When should you consider a C cell clock movement? The primary reason to use a C cell clock movement is longer battery life. Changing a common battery in your clock every couple of years is usually not a problem. But, when it’s in a hard to reach clock high up on a wall, or inside a case that’s hard to open or access, it can become a solvable problem. These larger C cell batteries simply store more electricity, so they last longer.
A C cell movement is larger than a AA battery powered movement. It has to be to hold the larger battery. If you have room for it in your case, you can double the length of time between battery changes,