You’re overcharging your smartwatch, and it’s aging the battery

Published Nov 7, 2026, 4:31 PM EST Ismar is a Senior Author at How-To Geek. He previously worked as a writer, editor, and general manager at a content agency before joining the team in 2023. He began his writing career in 2021 after completing a BA in English Language and Literature. Beyond How-To Geek, Ismar has contributed to Red Stag Fulfillment and Authority Hacker. He has also worked on various SEO projects to help clients improve their search visibility. Ismar has been around Windows PCs since the age of three, so friends and family naturally chose him as the resident tech support. His projects often involve tinkering, such as disassembling mechanical keyboards and gaming mice to mod his beloved gear. He also enjoys pushing hardware to the max through overclocking while staying on a reasonable budget. An avid gamer, Ismar has logged thousands of hours across various genres, including first-person shooters, RPGs, racing games, and roguelites. When he is not at his desk, he is probably exploring other people’s phones to discover their quirks and features or experimenting with the latest AI tools. In his free time, Ismar enjoys spending time with his wife, working out at the gym, playing guitar and bass, cooking gourmet meals, and traveling. Above all else, he’s a proud cat owner. After a long day, you probably plop your smartwatch onto its charging puck on your nightstand and leave it there overnight. Or, if you wear it to bed to track your sleep, you might leave it charging all afternoon after getting home so you can put it back on right before bedtime. Regardless of when you charge your watch, leaving it on the charger long after it reaches 100% is a habit worth breaking because it's destroying your battery. Keeping your smartwatch at 100% for hours every night accelerates battery aging A full battery isn't a happy battery Like the batteries in smartphones and other electronics, your smartwatch's lithium-ion battery gradually loses capacity over time. Some of this degradation happens simply as the battery ages, while some comes from charging and discharging cycles as you use the watch. Although you can't completely prevent battery aging, your charging habits can affect how quickly it happens. One of the worst things you can do to a lithium-ion battery is leave it completely empty or fully charged for prolonged periods. When a battery is left deeply discharged for too long, its voltage can drop below a safe threshold, potentially causing irreversible chemical degradation. This is fairly easy to avoid, though, as most people will instinctively put their smartwatch on a charging stand when its battery gets low to make sure it's ready for the next wear. The bigger concern with smartwatches is how easily you can end up leaving it at 100% for hours by accident. It's tempting to leave your watch on the charger long after it's full so it's ready to wear whenever you need it. Doing this once is fine, but repeatedly forcing the battery to be at 100% forces it to run at its maximum voltage puts additional stress on its components and accelerates chemical degradation. Your smartwatch has mechanisms that prevent it from overcharging, but you can't rely on them to eliminate battery aging. Some smartwatches also have optimized charging features that delay charging beyond 80% until closer to when you need the watch, reducing the time its battery spends fully charged. Still, when the watch sits on the charger for prolonged periods of time, it'll periodically top up its battery and constantly stay at an almost-full charge. So, if you want your smartwatch's battery (or any other lithium-ion battery) to last a long time, try to keep its charge between 20–80%, and only charge it to 100% if you know you'll need the extra juice. Your smartwatch doesn't need to charge overnight anymore Your watch can survive the night Back when smartwatches first became mainstream, many of the more powerful models had disappointing battery life. Many struggled to last a full day, especially if the display was frequently on and fitness-tracking features like heart-rate monitoring were constantly running in the background. That's why many of us who don't track sleep developed a habit of leaving our smartwatches charging overnight, sometimes even longer if we don't wear them around the house. However, this isn't the case anymore. Displays and processors have become more efficient, battery capacities have increased, and smartwatch brands have introduced various optimizations that extend battery life without sacrificing functionality. Most smartwatches on the market today can last you at least one full day of regular use, which may include sleep tracking. The Apple Watch Series 11 is rated for up to 24 hours, the Google Pixel Watch 5 can reach up to 40 hours with AOD enabled, and Samsung claims up to 30 hours with AOD on the Galaxy Watch9. This means an easy full day or two before you need to recharge. And since all three support fast charging, you have plenty of opportunities to top up the battery when you aren't wearing the watch. Leaving it on the charger for 15 minutes while taking a shower can add a useful amount of charge, although how much you get depends on the model and how much battery you've already used. I'm only scratching the surface of battery life here, though. Smartwatches that run proprietary operating systems instead of Wear OS or watchOS can last much longer than a couple of days. Many watches from brands like Garmin, Amazfit, and COROS can last several days, with some models lasting several weeks between charges. Replacing a smartwatch battery isn't nearly as simple as replacing a phone battery Smartwatches aren't designed to be opened The biggest problem with smartwatch batteries is that they're rather difficult to replace on many models. Manufacturers tightly seal their watches with gaskets and strong adhesives to keep dust and water out. The batteries are often glued in place, making them difficult to remove without damaging surrounding components. While some smartwatches are designed to be taken apart and have their batteries replaced, many aren't. Most mainstream smartwatches aren't particularly easy to disassemble, making battery replacements much more difficult (often harder than on a smartphone) and costly (often around $100). By the time the battery degrades, you might want to upgrade to a newer model anyway. You might even be tempted to upgrade your watch simply because its battery can no longer last an entire day. At the risk of going on a tangent, it's sad to see these gadgets treated as disposable. That's why the best thing you can do for your current smartwatch is to take good care of its battery, potentially allowing it to last through several smartphone upgrades before you eventually need a new one. Your smartwatch could last through several smartphone upgrades if you take care of the battery While there's nothing wrong with charging your smartwatch overnight every once in a while, turning it into a regular habit can be detrimental to its battery. If you want your smartwatch to last a very long time without needing a battery replacement, stop charging it all the way to 100%. Whether your smartwatch charges wirelessly using a proprietary puck or Qi, or uses one of those pogo-pin chargers, connecting and disconnecting it takes just a second, making shorter top-ups pretty convenient. Instead of charging overnight, just put your watch on the charger while you're at your desk, taking a shower, or getting ready to head out.