This is a case for UPS module that I bought on AliExpress: 15W 3A 18650 Lithium Battery Charger Module DC-DC Step Up Booster UPS Uninterruptible Power Supply - [https://s.click.aliexpress.com/e/_Eue6MmZ](https://s.click.aliexpress.com/e/_Eue6MmZ)

I remixed the original model and improved it a little bit, here's a list of changes:

-Added more space inside the case, so you don't have to force fit the module into the case, making it more usable in case you need to do some modifications - solder wires, replace batteries, etc.

-Added more material to the top and to the bottom, so it's not flexing so much and is safer to use (lowering chances that impact damages batteries or electronics inside)

-Added chamfer around the edges

-Reduced size of holes and screws required, so there's more material around the holes for the screws to hold on

-Removed unnecessary empty spaces inside to make it more solid

Bill of material:

2.5 mm x 14/16/18mm self taping screws (4 screws)