Backcountry Strategy for Charging Your Phone and Other Devices

It’s a modern reality that most of us take our phone and other electronic devices into the backcountry.  Therefore you will likely need a plan to charge your phone and other devices. When we’re at home, it’s no big deal to charge up your phone or smartwatch every night. But when you’re off the grid you need a plan to charge your phone on a hiking trip, bike packing trip, or backcountry rafting trip. This blog post will help you develop a strategy to keep your devices powered up on your adventure. We also provide some tips on optimal solar panel usage if you decide to use a solar panel.

Related: Choosing the Right Charger for Your Thru-Hike

We purchased all items in this post and are not paid to mention any product.

A phone plugged into a solar charger while a hiker is resting

Total Up All Your Power Needs

Below you will see a list of the electronic gear I took on my John Muir Trail hike. I also included the battery size in mAh (milliamp hours) and the approximate daily power I consumed. Your power consumption will vary based on your needs.

— iPhone 12 Mini Smartphone: 2,227mAh battery, used about 1,200 mAh a day, depleted at the end of day 2

inReach Mini Messenger: 1,250 mAh battery, used about 200 mAh a day, depleted at the start of day 7

Petzl CORE Headlamp Rechargeable Battery: 1,250 mAh battery, used about 100 mAh a day, depleted on day 13

On most days, I used about 1,200 to 1,500 mAh.

I carried a 10,000 mAh external battery pack to recharge the above devices. I also used a solar panel to recharge the battery pack.

Determine Your Charging Strategy

All of my electronics were fully charged on day 1. The iPhone ran out of power at the end of the second day. The inReach Mini messenger did not need to be charged until day 7 of the hike. And the Petzl CORE rechargeable battery did not need to be recharged until day 13. This means that I mainly used my 10,000 mAh external battery to keep my iPhone charged. I used my to take a GPS recording of my hike and to take photos.

Assuming I only used the external battery to charge my phone, I would expect the external battery will be depleted on day 6 (6,500 mAh (see note) battery pack / 1,200 mAh usage by the iPhone = 5.4 days). This is exactly what I observed on my John Muir Trail hike.

*NOTE: We can assume the external battery will provide only 65% of the listed power due to loss of energy during the transfer process.

Most long-distance adventurers resupply every 4 to 5 day and have access to a wall charger to re-charge their external battery pack. So a 10,000 mAh external battery bank is sufficient for their power needs. But on the John Muir Trail hike we were hiking about 10 days between resupply points, so we needed more power than a 10,000 mAh battery pack could supply.

We had two choices: we could carry a 20,000 mAh external battery pack (or two 10,000 mAh batteries), or we could carry a solar charger to re-charge the battery pack. Due to some advances in solar technology and the fact that we were going in and out of resupply points too quickly to wait for our external battery pack to charge, we decided to try out the solar panel.

If you are not carrying a solar panel, just remember that you will need several hours to re-charge your external battery when you do find a wall plug.

Related: Should You Carry a Solar Panel on Your Backpacking Trip?

Tips on Optimal Solar Charger Usage

Chart of Solar panel charging current versus time of day

The Optimal Time of Day to Charge with a Solar Panel

On my John Muir Trail hike, I found that the best time to charge up my external battery pack using a solar panel was in the middle of the day when the sun was more direct. In the morning and evening hours the sun intensity was low and the charging rate was minimal. As you might expect, as the day progresses sun intensity increases, and between about 11 AM and 4 PM the charging rate is highest. Optimal timing will depend, of course, on the season and where you are located.

I like to take my longest break in the middle of the day so I can get out of the sun. This is a great time to position a solar panel in the sun for optimal performance. I keep my solar panel attached to my pack with a piece of paracord so that I don’t accidentally leave the panel behind.

Chart of the impact of shadow on charging current

Keep the Solar Panel Out of Shadows

I measured how the solar panel charging rate was affected when it sat partially in a shadow and the results were dramatic. A shadow covering only 25% of the solar panel dropped the charge rate by about 50%. It is very important to keep your solar panel out of the shade for optimal performance.

Keep External Battery Away From Direct Sunlight

When you are charging up your external battery with a solar charger, it is very important to keep the battery away from direct sunlight. If the external battery pack heats up it will not charge as fast. Extreme temperatures can actually permanently damage the battery. I keep my external battery inside my pack while it is being charged by a solar charger.

Keep Your Solar Panel Clean

And finally, it is important to keep your solar panel clean of dirt and debris. Accumulated dirt blocks the sun and will drastically reduce the efficiency of your solar panel.