Replacing a watch battery is a DIY project within the capability of anyone. For about $10 in tools (the cost of a typical battery replacement at the jeweler), you can have a fun time doing it yourself. The only reason why you may NOT want attempt it is if you are worried about accidentally scratching the back's finish.
If you want to give this project a try, you will need two tools. The first is a small screwdriver or a pin-retractor. The pin-retractor will make taking the band off much easier. The other tool is an adjustible case opener. This tool is used to open the back of the watch.
To open the case, adjust the case opener so all the pins are aligned with the channels on the back of the case. Rotate the tool counter-clockwise to open.
Once the back has been removed, you can see what type of battery powers the unit. In this case, it is a Renata 399 button battery. Most watch batteries are easy to find. However, if you want it cheap, get it on EBay. We purchased ours on EBay for about $0.25 each.
Replacing the battery is a simple matter of popping out the old one and putting in the new one. Before taking out the old one, though, do note the polarity (+/-) orientation. Trust us on this little tip. - Wan Chi Lau (permalink)