Here’s a cool apple hack on how to replace the cells in your Apple Powerbook G3 if your batteries keep running out of time.
I decided to get new replacement cells from Battery Space instead of surplus cells at a slightly better price elsewhere. There are nine 18650 Li Ion cells in each battery, so I ordered 18 of them at a cost of about $100 with solder tabs. When they arrived, I carefully followed the instructions here to disassemble the first battery. It looked identical to the one in the photos there as you can see below.