I don't like disposable batteries and I do like taking my little Volca FM with me to my friend's place to jam. So here's how I installed lithium ion batteries and a charger.

I have done this to my Sample 2, Beats, FM, and Modular. The NuBass has an extra capacitor in it that needs moved to fit the mod.

Supplies

A soldering iron, some solder, hot glue gun and a #1 phillips screwdriver are needed as well as these supplies:

Battery LiPo 455272 : https://www.amazon.com/AKZYTUE-2000mAh-Battery-Rechargeable-Connector/dp/B07TTD39DP

Board: https://www.amazon.com/Lithium-Battery-Adjustable-Discharge-Integrated/dp/B091F5PTY2

2 x 1n4004 Diodes to drop the charger voltage: https://www.amazon.com/McIgIcM-1N4004-Rectifier-Diode-DO-41/dp/B0719667NK

Some 24 ish AWG wire and I used hot glue to secure the parts.

As seen in the photo this is how I decided to mount everything.

Step 1: Take Apart the Volca and Setup the Board

Remove all the screws from the back of the unit including under the battery door. Carefully split the case open.

Desolder the battery connection wires and tape them down out of the way. I cut off the ends to prevent sorts if any batteries are installed.

Step 2: Install the Board and Battery, Then Wire It!

First, solder the two diodes together with their stripes pointing to the (-) input on the board.

Then solder a wire to the (+) on the board and another to the end of the two diodes for negative. This then gets wired to the Volca as shown here by the pink (+) and white (-) wires.

With that done lay the board face down and the battery right next to it as shown. Put the Volca back together and make sure everything clears. I trimmed the ends of a pot soldered to the board down. Then I glued it all in place with hot glue.

Test the charging and output and that the Volca turns on the reassemble and enjoy!