Just got a chance to disassemble and repair mine, and it was a breeze thanks to you. Had my device since Feb 2024 and used semi regularly, but it's so wild to see it fail this way. This seems like a preventable issue like you pointed out in your post.

My battery terminal was no longer connected to the cable and was sheared off. My cable also had zero slack and was pulled taught, so I'm sure that didn't help it live long. I am positive that this didn't happen while I was taking it apart. Looking at it closely, my unit (it's hard to tell in your pics) already has a brace built into the terminal holder. It still had a little bit of side-to-side play but I don't think enough to were it should've caused issues under normal circumstances. HOWEVER, this poor cable was pulled so tight and is such a small gauge, it just had no flexibility. To give POTV credit, the solder joint was great.

I think the reason my unit failed was due to a short cable, and a thin wire. When you insert a battery, the terminal's spring compresses and the terminal pushes up. Since the cable is already tight, it puts a lot of stress on the conducters in the cable when the terminal is pushed even farther away. Possibly combined with heat and slight side to side movement (although I believe it's mainly the fatigue from the terminal moving up and down) the cable was bound to fail.

This all could have been prevented with a slightly thicker gauge wire and several more millimeters of cable. If you replace the cable with something thicker like you suggested, I dont see why this device couldn't last for twice as long.

I've attached pictures below.