I got this idea wanting to revive my old PSP 2000 but when I googled it people already made even more configurations of batteries, also found an instructable for a PSP 1000 by TailsL pretty good job: https://www.instructables.com/id/How-to-Fix-a-Psp-...

Supplies

Some things are needed for this project:

-Soldering iron https://amzn.to/3hOhR9R

-Soldering wire https://amzn.to/3hLV52u

-Paste Flux https://amzn.to/3hPKTWE

-Not working PSPbattery

Step 1: Open Up the Battery

-This job is pretty easy, plastic is very thin so just pry it open with a flat head screwdriver just be careful not to damage the board inside

-On the photo I marked positive and negative terminal don't get confused or you could damage the PSP

-Cut off the nickel strip from the old battery and this step is done

Step 2: Soldering

-Solder the positive wire to the positive terminal and negative wire to the negative terminal, it's not rocket science

Note: I'm using an old battery from a Chinese battery bank but I believe its a non branded 18650 battery I recommend to check the battery voltage when fully charged look for a maximum of 4.2 volts

Step 3: Placing the Battery and Bonus Tip

-Using one half of the battery case makes it easier to place the board and play without disconnecting the battery, secure it in place with tape or any product of your preference(hot glue, electrical tape, super glue, etc.)

-Connect the charger for the first time turning it on

Bonus tip

If you don't have a working PSP charger you can use a cellphone charger brick with an old USB cable (Recommended 5v - 1A or similar)

-Cut the end off and strip the black and red wire

-Use alligator clips and hook the positive to the charging port and negative to the outer metal connector on the top of the PSP with help of a USB cable

Step 4: Results

You can tinker with battery configurations you can use rechargeable AA batteries in series, 18650 batteries in parallel the only limit is your imagination.

Enjoy playing your favorite games and thanks for reading!