Technology on the Trail: Part 1: Devices and Power
Wednesday, November 9, 2016 2:11 pm

When I decided to hike the Appalachian Trail, one of the choices I was faced with was what electronic devices I should take with me. The more I took, the more weight I would have to carry, and the more dependent I’d be on power outlets. As much “fun” as it might have been to have my laptop — which would have made writing blog posts way faster — it would have been entirely impractical weight-wise. After not really much deliberation, decided on five pieces of tech: my phone, my watch, a headlamp, a battery (and power adaptor), and a solar charger (and the necessary cables to connect everything).

Headlamp

The only strict electronic necessity I took on the trail was a 120 lumen headlamp with a USB-rechargable battery. Being rechargeable, I didn't need to buy (or carry!) batteries, and could charge it either from the wall, or my battery, if necessary. The headlamp claimed to have a maximum 90-hour runtime, which I never came close to using. While I could easily have charged the headlamp on the trail from my battery if needed, in practice, I used it so little that I only needed to charge it up about once a month when in town. The headlamp worked quite well; I had no complaints.

Because I preferred to arrive at wherever I was stopping sufficiently before sunset to set up camp and cook dinner, the headlamp generally got used only a few minutes each night during bathroom breaks. If I got into camp late, it might have gotten used for at most an hour to provide light while setting up camp and cooking. Only one night did I need it for hiking after dark, and even that night, it was on for less than two hours.

Phone and Watch

Taking my iPhone 6s was an obvious choice. I wasn’t expecting to have a constant signal, but I did expect to have signal at least every few days on the trail, and whenever I was actually in town. Besides an emergency communications device, I needed it to update my blog, and make gps tracks of my hike.

My Apple Watch was a less obvious choice (and the one my fellow hikers asked the most about). I wanted it along for the activity tracking (knowing full well it was going to be inaccurate simply because it wouldn’t be able to take into account altitude change or the weight of my pack), but it turned out to be far more useful than I had initially anticipated.

More on both the phone and watch in a later post.

Power

Central to making effective use of any technology I’d take was making sure it would stay charged. To that end, after some research, I opted for a two-prong approach: battery, with solar backup.

To determine how much battery I'd need, I needed to determine what the worst-case was for time outside of town. As it turns out, the longest distance on the trail between trail towns is at the (north) end of the trail: it is roughly 115 miles between Monson, ME and Katahdin, including the Hundred Mile Wilderness.

It's advised (rather strongly, on signs at both ends of the Wilderness) to carry ten days of supplies through the Wilderness, and while the Wilderness has a reputation for difficulty, ten days (plus another day to summit Katahdin) represents a rather slow and leisurely pace. But we're looking at worst-case, so, ten days was a good starting point.

An iPhone 6s has a 1715 mAh battery; the Apple Watch a 246 mAh battery. If I drained both completely each day, that would be 19610 mAh I'd need from a battery.

My primary source of power on the trail was a RAVPower 20100 mAh portable charger, conveniently having the ten day capacity I was looking for. After looking around at various batteries, I selected this one for its high power capacity and because it had the highest energy-to-weight ratio. (It wasn't the largest battery available; I had considered a 26800 mAh version, but it had a lower energy density, and the extra three or four days of power it would provide didn’t seem worth the extra weight.)

Coupled with it was a RAVPower 30W wall charger. 30W was probably overkill, but between that and the “QuickCharge” technology shared between the adaptor and the battery (which was supposed to improve charging efficiency and speed), I felt it was a good combination. The idea was to make sure that the battery and my phone and watch could charge as fast as possible assuming limited availability of power.

In addition to its power input, the battery had two useful USB ports (as well as a USB Type-C port that was all but useless for me). The wall charger also had two USB ports. When in town, this allowed me to always charge the battery and one other device from the wall. If I needed to charge two (or three), I could always plug those devices into the battery, though I preferred not to do that unless necessary, so as to reduce the number of charge cycles used on the battery.

When I was planning, I was concerned that I wouldn’t have much time in town to actually charge anything: I was expecting I’d be charging when I visited grocery stores or restaurants, so, only an hour or two of charging time each week. I didn't fully appreciate at the time that the Appalachian Trail is not really all that remote, and that hostels and hotels were readily available.

The longest I ever went without being able to fully charge the battery was eight days (and it got about 20 or 30 minutes of charge somewhere in the middle of that), and despite probably coming pretty close to empty, I never ran out of power, despite using my phone a whole lot more than I anticipated.

I never quite figured out how long it took to fully charge the battery. For a full charge, several hours, at least. Except for the one partial charge, I usually plugged the battery in and let it sit, either overnight or for most of an evening, and it was fully charged by the time I checked on it.

Solar: more useful for suntans than power

While I was reasonably sure I wouldn't run out of battery power, I also bought a PowerFilm USB+AA Solar Charger as a backup power source.

I didn't have particularly high hopes for solar charging: the Appalachian Trail is well-known for its “green tunnel”. Most of the trail is under leaf cover by mid-April, but this solar charger came recommended as being very good in indirect light. I wasn't expecting much; still, if a solar charger provided even only enough power to charge my watch daily, that’d provide an extra day or two of power for my iPhone, should the need arise. Solar power would just be extra cushion.

Unfortunately, my solar charger was an immediate disappointment. While it seemed to be charging its own batteries, it failed to charge either my phone or my watch, and so wound up being dead weight for the first week of my hike, until I sent it back home when I arrived in Hiawassee, GA. Likely, the unit I got was defective somehow.

As it turned out, with as often as I stayed in town, a solar charger was entirely unnecessary. By the time I got to Hiawassee, it was clear that my watch and phone were using less power than I had originally expected, so by then, I was not especially worried about running out of power.

Technology on the Trail series

This post is part of my “Technology on the Trail” series: