With the many features packed into the Apple Watch, it needs a battery that's up to the task of supporting those functions over the long haul. That's what Apple delivered with its latest lineup of smartwatches. The newest Apple Watches can run for 18 to 42 hours between charges if you include sleep time, so you can make the most out of them. But no matter how long-lasting the Apple Watch's battery usually is, it's bound to run out of charge sooner or later, and maybe sometimes when it's most inconvenient for you. If you need to squeeze more runtime out of the smartwatch, there are a few nifty tips and tricks you can do to improve the Apple Watch's battery life — one of which involves a yellow circle in your status bar. This yellow circle on your Apple Watch just means that Low Power Mode is activated. It's essentially the equivalent of your iPhone's battery icon turning yellow.…