New M-1083 owner. So, here we go!!

[Ronmar]

PVT Snuffy strikes again!

I have found plenty of that on my truck - a 2008 with 1500 miles on it. My grid heater was wired to the 12v side of the LBCD. Just recently found that my air intake elbow at the turbo was on backwards. Had my truck a year and still finding PVT Snuffy's calling cards.

Yea don’t take anything for granted. I found brake shoes installed backwards…

 

[RRaulston]

Runs long enough to get outta my sight, its good to go!
One ground goes to the nato plug and the other ground goes to the instrument shunt below the polarity protection device. From the instrument shunt the ground lead continues on to the main ground terminal on the front of the starter casing. If you are making new cables, I suggest you remove the shunt and its two cables and replace it with a single cable from battery to starter ground. The shunts sole purpose is to measure current flow and provide that info to the STE cannon plug under the left side of the dash, that no one ever uses… While you are in there, clean and inspect all the connections on the polarity box. They are out in the weather and a known source of problems…

I will now climb onto my high horse and tell you to remove two of your batteries. They are gross milspec overkill. The fact that they only provided a 100A alternator to maintain them is the kind of engineering mistake class-action lawsuits are made of, but occasionally fly in the land of milspec. IMO it is the primary reason these trucks have so many electrical issues. They tried to mitigate this failure by installing a different device where the polarity box is and a disconnect relay to disconnect the batteries from an overloaded alternator so the batteries don’t kill it.

They finally addressed the issue on the A1R by shifting to a 260A alt. But they also started shifting to AGM batteries that draw nearly twice the current of flooded lead acids, so they didn’t really fix the issue.

They are demanding gold plated prices for the 100A dual volt alts, so do yourself a favor and better match the batts to the alt. Cat specced a pair of group 31 100AH batts for these engines. A pair of the original batts(120AH) will work OK with the 100A dual volt, and significantly ease its workload and potentially extend its life…

OK. So, let's do 2 batteries. I'm assuming I'll keep the inner 2. (Closest to the frame.) can you point me to a basic diagram? If you notice the above pic, the frayed wire and broken terminal were on the 24v positive terminal? (Positive on the inner left battery) ... So those wires, I'm thinking will stay there. All the negatives will move to the negative on the right-side battery and the Positive lug on the right-side battery will go to the left batteries negative?? Right?? we can do this!! I think. And you think the existing batteries will be adequate. The previous owner put them a year ago at the cost of about 1k....

 

[coachgeo]

..... After reading a ton of threads, the consensus was to make sure the....

Massive appreciate you doing your due diligence and checking out past threads and videos so you come in here with either solutions or "informed" question. Especially also not with "repeated for the millionth time question(s)".

Keep it up. Your truck is in good hands.

 

[coachgeo]

OK. So, let's do 2 batteries. I'm assuming I'll keep the inner 2. (Closest to the frame.) can you point me to a basic diagram? If you notice the above pic, the frayed wire and broken terminal were on the 24v positive terminal? (Positive on the inner left battery) ... So those wires, I'm thinking will stay there. All the negatives will move to the negative on the right-side battery and the Positive lug on the right-side battery will go to the left batteries negative?? Right?? we can do this!! I think. And you think the existing batteries will be adequate. The previous owner put them a year ago at the cost of about 1k....

just had same question asked in DM lol. passed this too him

 

[coachgeo]

 

[Ronmar]

The normal layout has ground furthest away from the frame, 12v in the middle and 24V closest to the frame. So you would keep one inner and one outer battery.

a year old, they may be OK. Fully charge them and let them set overnight and compare voltages. You can also take them to a autoparts store and load test them.

2 batteries will charge faster and have a better chance of staying at a full state of charge. Low state of charge causes sulfation and is probably the biggest single killer of batteries. The A0 has a small 12v vampire load so a small balancer and maintenance charger is also a good idea…

 

[RRaulston]

View attachment 884167

wow, your pulling the 12v from BT1 negative. Interesting....

 

[RRaulston]

Someone from here drew this. I forgot who but credit to him. Get rid of NATO Plug and do a disconnect. Room in front of the battery box for a tender and Ronmar's equalizer mod? Maybe carry a spare battery. going to order some oo cable and connectors. ill order enough cable to be able to bypass the shunt. I think the plan is coming together. Thanks for taking the time to give input...

 

[coachgeo]

wow, your pulling the 12v from BT1 negative. Interesting....

that is from a post here on SS....

With the positive of the battery below it is already connected to that negative shown as the 12v pull out; it should work. So that makes the lower battery the 12v source.?? it is just attached indirectly.

Ron apparently did the same thing in his as well.

New M-1083 owner. So, here we go!!

PVT Snuffy strikes again! I have found plenty of that on my truck - a 2008 with 1500 miles on it. My grid heater was wired to the 12v side of the LBCD. Just recently found that my air intake elbow at the turbo was on backwards. Had my truck a year and still finding PVT Snuffy's calling cards...

www.steelsoldiers.com

 

[RRaulston]

just had same question asked in DM lol. passed this too him

Great video!

 

[Ronmar]

wow, your pulling the 12v from BT1 negative. Interesting....

It doesn’t really matter, with the jumper, they are basically the same point electrically. I reused one of the original jumpers with a threaded stud on either end. Not sure exactly which end it is connected to right now

Mine had 2 basket case batteries in it. Put in a pair of group 31’s to start it in the auction yard and drive it up onto the trailer, still have them there…

 

[coachgeo]

It doesn’t really matter, with the jumper, they are basically the same point electrically. I reused one of the original jumpers with a threaded stud on either end. Not sure exactly which end it is connected to right now

Mine had 2 basket case batteries in it. Put in a pair of group 31’s to start it in the auction yard and drive it up onto the trailer, still have them there…

was my understanding correct that in your and the other diagram the bottom battery is the 12v load battery?

 

[Ronmar]

was my understanding correct that in your and the other diagram the bottom battery is the 12v load battery?

Yes. voltages are referenced to ground so the battery attached to ground must be the lower potential/voltage battery.

 

[RRaulston]

What a day. Have you ever seen the video where the marathon runner is leading the race then 5 feet from the finish line he falls and someone else wins??! Yep, me. Today I tore out the batteries. Drove to Napa and bought everything I needed to convert to 2 batteries. Made the cables, charged up the batteries, removed the Nato plug cables. While the batteries were out, I cleaned the shunt and the box next to it. Every connection was nasty. I then followed the cables to the alternator. Cleaned those cables as well as the ground strap. Somewhere I read to remove the little wafer fuse on the 24v post. Then I fell..... While tightening the 24v post on the alternator, the post broke off. There was enough thread for one hand tight turn and done. No way it will hold long term with all the vibrations. Sucks to be me. But let's not get down. Fired up the truck and its charging like it should be. The gauge reads lower than my meter, but she works!! I am assuming I did everything right or something would have fried. And I'm beat. Thoughts on what to do on the 24v post?? Thanks....

 

[RRaulston]

Here is a shot of the batteries that are supposed to be a year old. Also a pic of the shunt. The shunt is on my list to be bypassed. OO battery cable is $10 a foot at Napa. I was going to get the whole 50-foot roll and replace everything until he said it was $500..... Uh.... NO...

 

[Ronmar]

Here is a shot of the batteries that are supposed to be a year old. Also a pic of the shunt. The shunt is on my list to be bypassed. OO battery cable is $10 a foot at Napa. I was going to get the whole 50-foot roll and replace everything until he said it was $500..... Uh.... NO...

Yea, if I read that date code correctly, they were a year old in 2010… They are also AGM’s AGM batteries want 45% of the battery AH rating in amps from the alternator during the major portion of the charge cycle. Plain lead acids want only 25%. So with the 4 battery 240AH AGM bank that was 108A just for the batteries… 2 batteries at 120AH is a much more manageable, but still pretty high 54A out of the alternator. The issue really is the 12v lighting loads. It is around 26A with all the lights on, so if you let the batteries get behind, dont run the lights till they are topped off

and when these fail put in a pair of group 31s. 100AH plain lead acid, commonly available/less expensive, and will only want 25A out of the alt. They will charge much faster if discharged and put way less stress on the alt…

 

[RRaulston]

Yea, if I read that date code correctly, they were a year old in 2010… They are also AGM’s AGM batteries want 45% of the battery AH rating in amps from the alternator during the major portion of the charge cycle. Plain lead acids want only 25%. So with the 4 battery 240AH AGM bank that was 108A just for the batteries… 2 batteries at 120AH is a much more manageable, but still pretty high 54A out of the alternator. The issue really is the 12v lighting loads. It is around 26A with all the lights on, so if you let the batteries get behind, dont run the lights till they are topped off

and when these fail put in a pair of group 31s. 100AH plain lead acid, commonly available/less expensive, and will only want 25A out of the alt. They will charge much faster if discharged and put way less stress on the alt…

Thank you for your words of wisdom!

 

[RRaulston]

Ok fellas, what's the best way to replace this stud??

 

[coachgeo]

Ok fellas, what's the best way to replace this stud??

what kind of break? as in did stud break off with part of the stud still there.. orrr??

 

[coachgeo]

.... I cleaned the shunt and the box next to it. ..... Somewhere I read to remove the little wafer fuse on the 24v post. ..

Wafer fuse?