What is it?

Makers, hackers, prototypers - we often cobble together a system from existing parts on hand, or spend some time analyzing a system and need to get our fingers (and test tools) inside the gear. These little dummy-battery items make a bunch of things easier for us.

Note: see AA, AAA and CR2032 coin-cell versions in my Tindie store.

Hack a battery interface - Say you have a 4-cell battery pack, but your circuit only needs 4.5 volts. Four cells (4 x 1.5) is nominally 6Volts, but replacing one of the batteries with a shorted-out dummy will give 4.5V instead. Short out two positions for 3V etc.

Analyze a circuit - Perhaps you have a device running on a two-AA battery pack and you want to measure the current. Use a 3-cell pack instead, and replace one battery with an open-loop dummy. You can put your meter in series easily to test the current consumption.

Inject external power - Maybe you have a device that uses up expensive batteries and you want to use a wall-wart supply instead. Use an open loop dummy battery, plus a shorted cell in a two-cell pack which lets you inject external power. [CAUTION - don't mix external power with an actual battery]

Analyze prototype behavior - to analyze the operation of a device as the power fades out, or perhaps to chart power usage in different operational modes. You could use one open-loop dummy battery, and shorted ones for any other positions. This way you can use a combination of external power, volt meter, ammeter etc to do a thorough analysis.

Why did you make it?

In many situations I found myself soldering up test wires on new prototypes. With a couple of dummy cells I could switch quickly between test and operational mode with my projects.

What makes it special?

Its simplicity is what makes it great. No fancy components or complex hook-ups, just pop it into your existing gear without wasting time.