What is it?

Like my other dummy batteries, it's a simple substitute for a coin-cell that allows you to test a circuit without needing to solder or rig up awkward wires in some way. If you're making a new custom circuit, you could have an unknown short that you might not notice until you power it up with a real coin cell. Using a dummy insert, and a current-limited supply you can easily catch the fault before it becomes a problem. Another application is to simply use it with a meter in series with your power source to test the current consumption of your device or circuit. Yet another use is to power a circuit from a different battery pack, maybe to provide longer life, for example. Works great when your device (or its battery access) is in an awkward location. I use one in a garage-door-ajar alarm for example. A handy and inexpensive little solution to a common problem.

The item is a 3D-printed disc of precise size, with a copper wire-threaded through it to cover all the key contact points on various coin-cell holders. (There are many different battery-holders on the market, so you may need to rotate the dummy cell a bit in yours to get optimal contact).

Why did you make it?

I first needed a dummy CR2032 coin cell to test current consumption in a battery-powered device. Later I wanted to rig up a long-life battery (AA cells) instead of the coin cell. With that product selling very well, I had requests for other sizes, like this 2450 size one that I hope solves a problem or two for your projects.

What makes it special?

It's a unique and accessible solution to a common problem when you're making a new devices or hacking an old circuit. You need to see what the power supply behaviour is, or you need to get more power into an awkward spot, or a myriad of other challenges. Just popping one of these in can solve the problem quickly. Shipped pre-threaded with solid 24AWG wire and 10cm (4") long wire tails, so you don't have to do the fiddly bit.