18650 battery pack for PlayStation Portable systems (PSP)

Bought my first PSP 15 years ago and still use it today, but the batteries are obviously not working anymore. There are a few tutorials showing how to mod a bigger LiPo pouch into a PSP by removing the UMD drive, but I had plenty of 18650 batteries around and wanted to use one of them.

So, as there were no 18650 battery packs for the PSP, here's mine!

The door is remixed from https://www.thingiverse.com/thing:5385165  , to which I've added a 18650 battery tube and cap.

ONLY DO THIS IF YOU KNOW WHAT YOU ARE DOING. 18650 batteries and LiPo packs are dangerous and very flammable. I AM NOT RESPONSIBLE FOR YOUR ACTIONS OR PROJECT.

Rough instructions:

• print standing up, with supports (so the latch part is at the top)
• remove supports and process as much as your skills allow you to; printed parts aren't as smooth as injection molded parts, so use sandpaper in various grains gradually, especially on the latch (it will catch and be difficult to release) and the tube exterior (as this is where your hand will rest)
• take your old battery pack, crack it open, cut the old LiPo pouch and desolder the metal strips
• drill two holes in the battery case, top part; best choice would be into the two small circles below the PCB, as close to the edge as you can
• solder two wires (positive and negative) to the PCB terminals and pull them out through the battery case
• assemble back the battery case (feel free to use padding, hot glue, whatever you want)
• spot weld two strips to the 18650 battery positive and negative; the negative is obviously not important, but on the positive one you might want to insulate under the strip with another layer of tape, since it will be bent over the edge and downwards, increasing the chances of a short
• soldering the bottom (negative) will be easy and safe, but soldering the top (positive) will be trickier, as you don't want to solder with the upper strip next to the insulation (risk of melting the 18650 wrapping and shorting it out); I'd recommend to leave the positive wire a little longer and pull it out through the 18650 tube, then solder it (look at the pictures)
• carefully bend the tabs in place and insert the 18650 into the tube
• place the cap (it should stay in place just with friction, if not - drop a drop of cyanoacrylate glue on the edge) 
• install battery in the PSP, attach the door on carefully (guide the wires into the free space with a toothpick if needed)

Ta-da!

Interestingly enough, the pack works just fine on a PSP-2004, but a PSP-3004 doesn't want to start with it (nor charge it). No idea what could be the reason, as the PSP-3004 works just fine with a regular battery - if anyone knows the reason, please let me know :)