Apple Watch is supposed to have 18 hours of battery life, which would translate into a full day if I were to ever keep to a normal sleeping schedule.
I was able to lengthen the uptime of my watch to a full 24 hours on days in which I didn't make battery-taxing phone calls with it, or use the half-as-power-hungry heart rate monitor.
I'll put it simply: I think Apple deliberately downplayed the battery life of its Watch to make sure it didn't get hit with angry users should the numbers not stack up. I've had days where I've been for a couple of hours' run and it's still easily lasted the day, and not once in the week of testing did I get to the evening approaching critical levels of power.
Apple Watch depletes the battery in three hours if used for non-stop phone calls. Working out with the heart rate monitor or listening to music does the same in six hours. Conversely, just checking the time every so often boosts it to 48 hours.
But you'll also need to think about the future here. Like Nokia's old attempts at smartphones, the battery life on the Watch is good because you don't find yourself wanting to play with it a lot because, well, it doesn't do a whole lot right now.
That's going to change though. As developers get their hands on the Watch and start making use of the inbuilt NFC or other sensors, you'll find the battery life will drop faster as more apps start making a play for its reserves.
Talking of which, a 72-hour Power Reserve mode kicks in when the Apple Watch battery reaches 0% so that it doesn't shut off completely. It only tells the time doesn't keep the fancy watch face.
This sent me running to a charger since it does nothing else in this catatonic state. Making it even more perilous, it was actually a bit difficult to exit this catatonic state. The watch takes a solid minute and a half to reboot, which initially made me think I didn't know how to reboot the device and was accidentally resetting it every time.
Power Reserve mode
The official Apple Watch recharge time is 1.5 hours to 80% and and 2.5 hours to 100%. That's a bit slower than the average smartwatch. Moto 360 charges up in 2 hours flat. But I've been able to completely recharge my Apple Watch in the same 2-hour window.
The 205mAh battery pack is predictably sealed into the device, and is smaller than the battery on other Android Wear devices.
My faster-than-expected charging time may be because, at 0%, the watch still has its limited time-checking Power Reserve state to go. I had charged the watch when it and entered this special mode, so it technically had some juice left to it.
Apple Watch's inductive magnetic charger takes cues from the company's popular MagSafe chargers, which come with all MacBook Air and MacBook Pro computers (but not the New Macbook).
It combines a MagSafe magnet with an inductive charger for a wire-free solution. It helps when you're in the dark or in tight situations, like a coach seat on an airplane, and need to simply clip on a charger and be done with it. Magnets, boss.
As much as I don't like having yet another type of cable to carry around, it's way better than the flimsy Pogo charger designs used by Pebble, LG, Samsung and others. It wire-free design also means that Apple Watch is sealed and is therefore water-resistant to a point.
The watchOS 2 upgrade brought with it nightstand mode, which is pretty cool if you're after a mini alarm clock. The display will even start to brighten up as your alarm appears, which is another neat touch that Apple's added in.
It doesn't stay on all night though - and you can even turn off the mode in the Watch app too. It's a nice idea and great if you've bought a stand like the Griffin WatchStand (although this does look a little like a dragon's genitalia when sat on your nightstand without the Watch on).
There's also the official Apple Watch charging dock, but as with anything made by Apple, it's more expensive for what it's worth. The included charger or a third-party option will do most people justice.