If you rely on your watch for the time, it can be frustrating when it stops working. The good news is, you don’t always need a professional jeweler to get it ticking again. Knowing how to change a watch battery at home can save you a lot of money and hassle, and it’s easy enough that anyone can do it. We’ll show you how!
What kind of battery do watches use?
The batteries in watches are much smaller than those in other devices. Called button or coin cell batteries, they’re the small discs you see in the battery aisle alongside the more common AAAs and AAs. Most watches use just one battery, though some more complex models require two.
Button cell batteries are typically non-rechargeable, and their usable life varies depending on the chemistry and the style of watch. There are a few different watch battery chemistries available today:
- Alkaline (labeled LR or AG). These batteries have a voltage of 1.5V, which tends to give them a capacity around 15-17mAh. The advantage of alkaline batteries is that they’re cheaper to make; the disadvantage is their voltage decreases over time. They have a shelf life of up to 5 years. However, their lifespan in a watch varies depending on how much voltage the watch uses.
- Silver Oxide (labeled SR, SW, or SG). With a voltage of 1.55V, this is the most common style of a watch battery. They’re cheap to make, like alkaline, but have a longer shelf life (up to 10 years) and a more constant voltage. Their capacity is higher, too, around 25-27mAh.
- Manganese-dioxide Lithium (labeled C or CR). A lithium battery has a voltage of 3V, with a high capacity of around 225mAh. These are the highest capacity option and are the best choice for more complex watch designs with high energy use. They have a similar 10-year shelf life to silver oxide but can provide more power during that span.
- Carbon–monofluoride Lithium (labeled B or BR). Very similar to manganese-dioxide lithium batteries in capacity and power, the main advantage of a carbon-monofluoride design is that it works better in extreme temperatures. They’re a great option for watches worn by hikers, campers, and others who spend a lot of time outdoors.
How can you tell which battery to put in your watch? The best option is to match your new battery as closely as possible to the one installed in it already. You can find that information etched into the top of the current battery.
How can I tell if it’s time to change my watch battery?
While the shelf life of watch batteries is long, they don’t last that long once they’re installed. Depending on the complexity, features, and design of your watch, you’ll likely need to change the battery every 2-4 years.
The most obvious clue that your watch battery needs to be changed is that the watch stops working. A dead battery is the most common reason a watch stops. Having said that, there are other signs the battery may be losing power, including:
- Not keeping the right time. Even if it hasn’t stopped entirely, if the watch runs too slow or too fast, the battery is probably dying.
- Jumping or frozen hands. This is a fairly common sign of a dying battery in older quartz watches. Most often, it’s the second hand that will give up first, while the others continue ticking along.
- Difficulty adjusting time or date. While this can be caused by worn gears or other mechanical issues, you should start by replacing the battery if the crown (the dial you turn to make adjustments) stops cooperating.
- Moisture inside the watch. In this case, the problem is the moisture, not the battery. It’s possible the battery still has years of usable life left. The problem is that moisture can cause corrosion, killing an otherwise functional battery. Replacing the battery will prevent leaks that could cause further damage to the watch itself. In this case, you should also take steps to dry out the other components—replacing the battery alone isn’t enough to fix the problem.
How to change a watch battery: Step by step
What you’ll need:
- Small knife, pliers, or screwdriver (depending on watch)
- Replacement watch battery
- Place the watch face down and examine the back. Most watches have one of three back cover styles: snap-on, screw-on, or secured with screws. Figure out which design you have. Those secured with screws are obvious (you’ll see the screws). A snap-on cover will have a lip where you can pry it off. A screw-on cover will usually have notches around the perimeter for the tool to grip.
- Remove the back cover. For a snap-on back (the most common style), use a slim, blunt knife or flat-head screwdriver to pry it off. A pair of pliers is usually effective in removing screw-on covers. If there are visible screws, you’ll need a small screwdriver, like those that come in eyeglass repair kits.
- Some watches have plastic protective layers under the cover. If this is the case, remove it carefully using a flat-head screwdriver or a pair of tweezers.
- Locate the battery, which should now be visible. Most are secured with two clips, one of which can be moved to release the battery. Gently pull this clip away using a pair of tweezers.
- Remove the old battery, insert the new one, and replace the protective layer and back cover.
What if I don’t have tools?
Most of the tools you’ll need to remove a watch back cover and replace a watch battery are things people have already in their home. However, not everybody has a tiny screwdriver or even a pair of pliers. While they’re fairly cheap to buy, you can get around this using other common household items.
If you don’t have pliers, you can use a pair of scissors to unscrew the back of a screw-on watch. Simply put the two sides of the scissors into grooves across the face from each other and turn gently. Be careful as you do this, to make sure you don’t slip and cut yourself.
No tiny screwdrivers? The tip of a pocket knife will often fit into one of the screw’s cross-hatches. Press it into the groove and turn slowly, to avoid having it slip out or strip the screw. This method takes longer than using a screwdriver, but you should be able to effectively remove the cover.
What’s the bottom line?
Changing a watch battery at home isn’t hard once you know what you’re looking for. The best advice is to wait until you’ve removed the cover to buy the battery. This way, you can make sure you’re buying the correct model for your watch. We hope this how-to guide has been helpful for you!