Replacing Rechargeable Internal Battery in SanDisk MP3 Player or Similar Electronics

I have a SanDisk MP3 player I listen to during my daily commute on the train to work. Mine's especially nice because it also has an FM tuner built in.

A couple months ago, the battery wouldn't charge all the way and would only give about 10 minutes of play time. So I did some research and found I could replace the internal rechargeable battery easily. It took me a couple of months to finally get around to it, but I'm glad I finally got to it.

For the SanDisk, the model number of the battery is BAK 3038p. I would think if you have a similar sort of player or small electronic device, you'll find you may be able to replace the battery as I did with my player.

Here's the player with the new battery on the workbench.

Unbeknownst to me, while the player was sitting for a couple months, the internal battery got puffy!

The fact that it pushed the case open a bit made it even easier to pry the case apart.

I used a guitar pick to pry the case open the rest of the way. You could use a small bladed knife or a plastic tool of some sort as well. I wanted to avoid hacking up the case in the process and the pick worked perfectly.

You will see there are two small clips on each side that hold the case halves together.

The battery is held to the circuit board with a piece of double sided tape. It just pulls up off the board.

Note the three small leads going to the circuit board. One of mine popped off when I turned the battery over, no big deal.

I used solder wick to get the leads off.

Make sure your iron's tip is tinned when you do this.

Gol-ly!

Lookit how puffed up the old battery (on the left) is puffed up compared to the new one. It didn't leak, but it looks a bit scary.

Note I marked the locations of the leads to the board in case I forgot where they went - Red, Blue, Black.

Solder the new battery to the connections on the circuit board. A tiny piece of insulation had already been stripped from each lead when I got it. Perfect, since the leads are so fragile and I would have been leery of having to strip the insulation off.

Since I had taken most of the old solder off, I melted a small bit of new solder onto each connection, heated the connection up, and pressed the lead onto hot solder on the board.

Not the preferred way to do this I know, but we're dealing with a small connection and it won't be under any stress.

With the new battery in place, I plugged the charging cable into my PC and tested the player.

As you can see, it worked!

Snap the case halves together...

...and you're in business.

The new battery already had about a 90 percent charge on it, so I could use the player right away.

Again, I suspect this method would work for a lot of small rechargeable electronics, as long as you can get a replacement battery.