FMTV Battery hook up diagram

Several threads mention a battery hook up diagram is on the backside of the battery box cover. Seems that is not always the case. None on this one and have searched the net a good bit but can't find a pic of one either. Am working on one now where batteries where pulled for charging and now doubting the memory of how they go back in (4 12v Bat.)

I know there is a 12v side and a 24v side so want to get it right.

Can someone point me to a thread I may have missed that shows this or maybe shoot a pic of their box cover diagram?, draw one up? or offer a clear pic or if their bed is off offer up a pic of battery arrangement birds eye view?

Certainly would appreciate it.

Here you go. from a M1078. I recommend printing and taping inside your battery cover.

Here's my version from a M1078A1

bikeman said:

Here's my version. lol.

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Is that from an A1?

mkcoen said:

is that from an a1?

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nfc

bikeman said:

nfc

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Sorry but I have no idea what NFC means.

mkcoen said:

Sorry but I have no idea what NFC means.

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National Football Conference?

mkcoen said:

Sorry but I have no idea what NFC means.

Click to expand...

No fraking clue. I took it last year out at DRMO when someone was looking for the image/diagram. literally turned over a battery lid, grabbed a pic, and put the lid back, didn't even look at the truck.

Bikeman's is from A1 with battery disconnect.

Okay so now we have both diagrams in one thread.

mkcoen - M1078
bikeman- M1078A1

mkcoen said:

Here you go. from a M1078. I recommend printing and taping inside your battery cover.

View attachment 641652

Click to expand...

Not sure if anyone saw me, but I was the ******* that died on I-75 in Richardson, in DFW, Texas, a couple of weekends ago. Yes, 5pm Rush Hour traffic, and it just died, right in the middle lane. A big Thank You to the Richardson PD for helping my dumbass out!

I was trying to make it home to Plano, Texas from Waco. Holt Cat in Waco had just put in my High Speed HWY Gears, so I made a run for home. Before I left, my batteries were bad, but jumpable. Holt Cat wanted to sell me (4) $500 AGM 6T batteries. I was planning to put in new 24F batteries when I got home. In transit, I carried a portable battery jump pack, which I started the truck easily with. My problems started when I hit Rush Hour traffic, and my speed was stop and go. I noticed my gauges stopped working. After that, it died, and it was no longer jumpable. Had to get towed off the road! Ugh!! Long story short, I had to hitch a ride home, and come back the next day, 12 miles from home. Next day, I put in New batteries, and it was all good. Fired right up - Boom!

I have not had the chance to check my voltage outputs yet. My Alternator is the N1511. I have noticed that my Voltmeter reads low though.

Anyway, is this a typical behavior? Basically, idle speed was not enough output to run the lights, let alone put a charge on the batteries.

The above is my battery configuration, so I can deduct that the batteries charge from the 28VDC circuit? The 14 VDC circuit just runs lights?

Since the LMTV's originally came with the 1500 Series of Niehoff alternators, can I swap in any other Military Series Niehoff, or are some Series a better fit than others? Would an N1224 (140 amp 14 VDC/260 amp 28 VDC) be better than another with 50 amps 14VDC/200 amps 28 VDC?


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The alternator is dual voltage and charges both 12 and 24. Chances are you lost your regulator 24 volts and the alternator is not exciting. Take off the 2 leads going to the regulator and tape them off. Take the 24 volt connection on your fuel solenoid, usually the outer connection, but verify with a meter to be sure. Connect and come around the front of the engine to the forward terminal on the regulator. Don't use the back terminal.

Suprman said:

The alternator is dual voltage and charges both 12 and 24. Chances are you lost your regulator 24 volts and the alternator is not exciting. Take off the 2 leads going to the regulator and tape them off. Take the 24 volt connection on your fuel solenoid, usually the outer connection, but verify with a meter to be sure. Connect and come around the front of the engine to the forward terminal on the regulator. Don't use the back terminal.

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I will try that tonight. Thank you!


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Just a shout out for United States of Freight: Joey's the best!

Sorry wrong thread.

Are the cables label?
My cables aren't connected to anything and I am trying to sort things out.
Are there connection points that I can trace back to ensure that the cables aren't crossed?

Does this drawing represent the way to connect two group 31 batteries or are the connections different?
I don't want to damage anything by hooking things up wrong. My goal is to connect two group 31 batteries, while maintaining the 24 volt and 12 volt circuits.


Thanks,

24v positive is towards the back, 12v lead goes left to right between the 2 battery rows and the lead at the outer end of the batt box is the negative.

Suprman said:

24v positive is towards the back, 12v lead goes left to right between the 2 battery rows and the lead at the outer end of the batt box is the negative.

Click to expand...

Is this description with the two batteries pointed port starboard or fore and aft?

All batts sit positive left forward towards frame

Suprman said:

24v positive is towards the back, 12v lead goes left to right between the 2 battery rows and the lead at the outer end of the batt box is the negative.

Click to expand...

I went to the truck today and I am starting to understand what you are saying.
The problem is I don't know which leads are positive and which leads are negative.
The only wires that are color coded seem to dead end at the NATO plug.

I am trying to lift the cab (hand pump) to trace things out but I have a nut that is leaking fluid hydraulic. It is a huge nut located between the cab and the bed. I tried to tighten it but it has a whole in the center that allows fluid to leak.

https://www.youtube.com/watch?v=2R5mtn0KAFo

If you watch this video pause it at the 13 sec mark.....the nut in the middle of picture is leaking fluid. Sorry for the confusing description. How do I stop this from leaking so that I can raise the cab and get the battery wiring figured out.

Thanks