What is it?

This item is a breakout board for a dual 6.8mm coin cell battery holder (bare PCB, battery holder not included). The two coin cells are connected in series via the PCB traces.

The solder pads for both coin cell holders are located on the same side of the PCB. Through-holes are available for hand soldering wires.

Though-hole solder points are available on both terminals (+/-) of both coin cells. This allows the user to decide whether they want to populate a single coin cell or both coin cells.

The footprint used is compatible with the coin cell holder cage of part number BK-879 (shown in finished assembly picture). This was the part used to test this breakout board, which could be easily soldered by hand. You do need to hold the soldering iron onto the fins for an extra few seconds, as the metal cage acts as a pretty good heat sink.

Tested with the coin cell battery AG1 LR621. This battery size fits properly in the BK-879 holder and has a snug fit. I use a toothpick to eject the battery.

Why did you make it?

I made this to test a low power microcontroller board that stays in sleep mode for weeks at a time.

What makes it special?

Cheap and hand solderable.