[Sam] picked up a Sansa Clip audio player to listen to some tunes while working on projects. He liked the fact that he could run the Rockbox alternative firmware on the device, but thought the 15 hour battery life needed some improving. He swapped out the stock cell with a larger Lithium cell for a long life of 50-60 hours. It’s an upgrade fom 300 mAh to 1100 mAh, but as you can see, the size of the replacement made for some interesting case modification.
The battery swap required more than just taking one battery out and putting in the other. [Sam] is using a cellphone battery as the replacement and he didn’t want to have issues with the internal circuitry. He took the cell out of its plastic enclosure, removing the circuit board in the process. That PCB is the charging circuit, which he replaced with the one from the stock battery. After insulating the cell with a layer of Kapton tape he soldered it to the MP3 player and did his best to adhere all the parts to each other.
Sure, its ugly, but that makes it right at home on the work bench.