Whitebalance.space/Getty Images Some smartwatches only last a day before they need to be recharged. But there are many smartwatches that last for days, even weeks per charge. Some can last virtually an infinite amount of time, at least months, with constant exposure to sunlight or a strong light source via solar power. But with any smartwatch, even the ones that last longer than others with typical use, there’s one feature that drains battery life very quickly: built-in GPS. Using this fea...