The long-awaited Apple Watch is still a few months away and, without knowing all the official specs for all different variations, rumors about everything from software builds to battery life are starting to make their way across the internet. 9to5mac:
According to our sources, Apple opted to use a relatively powerful processor and high-quality screen for the Apple Watch, both of which contribute to significant power drain. Running a stripped-down version of iOS codenamed SkiHill, the Apple S1 chip inside the Apple Watch is surprisingly close in performance to the version of Apple's A5 processor found inside the current-generation iPod touch, while the Retina-class color display is capable of updating at a fluid 60 frames per second.
Apple initially wanted the Apple Watch battery to provide roughly one full day of usage, mixing a comparatively small amount of active use with a larger amount of passive use. As of 2014, Apple wanted the Watch to provide roughly 2.5 to 4 hours of active application use versus 19 hours of combined active/passive use, 3 days of pure standby time, or 4 days if left in a sleeping mode. Sources, however, say that Apple will only likely achieve approximately 2-3 days in either the standby or low-power modes…
Knowing how much battery life the Apple Watch has during testing is sort of like knowing a director wants Christian Bale cast in a lead role before production starts. It's super interesting if you love all the behind-the-scenes stories but ultimately what matters to you is how Michael Fassbender does in the movie you actually end up seeing — and how much battery life you get under typical conditions for the watch you end up wearing.
That Apple is including a powerful processor and high-density screen will be great for features as we're using them, less great for how long we'll be able to use them for. Everything is a tradeoff. Put in a really slow processor and a monochrome e-ink screen and it'll go for days... if you want to use it for that long.
For example the low-power, e-paper Pebble gets nearly 5-7 days of use off a single charge but doesn't offer anywhere nearly the same experience. Android Wear devices like the Moto 360, which have brilliant full-color screens, and robust notifications and apps, can make it about a day. It still comes down to how much you actually use your watch, however, and what you're doing with it. Like with your iPhone and iPad, the more you use it, the more you'll need to charge it.
So, if Apple hits the 19 hours of combined active/passive battery life they're reportedly targeting, where does that fit for you? Would you sacrifice power and display density for more? Would you want even higher performance for less?