conversion of 4 batteries to 2?

kc5mzd

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Glow plugs are on the 8xx series I have 818 tractor and 820 van. The 9xx series is still wired the same way less the glow plug wire. Don't know about a blower wire, I thought they used a resistor off the 24v supply to get low speed?
 

Ford Mechanic

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All of the M939 series do not have glow plugs. They have ether assist. The blower just hooks to one battery (12 volts) to get low speed. No resistor involved.

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Voyeurger

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I use 2 group "31s" batteries in my 5 ton. I live in central TX so I don't worry about starting in cold weather. The "s" in the battery size makes it come with studs instead of posts. I threw out all the battery terminals and saved the nuts. I bolted the wire directly to the battery studs with the nuts and have never had to worry about loose terminals. The studs seem to hold everything together better and fits the stock wires. I only have 2 batteries and usually start the truck at least once every 3 months or so (unless it is cold outside).I would strongly recommend using 2 12 volt battery chargers or maintainers instead of 1 24v. With one charger wired to each battery you will be able to balance the charge and both batteries will last a lot longer. A couple of cheep charger / maintainers from Harbor Freight should work fine. Even the expensive ones from Amazon are often made in China anyway...
Great advice kc5. Plenty of room in the box. Appreciate it.
 

Voyeurger

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A 3rd hot wire would go to the glow plugs. It hooks to the + on the battery that goes to the vehicle's ground or frame.
Sorry to appear dense KC, but I have two cables from the slave and two from the truck. Do the slave cables only serve jump assist or are they also part of the 24V system? Is truck ground slave cable or truck cable negative? Is starter slave or truck positive?
Gary
 

Ford Mechanic

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No problem, glad to help.

So your slave cable is a completely stand alone function. It's just for jumping the truck. Think of it as fool proof, no way to mismatch cables and cause a fire/explosion etc... You don't even have to hook it up if not needed.

I didn't understand part of one of the previous post. But the truck is a negative ground system. If that's what you were asking.

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Voyeurger

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Jbulach,
Yep, I was worried about clearance between the battery terminals and seat underside so I got low profile batteries (NAPA Part # 7251 @ 7 15/16 H)
Thanks for the heads up.
Gary
 

Voyeurger

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No problem, glad to help.

So your slave cable is a completely stand alone function. It's just for jumping the truck. Think of it as fool proof, no way to mismatch cables and cause a fire/explosion etc... You don't even have to hook it up if not needed.

I didn't understand part of one of the previous post. But the truck is a negative ground system. If that's what you were asking.

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Holy CRAP! The light comes on! I was terrified of running a conflict thinking I was dealing with two separate voltage systems coming out of the box! Knowing the slave cables have that single purpose just took a load off pal.
Thanks again!
Gary
 

Voyeurger

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My solution to the clearance issues. Relocation! Easier to replace also.


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Yeah, but then you don't get to hoist the monsters up into the cab, over the sheet metal box frame while simultaneously keeping the cables at bay!
Your solution is brilliant. Are the stock cables long enough to get them to the tackle box? Nevermind! Don't want to know. The monsters are resting comfortably in the box and I ain't moving them till they die.
Thanks Bud.
 
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Ford Mechanic

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Yeah, but then you don't get to hoist the monsters up into the cab, over the sheet metal box frame while simultaneously keeping the cables at bay!
Your solution is brilliant. Are the stock cables long enough to get them to the tackle box?
Thanks,
Well I found no need for the slave cable cause that one wouldn't have been long enough. But the main cables were. I did have to lengthen the 12 volt blower wire. There is a knock out at the top left of that under cab box that I used.

It was the first mod I did to the truck, it was almost out of necessity. I had to pull the seats to remove the floor mat, and I cussed those batteries! I had 2 6tl hawkers in it at the time and thought I was going to have to get the loader to help get them out. So there was no way they were going back in there.

That pic is from last month when I finally had to replace the hawkers,(yes 2 of those big ones will fit in that box, barely) I used the group 31's from Napa $100 each.


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TwistedOaks

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I went to a relocation too. But I couldn't stand the lower toolbox. It constantly leaked, and the door never shut right. So I went this route... Box from Northern Tool - rear cowl from West Marine. Marine 5200 sealant around the cowl, then bed-liner paint.

Used a switch from my s280 shelter, wired to a 8" 12v led bar I got on amazon for like $12 to light it up when the door opens.

Haven't quite tightened up the extra wiring yet. Still need to get my protective boots on the lugs too. Built all new cables and cross connects. Also set it up with a switched isolator, so I can run on battery set "A" most of the time, while set "B" sits there on the Solargizers. For a long trip, I'll switch to A+B and let the alternator do it's thing. Nothing worse than not being "mission capable" due to a forgotten light switch.

Trays are amazon too, ($8 each i think) but of course, for 31 series batteries, the tiedown "knobs" didn't fit. So I fabbed it out of a strip of aluminum to lock it all down.

Next is adding the isolator and breaker system for the Warn 18k winches.

IMG_4759.jpgIMG_4760.jpgIMG_4758.jpgIMG_4764.jpgIMG_4767.jpg

Edit: almost forgot the purpose of my post... I too was switching to 2 battery setup, but found that short runs to Starbucks, etc. the alternator either wasn't happy about it, or the size of my batteries was off, or whatever, and would occasionally leave me stranded when I left the running lights on for 5 minutes. (30 minute runtime, could leave the running lights on all night and and still start right up... assuming i have a dying alternator). So I just felt a lot more confident using the 4 battery system. Maybe if I had a spare M939 or 24volt vehicle to slave to I'd feel different? :p
 
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Voyeurger

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TwistedOaks,
THAT is a thing of beauty! I would go so far as to say elegant.
Very nice work. Great minds (you and Ford) think alike. A spare 24 volt vehicle? I don't even have the jumper cable.
Gary
 
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