Changes

The Epix's standard battery life is not enough for longer ultramarathons; most runners in a 100-mile race will need a little longer at least. One option is to reduce the GPS polling interval, which bumps the battery life up to 50-hours, but you could also [[Charge On The Run| consider charging the Epix during your run]]. The Epix has about a 350 500 mAh (milliamp-hour) battery based on my measurements, so it doesn't take much to recharge it. In fact, the problem is generally finding a battery pack that's small enough, as batteries tend to be heavy. My two preferred options are below, the Anker and the PulsePak.

The Anker is much bigger (3.75"/9.5cm) and heavier (2.9oz/82g), though it's shape makes it easy to carry in your hand and it will slip into the pockets of Race Ready shorts. It holds 3,350 mAh, which is way more than you need, recharging the Epix more than six times over ten times. It's reasonably priced at <jfs id="B005X1Y7I2" noreferb="true"/>. The PulsePak is far smaller (2"/5cm), lighter (0.5oz/15g), and cheaper at <jfs id="B00WBIK25C" noreferb="true"/>. It only holds 500 mAh, but that's enough for a full charge, and it's small enough to carry a couple. The obvious approach is to use the charging dock and cable that came with the Epix, holding a battery pack in your hand, which is shown below. I'm not a fan of this approach as the battery occupies your hand and the cable is rather long. You can tuck the battery in a pocket, but then the cable really annoys me. (Putting the watch and battery in a pack or pocket seems to defeat the object of having a watch if you can't see it.) The Garmin Epix has its charging port on the side, and the cable just clips in. You can see the standard cable below, along with an aftermarket adapter. (The yellow cable tie is just a marker so that I can find where the watch is plugged in when I've got lots of them on charge at the same time.)