Pictures here: https://imgur.com/a/vEg8yy2

These parts can be used to make a 12V battery box using an Apache 1800 case from Harbor Freight. They're remixed from https://www.thingiverse.com/thing:5219823. I didn't bother modifying the inner ring since I didn't see a need.

Parts list:

Apache 1800 Case: https://www.harborfreight.com/1800-weatherproof-protective-case-small-black-64550.html?_br_psugg_q=apache+1800

Battery (this is the one I'm using, but you could use any of the same dimensions): https://www.amazon.com/gp/product/B097BRKCQP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Power Switch: https://www.amazon.com/gp/product/B07T1JG6BD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

XT60 Panel Mount Connectors: https://www.amazon.com/gp/product/B07YJMCDC3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Binding Posts: https://www.amazon.com/gp/product/B07PFMD1N2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

12V Lighter Socket: https://www.amazon.com/gp/product/B07H1MGWFN/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

12V USB Socket with Voltmeter: https://www.amazon.com/gp/product/B07FXH5ZZK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

M3 Hardware: https://www.amazon.com/gp/product/B078V3YCF6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

M3 Heat Insert Nuts: https://www.amazon.com/gp/product/B09KZSJS88/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

1/8in Thick Foam Strip: https://www.amazon.com/gp/product/B07SVCTB4B/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

You'll also need: Spade connectors, various lengths of wire,

Assembly:

Unfortunately, I have no pictures of the build process, but it's fairly straightforward and should be easily understood by looking at the finished product. Basically, everything is just getting wired together

To start, insert the M3 nuts into the holes in the rim piece. ORIENTATION IS IMPORTANT - compare this piece to the panel piece to see which way the attach. I just put them on the tip of my soldering iron and pushed them in. I'd recommend practicing this on a test piece to get a feel for it. It helped to have another metal tool to make sure the iron didn't pull them back out.

After that, clean out the inside of the box with some rubbing alcohol and add a few strips of the 1/8in foam to the bottom and sides of the upper right-hand corner of the box. Use the battery for sizing if necessary (the idea is that these strips will help provide grip to hold the battery in place once the panel is on).

Next, rough up the inside of the rim of the box; I used a rotary tool with a diamond bit (because that's what was on when I picked it up), and that worked well. Epoxy the rim in the box, clamp it, and allow it to cure. Use the battery to determine the correct height if necessary.

While the rim is curing, you can assemble the panel side. Look at the picture for where things are mounted. I screwed all the connectors in place, then wired them - that worked well for me. My wiring may be a bit haphazard, so feel free to improve on that if you know what you're doing. Additionally, I added some foam strip to the inside of the battery wall on the panel piece so the battery will have foam on all sides. Once the panel side is done, everything can be mounted and tested.

Bonus: you can mount a cheap Amazon solar charge controller in the lid for use with a solar panel.