The issue I was having is my dump trailer battery was only good for four or five heavy lifts, per full charge. The trailer is only a year and a half old, but I've moved thousands of tons with it. Since I am not great about charging the trailer off the house, I set up a solar panel with a voltage regulator. Unfortunately, it will keep a full battery topped off, but after one load, it really doesn't do much. Neither does the tiny wire from the truck through the 7-way plug-there just isn't enough to keep it topped off, even doing thirty minutes each way to/from the quarry.

I was on a job, where I was helping a guy who has a dump truck get a pad built in a short time period. I was only able to get two loads before the battery shot craps. After much research, I found even the best batteries only last a year or two of moderate + usage. For the price of a new battery, I was able to set up this 2 AWG system.

I used a kit I found on Amazon, but instead of a two-feet lead on jumper cables, I had eyelets put on. I also had to have a couple of feet added to each of the longer runs. The total cost, shipped, was around $125, and arrived in excellent condition. Here's the link, call for special orders and save on sales tax:

I didn't want the cables hot, while not connected, so I looked into a solenoid. The issue with a solenoid is the cost for continuous use and the issue of the trailer battery connector would still be hot. To solve both of these issues, I went with resettable and breakable circuit breakers, by each battery. I chose MP, from Waytek. 200 amp with 3/8" studs were around $37, each, shipped. I started with some cheaper ones, from Amazon, but sent them back due to coming with 1/4" studs. The MP are made in USA and substantially heavier built than the cheaper Chinese ones. Here's a side by side, of the circuit breakers:



I also order twelve inch 2 AWG cables to go from each battery to the other end of the circuit breaker.

From the battery in the truck:



Ignore all the electric tape. It's temporary, until I decide if I'm going to put another battery in the truck.

The cables are then routed through the frame and to the rear, by the hitch receiver mount, which is integrated into the flatbed.

Right now, the cables are not in a sleeve. This will be changed, when the weather gets nicer. I found some tubing that is flexible enough to work, but rigid enough to really protect the cabling. It's also very inexpensive, but not available locally. It comes in ten foot sticks and I will get some next time I go to the big(ger) city.

At the rear of the truck, I have the cable zip tied a few places. The end is just tucked up between the mount and the bed. Even if it comes out of its hole, it sits over a foot above the ground.



Here's how it looks, connected to the trailer. Enough slack to make corners, but not get in the way.





These are the connectors close up. They are Anderson 175A SMH and they are very sturdy, so far:





Then, after being connected, the 2 AWG goes into the trailer toolbox, through the factory grommet for the trailer wiring. The positive side goes to another circuit breaker, then to the battery. The negative side goes straight to the negative battery terminal. This breaker can also be thrown, so the plug will not be hot.



This tape job will likely stay as the trailer stuff gets bounced around much worse than the truck stuff. The small wires coming off the front of the battery are to the solar panel. I bought nice wires with plugs on those, too.

To compete this project, I set up my truck with a high idle. Even gas Ford Super Duty trucks come with an option for high idle. I have to be in park, set the parking brake, tap the service brake, then activate the first switch. This switch kicks the idle from 600 to around 900 RPM's. Once it's up to 900ish, I activate a second switch which is routed through a potentiometer. I can spin the pot to change the high idle from 900 to around 2,400 RPM's. This is in case I find the need to keep the 2 AWG connected, while running the pump or if I have a winch connected (the winch is a Warn 9000 and draws a lot of juice).

How well does it work? No idea. Since I got all this done, I haven't had any jobs.

 

I ran a cable like this to the rear of my truck and my dad had one on his old one and I'm getting ready to put it on his new one.
He has a winch on the front of his equipment trailer, rather tan put a battery on the trailer he had decided to run it off of his truck. He had the cable powered straight off the battery and live all the time on his old truck, I put mine on a heavy duty relay with a switch in the cab to turn the relay on or off and I will do his new one the same way.

 

Same/very similar, except I did mine for an in-box connection (gooseneck), and didn’t run two cables all the way from the battery (probably should have, but so far so good). Did the short cable off the positive side of 1 battery (crossover cable should be big enough to handle whatever you could put to it), used the Chinese CB 😉, and a single 1/0 back to the front passenger bed corner. Punched 2 holes in the inner skin in a protected-ish spot, grommeted the holes with some split heater hose, and ran the power and a ground cable through, ground connected to the frame. The pigtail in the box is about 4’ long, enough to reach the gooseneck hitch, but I also made an extension with 2 more plugs to reach the bumper. I’ve used it for more than I thought I would, great way to power a slip tank pump, jump/power a welder/generator, etc. Also made up a set of jumper cables (clamps on one end, plug on the other) intending to jump cars on a trailer (used to haul a lot of auction cars/projects, easier than swapping a battery), but found they work really nice in parking lots, too, park crossways in front of a car. I later added a 3-way splice under the cab to the power cable, and ran it through the floor to power a fairly big inverter under the seat. Personally think both the big cable into the bed and a big inverter should be standard equipment!!

 

Nice work! I know what you mean about trying to supply a lot of juice to the trailer. The large wire is one sure way to get power back there with minimal voltage drop.

Just beware that you are loading your vehicle power system quite a bit - namely your alternator and voltage regulation. It is one thing to have a way to charge the trailer battery off the truck, but the energy you are using for the pump/trailer has to come from somewhere - and the source of that is the alternator - regardless of what RPM you run the engine at. Yeah, higher RPM will get better output from the truck's charging system - but you may need to beef that up as well.

Those circuit breakers should not be used as disconnect switches. They are only rated for so many cycles and using them as switches will accelerate their wear. If you do use them as switches then have a set of spares at the ready to swap in, otherwise you may encounter some down-time or find you have to jumper across them to get juice (circumventing the whole idea of having them there).

In any event, it all looks good. Post back and let us know how it holds up when you get to give it a work-out.

 

I only plan to run the pump off the truck, if I have to. Only one or two dumps I may not even plug it in. If I need more power, plugging it in, while traveling, to keep the battery in the trailer topped off, is my next step. Then, unplug it when actually powering the pump. If I have to, the option is there to leave it live, with the truck running to help power the pump. The only time I plan to really give the truck power a workout is if I put the winch on, which will not have it’s own battery.

I’m not too worried about the cycles, there won’t be that many. We use a similar setup on our patrol vehicles and are instructed to kill them at the start of our days off. We keep our assigned vehicles two to three years, so they get a lot of cycles, say between 100-150, minimum, in the life of the setup. I haven’t heard of any giving issues. My use will be much lighter than that. If I was using it every day, I would make a different setup, to kill power. Yes, if it fails, I can bypass it, I made sure I had enough cable to get to the battery, if I had to direct wire.

Good points.

 

I need to get some jumper cables for it, could have used them, today, to help someone where I could only get my truck backed in.

Something like this should be a factory provided option, but if course, you’d never make everyone happy.

I love the versatility this setup gives me. It could be used in a huge variety of applications. I hope I actually get to use it...my health is fading faster than expected.

 

Like the idea. Wondering if you could just get a single 2 ga wire and run it from positive terminal to back end and then get a ground just long enough for what you need and ground it to the rear of the truck?

i know this thick wire is expensive so shortening the ground will save $$.

 

Yes, that would work, but it is more stable to have it go back to the battery. So many problems are due to poor ground, I don't want to have this be another one.

 

I got a new winch mount and was able to use the rear power plug, to get the winch cable back in. It was a mess and needed oiled, so we took it out and did that. We used a Polaris Ranger down a hill, to keep the line tight. It worked well with two of us and my friend's son steering the Ranger. I used my high idle at full whammy, 2,400 RPM. IT went easy. I could probably use a lot lower RPM, but for the first test, I didn't want to bog anything. Now, I want to get a front 2" receiver and put another plug, in the front grill.

 

good point.

in your original post you mentioned a inexpensive sheath not available locally to protect the wire as you run it through the frame.
Couldn’t you use 1/2” conduit?

 

Each cable is over a half inch OD and they are connected. The route I used has a lot of turns, to secure it and put it where it was as best protected, as possible. What I found is flexible, but a lot stronger than wire loom. I don't know what, exactly, it's called. I saw it last time I was at Menards, but didn't want to mess with it, on that trip. When I get it, I'll let you know what it is and how it works.

 

awesome. TY 👍

 

I betcha that what you found was "drip line". Available in many sizes and has good abrasion resistance. I use it all the time as a "poor man's conduit".

 

I’ve had some time to test this setup. I’ve been on a few house demo’s, hauling to the dump. One evening, I made about fifteen trips, in a couple of hours (taking stuff less than 1/2 a mile). It did great. Instead of wearing the plugs out, I just leave them connected, unless I’m taking the trailer off. Thus far, there have been no issues. The cables don’t get hot, to the touch, or any other red flags. Often, I don’t use the high idle as I have plenty of battery, for one lift, knowing it will charge on my way back to where I’m going.

 

I'm adding a DC to DC charger to my 5th wheel batteries. The 7 pin does not give me enough charge to run my absorption fridge on AC more than 4.5 hours on the road with 2-100 amp Lithium batteries. Using a 50 amp fuse at the truck battery and a 50 amp out of the DC charger to the Positive bus bar in the RV.

2 gauge back to a 175 Andersen plug next to the trailer plugs in the bed, 4 gauge from the bed to the RV DC charger.