LR44 / AG13 / A76 battery to wire adapter

Adapter for using an external 1.5 V power supply with devices that normally use LR44 / AG13 / A76 batteries.

Printed in PETG, 0.12 mm layer height, no supports.

A 4 mm wide, 0.1 mm thick nickel strip is required (the same type used for battery spot-welding). These strips are easy to find on AliExpress https://aliexpress.com/w/wholesale-4mm-nickel-strip.html and other sites.

The photos show how to orient the strip inside the printed part. I start by making a 90° bend in the strip, then push that end into the adapter, wrap it around, and press the rest into the slot. The “clamp” part (printed in TPU) helps keep the strip tensioned while soldering (photos show older variant of the clamp; files include new one). The second strip can then be pushed in from the bottom of the adapter and bent into place with a screwdriver.

Solder quickly—ideally with additional flux—because PETG melts easily. Pre-tin the wire with solder before attaching it to the adapter so the joint can be made faster. If you melt the adapter slightly it usually won’t matter; the important part is preserving the shape of the original battery.

Note: “+” is the large face / outer rim. “–” is the opposite face, on the smaller center contact (not the rim).

Last photo shows adapter inside example device (that normally uses two LR44 in parallel).

Source CAD files (Fusion and step) are included.

Example devices that use this adapter: