Under the Caseback: My Watch Needs a Battery
A common Swiss Quartz movement.
Before watchmaking school, I worked as a repair technician in a service center. As a brand service center, we did all the steps. Watchmaking school only reinforced the reasons why we went to such lengths to ensure the watch was working properly.
The culture shock when I see the bare minimum battery change that’s done in department stores, jewelers, and home workshops alike need some awareness. People will still try changing their own batteries— I hope this article will help you succeed.
Here are the basics for those in home workshops without all the equipment needed:
It’s a cell, not a battery. Batteries are made of several cells.
Do not touch the cell with your fingers. Oils from your hands will shorten the cell life.
Do not grab the cell with metallic tweezers, they will short the circuit and damage the cell before it’s even in the watch. Use plastic tweezers, available on Amazon.
Keep that piece of film you see under the cell, under the cell. It’s called an insulator— without it, the circuit will short, and the cell will last only a few weeks.
Do not write on the inside of the caseback with marker. The marker chemically breaks down with age and reacts with oils in the movement.
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The steps of a proper cell service with the correct equipment:
Clean the caseback before opening. Often they are dirty and you do not want debris entering the movement. Alcohol and a cotton cloth work well. There is special tooling for snap-on casebacks or screw-down casebacks.
Remove the existing cell. Check the code on the cell to see its age— this will be a clue about how the watch is working. If the cell is new, something else is wrong… unless the cell was defective from the start.
Test the existing cell: with dedicated equipment, assessing the voltage of the cell will tell you if the cell actually died. If it died, you’re on the right track. If the cell is still at full voltage, something else is to blame for the watch stopping.
Test the consumption of the movement: using special circuit equipment, such as the Witschi New Tech Handy II. This allows visibility into the actual function of the movement. There are technical limits designed by the manufacturer that the movement must fall within— if the movement is consuming more energy than expected, it indicates that the movement is in need of a service. A new cell will not correct this problem, and it’s best to inform the customer and perform the service then. If the cell was simply replaced, the customer would return shortly, escalated, because the problem was never fixed.
If the movement is good to go: test the new cell. Sometimes cells are dead right from the package, we have to ensure it’s new.
Install the new cell, with the insulator in place if applicable, using plastic tweezers, and verify the watch is ticking.
Lubricate and install a new caseback gasket.
Pressure test the watch in a dry tester like the Witschi Proofmaster. Replace additional gaskets if necessary, like the crystal gasket and case tube gaskets.
Set the time and date before returning to the customer.
Changing the cell in your watch when the watch has stopped is important. If a watch sits too long with a dead cell, it can eventually leak and destroy the movement. At the very least, it’s important to remove the old cell until there is a better time to have the movement overhauled by a certified watchmaker.
If you go to a third-party shop, do your research. As them how they change a cell and if they have a certified watchmaker doing the work.
Cell, or “battery” changes are one of the most frequented services by the public. Unfortunately, they are often the most neglected and misunderstood. Quartz watches are awesome— let’s keep them ticking for as long as possible.
My goal is to help educate my readers so that you are able to make confident decisions. I encourage everyone to try a cell change on a watch that is inexpensive and without sentimental value before you try it on something important to you— and of course, professional services are preferred. When possible, I recommend sending the watch back to its manufacturer as they have all the parts to properly fix the watch to avoid the variation of service quality at third parties.
