DIY Power Box / Solar Generator – Lithium Battery Power, LLC
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DIY Power Box / Solar Generator

DIY Power Box / Solar Generator

Blog post written by Hank Vincent, Roto City Tech

Why build your own?

Building your own power box is not only fun, but it's a great way to utilize spare parts and have a way to power devices built by yourself.

List of items I used:
- 1 box (here is the one I used
- 2 on/off switches (
- 1 LED lights (
- 1 Voltmeter with amperage reader (
- 1 12v power plate (
- 1 6 way fuse block (
- 1 Solar controller (I already had one but here is a similar one
- Small screws
- Assortment of wiring connectors (
- Assortment of fuses that fit your block
- 1 In-line fuse (
- Crimping pliers (
- Battery of choice (I chose a 12v 12ah lithium ion battery from Lithium Battery Power.)

The Build

After deciding on the battery you will use, you will need to find a box that it fits in. Remember to have an idea of all the components you want in your box to be sure that they all fit. The box I used was small so it was tough to get everything to fit. In the end I'm happy with it's size and portability.

Firstly, I set my battery in the box on one side and marked a line on the outside, from top to bottom. This will allow me to know where I can mount all my equipment. I then started mounting the pieces starting with my solar controller and battery terminals. I simply screwed in the solar controller and drilled holes for the wires to go in. For the battery terminals, I had to drill a hole first.


The next step was to install my on/off switch. I messed up with this, but corrected it later on. I installed a huge battery disconnect switch that was overkill. As seen here, the battery disconnect is just too much. The switch towards the side is for my LED light and I ended up using another one of those switches for the on/off.

I then flipped the box over to install my 12v power section. To do this, I drilled two holes to slide the 12v power and USBs through and then screwed the faceplate in.

Below the power section, I decided to install the voltmeter. Once again, you just have to cut a hole the correct size and push it in.

The LED light is installed on the side of the box, I only needed to drill a small hole for the wires to pass through and then I screwed the light into the box. 

When it came time to wire everything up, I found that it was very difficult to get a good picture because of the size of the box. Here is that mess!

I used an in-line fuse from the hot side of the battery to the fuse block. From there, all the other pieces came off the fuse block. The negative side of the battery goes directly to the ground on the fuse block, as well as all the grounds from the different pieces of equipment. Depending on the pieces you want to install, there are many wiring diagrams that you can look up to get an idea. The only thing that does not go to the fuse block is the 1/4 inch battery terminals. They wire directly to the battery so that you can use alligator clips to change the battery in the box from charger or from solar panels. The other thing to remember is to loop the voltmeter amperage loop over the hot wire coming from the battery. That way, when you are charging something, the display will show the amperage being used.

Here is a crude wiring diagram based on what I did.

In the end, I will be able to connect my solar panels to the battery terminals to charge up my box, or I can plug in a wall charger at the house. My plan is to upgrade the solar controller because I am not sure how well this one will work with my lithium battery. So far, I have already used this to test the trailer lights on my DIY teardrop camper build. This should give me about 16 charges on my iPhone.

This was a fun project! I ended up cutting a piece of wood to cover the giant hole from the battery disconnect and I installed a smaller on/off switch. If I had to do this again, I would definitely use a larger box.