M1078 (6) 24F Battery wiring.

[Sgthoffer]

Hi, I recently purchased the stuff to make my own battery cables in 1/0 stranded 99.9% oxygen free copper wiring and the lugs, crimpers, etc. I purchased 6 of the 24F Walmart maxx 750CCA batteries. Since the LMTV comes with 4 batteries instead of 6, can someone draw me a diagram of how I need to install the cables. I can follow directions perfectly but I am unsure of myself when it comes to the configurations the cables need to be in. Sorry if this has been discussed before but I could not find a thread on this specifically.

 

[Mullaney]

Hi, I recently purchased the stuff to make my own battery cables in 1/0 stranded 99.9% oxygen free copper wiring and the lugs, crimpers, etc. I purchased 6 of the 24F Walmart maxx 750CCA batteries. Since the LMTV comes with 4 batteries instead of 6, can someone draw me a diagram of how I need to install the cables. I can follow directions perfectly but I am unsure of myself when it comes to the configurations the cables need to be in. Sorry if this has been discussed before but I could not find a thread on this specifically.
View attachment 859840View attachment 859841

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Congratulations on the new tools! I know it gets cold in West Virginia, but the charging system on the LMTV will be happier and do a better job for you with two batteries. Doesn't have to be anything fancy... Higher CCA's will be better, but the two battery setup is better. On the inside of your battery cover - there should be a small yellow sign that draws out the 4 battery setup if you prefer.

 

[Sgthoffer]

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Congratulations on the new tools! I know it gets cold in West Virginia, but the charging system on the LMTV will be happier and do a better job for you with two batteries. Doesn't have to be anything fancy... Higher CCA's will be better, but the two battery setup is better. On the inside of your battery cover - there should be a small yellow sign that draws out the 4 battery setup if you prefer.

The truck starts off 24volts doesn't it and the 12v is for accessories and random components? I was going to have two batteries for starting and the other 4 for 12v accessories. Is this not common?

 

[Mullaney]

The truck starts off 24volts doesn't it and the 12v is for accessories and random components? I was going to have two batteries for starting and the other 4 for 12v accessories. Is this not common?

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Yes and No. Many owners of these trucks have stepped back to two batteries and been very happy. If you lived in Alaska, the extra cranking amps might be useful. Otherwise, two will be a good way to operate the vehicle.

By default the truck has 4 batteries. A group of 2 for 12v and a group of 2 for 24v. It definitely has a 24v starter. Most of the rest of the truck is 12v like the tail lights and headlights. The Neihoff generator creates 12 and 14 volt power to charge the batteries. It just does a better job with half the number of batteries. The transmission, heater blower, fuel, and air dryer heaters are all powered with 24v.

There is a really good thread about the charging system. Link below:

2009 Lmtv M1078A1 Charging System

Just saw your post. I have a 2007 A1 that the no charge light just came on. I’m wondering how you resolved your problem and if so share that with me. Checking the voltage on the two leads going to the regulator I have 24 V on the AC terminal and 0 V on the exciter terminal the one closest to the...

www.steelsoldiers.com

 

[SS WFO]

I am just getting started on my 1087 and its missing its 100amp reverse polarity relay. are these problematic?

 

[chucky]

I am just getting started on my 1087 and its missing its 100amp reverse polarity relay. are these problematic?

Given long enough they will cause problems if you dont keep the post cleaned for good connection. If you know for sure how to hook battery cables to your batteries without doing it wrong you dont have to have it just be careful while hooking jumper cables to your batteries ! put a meter on them if your not sure at first to know what is what .

 

[Ronmar]

The truck starts off 24volts doesn't it and the 12v is for accessories and random components? I was going to have two batteries for starting and the other 4 for 12v accessories. Is this not common?

Wow, completely missed this thread. It is not 12 and 24, it is 12 out of the middle of 24, as such, the alternator is designed to operate as a balancer, and to deliberately mis-match the battery is an extraordinarily bad thing to do…

12V doesn’t just power accessories and random components, it is all your lighting load, about 26A on a 1078, over 30A on a 1079. You only have about 60A max available on 12V and half of it is spoken for with that. Batteries are not power sources, they are temporary storage devices and ultimately loads. Because of the situation on these vehicles 12V is the last place I would ever add any load…

A standard lead acid battery wants 25% of the AH capacity in amps for the bulk charging phase(45% for AGM’s) the original battery was 240AH, so the battery is looking for 60A all by itself. Since you are pulling 25A for lights, the 12V is already 150% loaded. If the 12V side is pulling all it’s 60A, that only leaves 40A for the 12-24 side. Well it is also 240AH and is wanting 60A, so that side is now 150% loaded. That large a bank takes a lot of time to charge, so you got a long sweaty charging session ahead of you if the batteries get behind. Those alts are going for north of $2K these days, so…

The A0‘s also have a 12V vampire load, so it has always been a challenge keeping the 12V side at full state of charge with limited run hours. Batteries not kept fully charged sulfate and die long before they should..

The grossely oversized battery bank is the prime reason these vehicles have so many battery and charging issues.. This is the kind of error that class action lawsuits are made of, but get a pass in the land of milspec. They put a bandaid on it with the LBCD on the A1, but didn’t really fix it until the A1R with the introduction of the 260A alt, but they also fielded AGM’s about that time, so it didn’t really fix the root mis-match issue.

Cat specced a pair of group 31 batteries for these engines, and the 100A alt is a good match for a ~100AH battery bank When you factor in lighting loads.

I would wire a pair of batteries like this…

 

[BERZERKER888]

6 batteries is compete overkill and should you have the 100amp alternator, youll be chasing charging /electrical issues for ever...
here is a video of a more "appropriate" type 31 battery install..

 

[BERZERKER888]

I removed 2 of the 4 OEM 6TL batteries and wired in a battery disconnect and have had zero charging issues since..
Blue - 24v
yellow - 12v
red - jumper(fabbed up using leftover wire)
purple- main ground
green - battery disconnect ( I removed the NATO plug/wiring)..big thanks to Ronmar for his electrical help

 

[CONJIN]

I removed 2 of the 4 OEM 6TL batteries and wired in a battery disconnect and have had zero charging issues since..
Blue - 24v
yellow - 12v
red - jumper(fabbed up using leftover wire)
purple- main ground
green - battery disconnect ( I removed the NATO plug/wiring)..big thanks to Ronmar for his electrical help View attachment 861643View attachment 861644View attachment 861645

Awesome, thank you for the video and pictures. My truck came yesterday and I swapped out the 4 military batteries and put 2 group 31 batteries in. Started right up. Just ordered a battery disconnect switch

 

[SS WFO]

Hi, I recently purchased the stuff to make my own battery cables in 1/0 stranded 99.9% oxygen free copper wiring and the lugs, crimpers, etc. I purchased 6 of the 24F Walmart maxx 750CCA batteries. Since the LMTV comes with 4 batteries instead of 6, can someone draw me a diagram of how I need to install the cables. I can follow directions perfectly but I am unsure of myself when it comes to the configurations the cables need to be in. Sorry if this has been discussed before but I could not find a thread on this specifically.
View attachment 859840View attachment 859841

yea I gotta do the same thing and I am in need of a reverse polarity battery isolator

 

[B-Dog]

yea I gotta do the same thing and I am in need of a reverse polarity battery isolator

Just make sure you hook up the batteries correctly and move on. 1 less component to fail & 6 less connections that can come loose.