Features | Hardware
Most watches run on rechargeable lithium-ion batteries and hold enough power to last for up to 8 hours per charge in exercise mode. This means that, in theory, you can work out with the watch for 8 hours before it needs to be recharged. Although true battery life will vary. Factors like how it’s used (the backlight significantly drains the battery), storage temperature and humidity (leaving it in a hot car = not a good idea), and the overall age of the battery influence how long a battery lasts per charge.
While 8 hours of juice is common for most watches, there are some exceptions. The Garmin Forerunner 10, while a great budget watch, only has a 5 hour battery life. But the Garmin Forerunner 310xt and 910xt have a battery life of more than 20 hours.
Waterproof vs. Water-resistant
Every watch is sweat and rain-proof. A must given their intended use. But only half of the watches made today are waterproof enough to swim. As we discussed earlier, GPS watches lose satellite signal under more than a few inches of water. For most purposes, a waterproof GPS watch used when swimming is really only as good as a stopwatch. If you swim outside, the bathing cap method (sticking the watch in your cap) will stay above water enough to maintain a GPS signal. But you lose the ability to view the watch while swimming. A few models (Garmin Forerunner 910xt and Tom Tom Multisport) that we’ll discuss below use accelerometers to bridge this gap.
When looking at a watch’s waterproof ability, make sure it clearly states water-resistant to at least 30 meters. A few watches are water-resistant to IPXC7 standards; this confusing piece of terminology just means that the watch can be immersed in water and survive, but it can’t be submerged for long periods of time. In other words, don’t take it swimming.
Most watches have the GPS sensor built into the watch itself. This adds some bulk and weight but has the benefit of being a single unit. A few Polar models, as well as the Bia Sport Watch, have a GPS unit separate from the watch. While this has battery-life benefits and shrinks the size and weight of the watch, the GPS unit becomes a second piece of equipment you need to carry with you and remember to charge.
This feature isn’t very common and for good reason: most watches do just fine with a few buttons. A touchscreen is more of a gimmick in that it seems kind of cool but doesn’t add a lot of value. In fact, as Garmin found out when it released the Forerunner 405, the first GPS touchscreen watch, it can be disastrous. The touchscreen on the 405 was insanely sensitive, and was often inadvertently activated by drops of sweat or rain. Luckily, Garmin solved this issue with the Forerunner 610. Though discontinued, the Forerunner 405 and 410 can still be purchased, so keep this defect in mind if considering one.