 12v converter
it is easier to let the mutt 24 volt

for a converter see below
http://shop.ebay.co.uk/sis.html?_kw=Tru ... AT+NAV+etc

george

morrisles · Unread post by **morrisles** » October 21st, 2009, 9:06 am

svramselaar wrote:hello

http://www.pjldiesel.com.au/docs/47.pdf

the US type use from the start button to relays nr 4
to starter relays nr 7

in normal use the two battery`s are parallel at 12 Volt
only if you start they switch to series at 24 Volt

Thad's all to it george

The US version of this looks just like what i have on it now. Except it has 24v going in the bottom pole from the battery and the alternator is connected here as well and then 24v going out the top pole to the starter. Then it has a ground on a pole and the wire from the key ignition switch to another. (Im going to try to put a picture on here but I dont know if it is going to work.) If i do wire it up the way it is showing to wire it up with the batteries in parallel - Where does the alternator hook up to? But of course I would have to get a 12v alternator. Which would not be a bad thing if I can just get 24v to run the starter and everything else is 12 volts and it will keep the batteries charged.

What I do know is the alternator and starter are both 24v. But the distributor is running on 12v (which I know originally is 24v but it runs fine on 12v). Then I have the headlights and fuel pump on 12v. Im guessing who ever had this before wired up things just to make it work. But like i said i use this for hunting and Im trying to get it not to die on me again 2 miles from the truck....its not much fun walking in the dark 2 miles in the mud.

Im going take the 1 battery back today and get another to see if that helps (which it could just be a bad battery).
Im going to try to post some pics on here but it may not work from my work computer; if not I will post them tonight.
I really approciate all the help you guys are giving me on this issue. I hope I can get this solved soon.

Cobra5 · Unread post by **Cobra5** » October 21st, 2009, 10:15 pm

Welcome aboard morrisles.

SEABEE62 · Unread post by **SEABEE62** » October 21st, 2009, 10:20 pm

Welcome Morrisles.....Seabee

Rainman · Unread post by **Rainman** » October 21st, 2009, 11:02 pm

Hey morrisles,
The pictures did not come through to me at least. If you are having picture problems, send me a PM, or email the pics to me and I will post them for you.
Rainman

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