Dummy AA Cell

This is a dummy AA cell that can be inserted in a battery holder, with wires leading out a slot in the side of the phony cell to another power source or another component.

I used this to connect a bank of several AA cells in parallel to a wall clock that requires a single cell. Reaching the clock involves ladder gymnastics I don't much care for so I used this method to greatly extend the interval for battery replacement.

The photo shows a test with only one cell installed but the bank holds five.

In each end of the dummy cell there is a pair of 1.5 mm holes and a groove. I recommend using a 1.5 mm drill in a pin vise to assure the holes are properly sized. I see a tendency for small holes to print undersize.

At each end, feed a stripped wire end from the slot out one hole, across the groove and back into the other hole. Use enough stripped wire that the free end can be wrapped around the standing part and soldered. The loop of wire in the groove provides a connection to the battery holder contacts.

I used 26 ga. solid wire for this and it worked well. Larger wire would probably work up to the point the dummy cell becomes too long to fit the intended battery holder.

This model prints best with the slot up, using a brim. I tried printing it vertically with a support in the slot but the slot is so narrow removing the support was nearly impossible. Removing the brim is easier.

EDIT 12/31/25: Added rev 2 STL file. This version has a bevel in the pockets at the ends of the slot. It makes it easier to get the wire through by eliminating the square corners of the pockets.

Printing Notes:

Material: PLA Nozzle: 0.4 mm Layer height: 0.15 mm Shells: 0.8 mm Infill: 18% Support: none (use a brim)