When changing a watch battery, the actual act is fairly simple, but there are many things you need to be aware of beforehand to keep from damaging the watch movement. If you have a sport style watch or a watch with a digital display, you can expect to see a lithium battery in your watch when you open your watch case, be aware that you might also have to know How to Remove a Watch Band to open the watch. Once you open the case and can see the battery, if all you can see is a large cell strap you can assume that you’ll have some kind of a lithium battery under it. Follow these instructions to change your average lithium battery.
Once the back of the watch case is open, before you touch any part of the movement, you should put plastic finger cots on your fingers that might touch the watch movement. We recommend doing this because any dirt, oils or grease on your fingers can get on the movement and damage the inner workings of the watch if you touch it with your bare fingers. These finger cots will keep that oil from transferring to the watch.
Once you have removed the back, you may encounter a wide rubber or plastic gasket across the movement. When your fingers are protected with finger cots, remove it and set it aside so you can access the battery.
At this point, you will be able to see the battery. It will be held in place with a large strap that is a little like a cell strap except that it is larger and held partially under the battery. There may also be a sticker on the battery and strap with instructions for changing it. Watch movements are very delicate and you should use the utmost caution when working with them to avoid damaging or moving their precision parts. Be particularly cautious of springs that stick out.
Find where the strap locks into place. There will be a small opening in the piece that holds the latch down, take your non-magnetic tweezers and grip the metal latch piece in the opening. Carefully push the metal latch down with your tweezers before pulling them out toward you to release the metal latch.
Now that the strap is open, take your plastic tweezers and grip the battery to remove it. You may need your non-magnetic tweezers to slip the battery out of its slot before you can grip it with your plastic tweezers and remove it completely.
Examine the battery and find the replacement number on it. Lithium batteries usually have a four digit number preceded by two letters, generally CR, but they may also be labeled with a four digit combination of letters and numbers. Set the old battery aside, in case you need it again before you are done working on the watch. You may need to use the Watch Battery Replacement Chart to help you find the right size replacement battery for the job.
Once you have the right size replacement battery, take it out of the package and pick it up with the plastic tweezers. Make sure that the positive side of the battery with the engraved number is facing upwards. Carefully lift up the latch strap and slide the new battery under it and into the battery slot with the positive side facing upwards. When the battery is under the strap you may have to use your fingers to push it into place.
Then, take your non-magnetic tweezers again and grip the tab of the latch strap that locks into place in the movement. Holding the movement steady and in place with your free hand, reverse what you did to remove the latch –push it down and then back toward the battery until it slips into place.
Now that the latch strap is back in place, you need to restart the movement with the new battery. Take your non-magnetic tweezers and put one pointed tip in the hole marked as a negative charge. Place the other tip of your tweezers in the AC port in the movement. Once both tips of the tweezers are in contact with the movement ports your watch should be running again.
Next, if your watch has a rubber or plastic movement cover or gasket, you can reinstall it over the movement to keep it cushioned away from the metal back now.
When you are done, be sure to discard or recycle the old battery, as they can be toxic and dangerous, and replace the watch case back. For information on How to Close Your Watch Back, check out these videos.