2021 Ford Ranger FX4 TRS-3 Project Build

[Jim Oaks]

Remote Lithium Battery / DC to DC Charger

I had thought about sticking a battery in my trucks toolbox to power an air compressor, and now that I have a fridge to go in the bed, it just seemed to make more sense.

I started out with a Universal Battery Mounting Tray. I like this thing because it bolts to the back wall of my toolbox and has side protection. I was able to mount the battery on the shelf where the fire extinguisher was mounted. I also found that I had room to mount the fire extinguisher standing up.

I needed to add a 60-amp circuit breaker close to the main battery and then run the power from there back to the bed. I took some flat stock, bent it, drilled some holes in it, and bolted to an existing bracket on the tray where the fuse box is mounted.

​

Then bolted my circuit breaker to that.

​

I shopped around trying to find a battery cable crimper. All the part store had was the kind you stick on a vice and hit with a hammer. Even Harbor Freight didn't have one, so I ended up buying an iCrimp battery lug crimper that came with a cable cutter from Amazon for $34. Money well spent. I also ordered an Anderson 50-amp quick disconnect and a package of terminal connectors that came with heat shrink.

You just dial the teeth to the cable gauge you're using. For this job it's 6-gauge wire.

Cut it, crimped it, added the heat shrink, and installed it. Then I had to make a short cable to go between the circuit breaker and the battery.

I ran the battery cable and a ground cable through the plastic plug in the bulkhead of the bed. They pop out and snap back in. I added a rubber grommet before installing the wire.

​

The ground goes down to the cab mount bracket on the frame. There's already a hole there. I just had to sand the point off, add a terminal stud to the ground cable, and bolt it down.

I installed a 50-amp Anderson connector so the toolbox could be unplugged and removed if needed.

​

The battery cable and ground wire go into the Anderson connectors which then connect to a Victron Isolated 30-amp DC to DC charger.

​

I mounted the charger under the side lip of the toolbox and then ran the wires through rubber grommets into the toolbox to a 100Ah Lifepo4 Lithium Battery. There's another 60-amp circuit breaker (the Victron instructions call for both of these 60-amp fuses / breakers) inside the toolbox that the positive cable goes to and then goes from there to the battery.

I also added a fuse block and a dual 12-volt outlet. I have a small inverter that I can plug into the outlet. The idea behind that is that I can set my Jackery 500 Power Station back here and charge it much faster with a 110V AC inverter than I could from a 12V DC outlet.

​

I installed (2) SPDT ON-OFF-ON toggle switches. In the photo above they're in the off position.

The one on the left powers the 12V and USB outlets on the front of the toolbox. This is where my fridge plugs in. If the switch is flipped to the left towards the front of the vehicle, the fridge is running off the battery in the front. If the switch is flipped to the rear, the fridge is running off the battery in the rear of the truck. While traveling it will run off of the main truck battery. When I stop to camp for the night, I'll flip the switch and run it off the auxiliary lithium battery. Nothing to unplug. The next day I'll switch back to the main battery and let the lithium battery charge back up while I'm driving. Between this and my Jackery 500 Power Station I should be able to run my fridge for at least a few days without starting my truck.

The other switch is for the LED light strips in the lid and on the front of my toolbox and is wired to work the same way.

My Smittybilt air compressor is wired to the battery as well. There's a 50-amp circuit breaker just off the battery that the compressor is wired to. I know the compressor has a built-in circuit breaker, but I decided to add my own.

Now if I need air, I just open the toolbox and turn it on. No more lugging it to the front of the truck, opening the hood, and having to connect the cables to my battery.

 

[Jim Oaks]

Today I mounted a Harbor Freight Apache rifle case in my metal basket. This will give me a waterproof storage space up there. I also got one of their large cases that fits up there too, but that one will get strapped down so it's removable.

 

[Robertmangrum.rm]

I've seen several guys drill some holes, and u-bolt them down. Then, fill the holes with some silicon or something. When my box was up top, I used wire ties on the handles to hold it down. That way, I could access the inside without removing any straps. Im sure you thought of that.

 

[Jim Oaks]

I like to use j-bolts (that's how my traction boards are mounted) but I had (4) mounting brackets that came with the basket to mount it to the bed rack that I reused. They're about a 5-inch square u-bolt that sits flush inside so I don't have any threaded bolts or nuts sticking up through the bottom. One of those situations where you save something odd thinking some day you'll use it.

 

[Robertmangrum.rm]

I like to use j-bolts (that's how my traction boards are mounted) but I had (4) mounting brackets that came with the basket to mount it to the bed rack that I reused. They're about a 5-inch square u-bolt that sits flush inside so I don't have any threaded bolts or nuts sticking up through the bottom. One of those situations where you save something odd thinking some day you'll use it.

I don't have a clue what your talking about, haha I dont save anything

 

[Uncle Gump]

I have a bucket full of things like that...

 

[sgtsandman]

I have a bucket full of things like that...

While not a bucket, I do have a kid's tool box, some regular cardboard boxes, and some organizer trays full up miscellaneous hardware from past projects. It is getting to the point where I need to start going through some of it and toss it.

 

[Snoranger]

I have a bucket full of things like that...

Where’s Rick? He’s got a garage full of those things.

@Rick W

 

[sgtsandman]

Where’s Rick? He’s got a garage full of those things.

@Rick W

I thought it was a shed? But then again, a shed can be pretty darn big.

 

[Rick W]

Who? Wha.?!?!?? Wasn’t my fault!! It was the guy behind me.!!!

Obviously, I have not been in the middle of this thread. First, let me say congrats to @Jim Oaks. He put that extra battery in his toolbox almost the exact same way I put mine in, except he did everything by the book and showroom quality. I’m jealous, it looks fantastic, and I’m sure it works just as well. I don’t think I did anything unsafe with mine, but it’s definitely more Rube Goldberg.

And there’s an old saying, “a penny, saved, isn’t worth the effort!” (or something like that). I do tend to save everything, way beyond anything I would probably logically ever use again. Having said that, there are so many times that I go digging in one of my junk boxes and I find the exact right size shape material and color item I want to do a particularly weird thing. I could’ve never afforded to do the Road Ranger or the Missing Linc or a dozen other projects if I had to buy every little bit of it, and they’d never get done from running back-and-forth to the store.

Having said that, I’ll reflect a couple things. My second battery is a deep cycle marine battery. I have a manually operated disconnect switch, and you guys advised me on putting in one of the automatic low-voltage cut off switches between the two batteries. If the voltage on the first battery drops below 12.4V, it automatically disconnects from the toolbox battery. You don’t have to think about it, and the truck will always start. I think it was about $20.

You guys also advised me that the toolbox might not be an ideal location because you could get buildup of hydrogen gas. My box is far from airtight, but it’s an excellent point I haven’t really addressed.

And this comes from doing an emergency response to traffic accidents and the hazmat stuff: the fire extinguisher shouldn’t be inside the toolbox, it should be much more accessible. If the electrical by that second battery starts fritzing out, that’s going to be a hard extinguisher to get near. Mine is mounted to the outside of the toolbox, outside the battery, but mostly because that’s right next to the driver door of the truck. It’s held very securely in place with a few zip ties (somebody would have to work hard to steal it), and I have a screwdriver right there I can use to break it loose if I need it quickly. I’d hate it if it got stolen, but I’d hate myself even more if the truck was burning down and I couldn’t get to it.

Another thing I keep in the shed of miracles, are literally trash bags full of different kinds of foam rubber. There’s the white very high density rubbery foam, typically used for packing electronics or ceramics, that is worth it’s weight and gold. Oil resistant poly. You can shape it very easily, and you can glue it together with E6000/goop. My battery and some of those electronic things around the battery all have about an inch of that foam around them in almost every direction. Jim’s toolbox looks a lot neater than I’ve ever thought of keeping mine, but we throw stuff in there without thinking, and it bounces around as we go down the road, and it will be bouncing around on those electronics and that battery. That little bit of foam buffer goes a long way to prevent a problem from a misplaced loose tool.

I’m also a junkie for collecting old diamond plate truck toolboxes. My purchase price range is usually zero to $25. I use the lids for trailer fenders, I cut the corners out for different kinds of protective boxes, and I even cut the back sections off of one to the make the light housings for the Road Ranger. To run my train horns, I had to use two of the little air compressors that come with the air horns, put relays to them, and merge the airlines. I cut the corner out of a scrap toolbox and then mounted those air compressors in the opposite corner of the truck toolbox, and used that cut out corner for a cover. Indestructible.

I could go on and on and tell Jim how to do this thing, but I also think it’s important that the young guys learn for themselves, make their own mistakes. But I’ll be keeping an eye.