Extending the battery life of a smartwatch is pretty easy.
Smartwatches— they're the next evolution in horology. First, it was the Quartz revolution of the 80s and 90s which brought the cost of watches down not only for the manufacturer but it also the consumer, all while being more accurate than an automatic watch like a Rolex or comparable more expensive watch. The Quartz watches annoyed purists because of the "jittering" of the second hand, but at least these could last decades before needing a new battery. Now, watches are changing again, and we have to charge them once a day just like our phones.
While charging a smartwatch isn't a big deal because they do charge very quicklyt—the Apple Watch Series 1 charges from around 10 percent (which is when power saving mode prompts) to a full charge in about an hour on the charging puck—the battery life is still far from ideal. This is especially true if you're smaller wristed and have to go with the 38mm as you're limited to 18 or so hours of charge before you inevitably have to put it back on to charge.
Still, there are certainly ways to improve your battery life, such as turning off notifications from most apps, but that seriously defeats the purpose of having a smartwatch in the first place, since most who own them are using them as a discreet way of checking their social media notifications and texts along with being able to text without taking your phone out of your pocket. The fact you can also check the time like a traditional wristwatch is just gravy on top of the fitness tracking and being able to add something fashionable to any outfit as straps can be changed in seconds.
Aside from that, turning off the GPS, sound, and other wireless connections that are non-essential will reduce the strain on the battery. Turning off the LTE on the most recent generation of Apple Watches is also a good idea.
There are also some more obvious no-brainers as well. These include shutting down apps that run in the background and turning the brightness down. Which kind of sucks since it's very hard to read the Apple Watch (in our experience) unless the brightness is cranked. Basically, think of your smartwatch like your smartphone. If one thing will save the battery on your phone, it will save the battery on your watch as well. One should also probably contact tech support from the manufacturer of the smartwatch if they've owned the device for a while as continuous use and age will wear the battery right down and make them almost unusable — though, often times they will be a little worn out and not as efficient as they used to be. Turning off other hardware settings that may drain the battery will also help.
There are a few ways that Apple and other smartwatch makers could improve the battery life too. To be fair, they have already done this to a degree with the newest generations of watches getting up to 20 hours. Still not great. It obviously never will be able to get up to the crazy length of time of say a Quartz watch, but it could certainly be improved by various means. While not the most fashionable, they could look to the Breitling Exospace B55 connected watch for inspiration as just one way to improve the battery life, it integrates smart technology into a traditional watch, this would be something that a lot of Android smartwatch makers would find of interest. Though that's because they use a round shape, which is easier to develop a battery for without making it too thick (and a lot of smartwatches are bulky, though that might be more from what's popular right now). Apple, on the other hand, went for a square-ish shape which allows them to develop technology more easily, which is impressive with how thin their product is already. Though this thinness is part of why the Apple Watch has mediocre-at-best battery performance. On a day of heavy usage, you're lucky to get 10 hours.
This thinness may work in the Apple Watches favor by adopting a technology used in Citizen watches called Eco-Drive. Watches that use this are some of the most interesting pieces of horological technology out there by using a special cell to convert either sunlight or artificial light into energy. These silicon chips are the size of a micron, so it isn't like these devices would need to become bigger to utilize them. It would just be a matter of big-name companies contacting Citizen and working out a business relationship to utilize them. With this, watches could go longer between charges.
But that's OK, smartwatches are at their infancy stages right now — they aren't a matured technology like their older automatic and Quartz brothers. So, manufacturers can experiment all they want right now as there are no established expectations other than them working the way they should.
We're at a point in time where this type of watch is going to slowly be adopted by the masses and that will lead to new types of smartwatches in the future, maybe we'll even see ones with diving bezels in the future. There are a lot of smartwatch makers can learn from their mechanical counterparts.