Box Truk - Solar Panel Project

Thread for the Solar Panel project on the Box Truk! I will include the wiring and DC voltage systems that will power and store the energy on the box side of the truck.

3300W of Solar panels
10kWh of Lithium Batteries at ~48V
3000W Inverter

This is in progress. I am currently working on the “Shore” power hookup. Shore power is just plugging your RV into the grid.

I am planning on two different 120VAC 30A hookups. This way the RV hookup can be on either side and I don’t have to crawl under the box and pass a cable under.

Transfer switch to toggle between the two sources looks like this.

Then I am using a Bluesea ELCI (RCD / GFCI) to do the current limiting.

This is the plate I designed that will mount them to my electrical panel.

Going to 3D print it out to check fitment then get it laser cut out of some aluminum.

I found this neat article on how to implement “reverse” polarity indicators for the shore power.

This basically lets you know if the shore power you hooked into has a voltage potential between the ground and neutral.

3D printing the plate for mock up. I have to wait till Monday anyways for the circuit breaker I am using.

Will see how the tolerances work out. Probably cut the electrical panel door this weekend.

Panel looks good!

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Roughed in a wiring diagram for this part of the Box Truk. Straight forward but wanted to make sure I wasn’t missing anything.

Here is the panel with all the components installed. Need to do the wiring and cut the door on the electrical panel to install.

To pass power from the outside plugs to the inside I drilled a hole in the floor and put in this wire gland designed for the hulls of boats. Seaview CG30P-G

Here is what the sockets look like under the truck. These are Nema SS2-50P which seems to be the “standard” for RV hookups now days. I wont be pulling 240V 50A but 120V 30A but I wanted to make sure I was using a more modern connector so I don’t have to use adapters all the time.

Shore power completely wired up.

This is between the box and cab bulkhead area where the wiring comes up from under the truck.

Putting in the selector switch and main A/C shore power breaker wiring.

Testing how much current I am pulling up the A/C shore power wires.

To get the solar panel power into the truck, I am reusing a preexisting hole. This is where the Satellite Radio antenna used to go. Glue down the bulkhead fitting with some 3M 5200 UV sealant.

Then I added a 48V DC cooling fan for the electrical box.

The fan is a Delta FFB0848XH and I am using this PWM controller I found on Amazon.

Got the A/C selector switch panel and the breaker/switch panel cut out of aluminum from Send Cut Send.

Cut up the door on the electrical panel and gave it some white paint to match the inside of the box.

3D printed breaker blank plates. If anyone is interested I can upload the design file / stl for this.

Then I ran conduit from the solar panel power entrance to the box to the back of the electrical box. Ran 10AWG 1.2kV specced wiring through this.

Then mounted the 48V to 12V power supply. Starting to get crowded in this box and I haven’t even started putting in the breakers and switches.

The cheapie V/A meter I picked up works pretty well. It reads current via a shunt on the negative battery cable.

I picked up the 8020 (1020 and 1030 extrusions) from a local supplier and started mocking up the solar panel rack with the help of Mike.

Cutting the extrusion.

Fresh blades that are designed for the material make a difference!

First bracket!

Rail and brackets on the passenger side of the box up and on.

Driver side.

Getting the cross beams on.

Prepping the solar panels by lengthening the wires on the panels.

First panel up on the rack.

5 out of 6 panels on the rack and connected to the charger.

We got power.

What is next is to bolt down the panels to the rack, do cable management for the panels, and figure out how to make a slider system so my last panel can slide under the rear 5th panel for travel / storage and then slide out when parked.

Thinking on some nylon 8020 sliders similar to these.


And then make it powered with a outdoor rated linear actuator.


Though I dont think the nylon sliders will really like the weight. Does anyone know if there is something like a linear bearing that can handle being outside 100% of the time? Maybe with a grease insert?

A rail system like this would work great. Similar to a garage door track / wheel system.


McMaster carries similar things under track guides but they are $270 per 8’ rail.

Wonder if there is a cheaper alternative. :slight_smile:

unistrut with a roller trolley setup maybe?

These work well in dirty environments.


As much as I want to over complicate this slider… 48" drawer slides are under $150 a pair…

I got the 5 panels on the rack bolted down today.

And it was the first somewhat sunny day since I plugged the panels in so I got to see some decent charging off the panels.

While I had the ladder out I measured up the front rail and panel to design an air deflector to keep wind from going under the panels at highway speeds.

Made it into 3 pieces with the idea being its bend out of 1/8" Aluminum sheets.

Firing off the send cut send cannon!

Picked up the aluminum extrusion for the 6th solar panel slider.

Drawer sliders arrived as well. Super beefy 48" sliders. We will see how long the mechanisms last outside. People on overlanding forums use these all the time on trailers and truck beds so I suspect they handle the elements better then I imagine they will.

While I am wrapping up the solar panel aspect of the build, I am starting to work on the truck side again.

One of the requirements I set out was to be able to charge the batteries and run the A/C in the box side while driving down the road.

I went over lots of different options but I have settled on using the eg4 all in one battery charger/ solar controller to handle the 48V lithium bank all by itself instead of having a separate charger that runs off the truck system. I will run a 3000W inverter off an upgraded 12V Truck system (either bigger single alternator or get an auxiliary second 12V alternator) which will feed into the eg4 charger.

This simplifies what devices need to talk to each and handle loading. I loose a bit of efficiency from the inverter but the truck only gets 13mpg so it probably wont really be noticeable.

The inverter can only be active and charging the lithium bank when the engine is running, driver turns on a switch on the dash, and selects the A/C input to the inverter on my electrical panel I made.