Introduction – Part 1

Going on a multi-week wilderness photography expedition in the wild with no place to recharge your batteries? In this blog series, we investigate solar charging your wilderness photography expedition.  In this Part 1, we test a solar charging system for keeping your camera batteries charged up and ready to go on your next long wilderness photo adventure.

Read below, or watch my 20 minute YouTube video.

Download Wildernes Expedition Solar Charging Calculator

Update:  Checkout my free Wilderness Expedition Solar Charging Calculator (Microsoft Excel).  Try it out and let me know what you think.

In this article, I’ll introduce the photography equipment I’m taking on a 3 week photography packrafting expedition to the arctic wilderness of northwestern Alaska, evaluate total daily energy consumption, test a 2 pound solar charging system under sunny and overcast conditions and find the break-even point where solar charging has weight advantage over just carrying lots of extra batteries.

Please feel free to drop any questions in the comments below. And be sure to subscribe to this blog so you don’t miss out on PART 2, results of a short 5-day field test packrafting in Oregon, and PART 3, the outcome of the 3 week trip to arctic Alaska.

First, a bit more about this Alaska trip:  It is a 3-week trip to packraft down the Kokolik River in north east Alaska in July.  We will have near 24 hour daylight, which is a contributing factor for considering solar power.

We will be covering hundreds of miles, mostly by floating on the river.  But there will also be significant backpacking.  Therefore, weight and compactness are considerations for my solar charging system.

Wilderness Photography Equipment

A critical first step in solar charging your wilderness photography expedition is understanding the total electrical energy your electronics will demand over the duration of your photo adventure.  We need to catalog all of the photography and non-photography electronics and information about their batteries.

My goals on the Alaska trip include capturing our adventure, arctic wildlife and the landscapes, in both still photos and video.  I’m expecting many hours of low-angle warm arctic light, and so plan to make lots of photographs and to shoot a lot of video.  I plan to share this experience with you here in future posts, so be sure to subscribe to this site now.

I will be using a Sony a6600 mirrorless camera as my primary still photo camera.  Its NP-FZ100 batteries each have a capacity of 2280 mAh, and I plan to drain one battery each day.  I will bring four batteries on the trip, along with a charger that can charge two batteries at a time.

A Sony RX100VA camera will be used for capturing B-roll video, and for shooting time-lapse footage.  Its NP-BX1 battery has a capacity of 1240 mAh, and I expect to exhaust up to two batteries each day.  I will bring four of these batteries on the trip, along with a charger that can charge two batteries at a time.

I will also have a Rylo360 camera for shooting 360 video while on the water in my packraft.  Its battery has a capacity of 830 mAh, and I plan to use up one battery each day.  I will bring two batteries.

Finally, there is my Samsung Galaxy 7 Edge smartphone, which I use mainly for GPS tracking.  In airplane mode, the phone’s 2800 mAh battery can typically last 3 days.  I’ll plan on 2 days just to be a bit conservative.  So that’s an average use of 1400 mAh/day.

Summing things up, I am looking at about 7000 mAh of energy use each day, and this is probably a very conservative number.  This is a key number we will use to size our solar charging system.

1 Electronic Devices
Wilderness Photography Equipment
Equipment for 3 Week Wilderness Photography Expedition

Wilderness Solar Charging System

Battery Banks

For additional energy storage, I’m bringing two Anker 10,000 mAh Powercore II battery banks with PowerIQ USB input and output ports.  I’ll explain why I’m bringing two of these instead of one 20,000 mAh battery bank a bit later.

This total capacity of 20,000 mAh battery storage gives me almost 3 full days of energy storage (20,000 mAh / 7000 mAh/day) for a total 17 oz of weight.

Solar Charger

To keep all this charged up over the 3 week duration of the trip, I selected the 14.7 oz. Anker PowerPort 21W solar charger.  This charger has two USB output ports with Anker’s PowerIQ charging circuits to match the battery bank inputs for faster charging.  Each output port is capable of delivering 2.4 amps individually, but they are limited to combined total of 3 amps.  Thus, the charger has a maximum useful output of 15W (3 amps X 5 volts).  So, with a 21W solar cell, I should expect the charger to output 15W even in less than ideal lighting conditions, which is something I will test.

This solar cell is no longer manufactured, so its availability is becoming limited.  There are other great alternatives available from RavPower, Nekteck and BigBlue, but I selected the Anker solar charger for its PowerIQ outputs, which are probably best matched to the PowerIQ charging inputs on my Anker battery banks.

Complete Solar Charging System for Wilderness Photography Expeditions

This charging system, including solar charger, two 10,000 mAh battery banks, two 3 foot USB cables and the two dual-battery chargers weighed just under 2 pounds.  If I only carried camera batteries on a 3 week trip, I would need 21 Sony NP-FZ100 batteries and 42 NP-BX1 batteries, which would weight about 6 pounds and cost about $1800.  So I am very happy with the overall weight and compactness of the system for wilderness travel on trips over 1.5 weeks.

Solar Charge System for Wilderness Travel
Solar Charge System for Wilderness Photography Expeditions

Wilderness Solar Charging Strategies

Here are the charging strategies I’m planning to maximize my solar energy capability.

  • Start with all batteries and battery banks fully charged before I leave home.
  • Smartphone will be in airplane mode at all times when out in the bush.
  • Both types of Sony batteries can be charged in-camera. However, I’m not going to plan on that, as it takes the cameras out of service.  I’d rather carry separate chargers to keep my cameras ready for use.  This is especially true for the Sony RX100 batteries since I plan to shoot time-lapse video with this camera even while I’m asleep.  The dual outputs on the solar charger, combined with bringing separate double-battery charges, also lets me simultaneously charge four batteries while I am out shooting from camp.
  • There are two ways to charge my devices. I could charge them directly from the solar charger, or I could charge them from the battery banks after charging the battery banks from the solar charger.  My strategy is to charge the electronic devices directly from the solar cell as first priority.  This is faster and more energy efficient than first charging battery banks.  Lithium-ion batteries have a charge/discharge cycle efficiency of around 80 to 90%.  By directly charging my batteries from the solar cell, I avoid a 10 to 20% loss by not going through the battery banks.  So the battery banks serve primarily as reserve energy storage in case the weather is not good for direct solar charging.
  • In sunny weather, I will always try to have two things charging from the solar charger in order to get the full 3 amps out of it, instead of just 2.4 amp when charging only one thing. This is one of the reasons I’m taking two 10,000 mAh battery banks instead of one 20,000 mAh battery bank.  There are 20,000 mAh battery banks with two charging inputs, but having two battery banks also gives me redundancy in case one gets damaged or fails.  And two 10,000 mAh units weigh the same as one 20,000 mAh unit.
  • In calm stretches of river, I may mount the solar cell on the bow of my packraft to collect energy while on the go. The solar cell is not rated as waterproof, but the river has long stretches of flat water near the end of the trip that should keep the solar charger dry enough.

Initial Backyard Solar Charging Tests

First I want to test the basics of charging my devices from battery banks.

Charging Devices from Battery Banks

Each device was discharged and then individually connected to the battery bank’s USB output port to measure energy transfer over a 1 hour period, and to then extrapolate an estimate for how much time it would take to charge full depleted batteries.

Results charging from the battery bank:

2 Charge from Battery Bank
solar charging your wilderness photography expedition: charging devices from a battery bank

Charging Devices from Solar Charger

Next, I tested solar charging on a sunny day.  Again, starting with depleted batteries, I connected each device to the solar cell, one device at a time, each for 1 hour to see how much charge was transferred.  Recall that the Anker PowerPort 21W solar charger has a maximum output from a single port of 2.4 amp X 5.0 volts = 12 watts.

For these tests, I’m using PowerJive USB ammeters to measure real-time electrical current transfer. This was also a great opportunity to weed through the big stack of USB cables that I have accumulated over the years, and find those that support the highest rate of power transfer.  I had purchased high-quality 3 foot long Anker USB cables, as my intent is to keep the devices being charged in the shade, while the solar cell is in the sun.  These cables also passed more current than any of my other USB cables, including the cables that originally came with the battery banks or solar charger.

3 Sunny Solar Charge of Single Devices
solar charging your wilderness photography expedition: charging devices from solar charger

Charging Multiple Devices from Solar Charger

Next I wanted to find combinations of equipment suitable for simultaneous solar charging to make use of as much of the solar charger’s dual-port 3 amp X 5.0 volts = 15 watts output as possible.

4 Sunny Solar Charge Two Power Banks
solar charging your wilderness photography expedition: solar charging multiple battery banks
5 Sunny Solar Charge Two Devices
solar charging your wilderness photography expedition: multi-device charging

By the way, not all solar charging systems are very tolerant of intermittent sunlight.  I tested for this by observing the solar cell charging my Rylo 360 camera at 0.65 amps under direct sunlight, then folded up the solar cell to see the current flow stop, then opened the cell back up again in the sunlight.  The charging circuitry recovered within a few seconds and resumed charging the battery banks again at 0.65 amps.  Not all solar charging systems will recover automatically like this, so this is important to test before relying on solar charging if there is risk of intermittent clouds or shadowing.

Solar Charging Devices on Cloudy Days

Finally, I wanted to see how the solar charging system worked under partly cloudy and cloudy days.

With 2 Anker 10,000 Powercore II battery banks attached, I found that the solar charging system produce from 0.46 to 0.85 amps, for an average of 0.7 amps.  This is about 30% of full sun charging current.  When charging 2 Sony NP-FZ100 batteries and 2 Sony NP-BX1 batteries, the solar cell produced from 0.59 to 0.75 amps, for average of 0.67 amps.  Again, this is about 30% of full sun charging current.

All of the tests above were conducted in April near Seattle, Washington, at an altitude of 250 feet, with maximum sun elevation of 50 degrees above the horizon.  I would expect improved performance during summer months (higher sun angle), at higher altitudes (stronger sun with less atmosphere) or in dryer locals (less light-scattering humidity).

Conclusions from Backyard Tests

I am expecting my wilderness expedition photography equipment, consisting of a Sony α6600 camera, Sony RX100VA camera, Rylo 360 camera and Samsung Galaxy S7 Edge smartphone to consume up to 7000 mAh of charge each day.

To sustain this equipment with the Anker PowerPort 21W solar charger, I will need about 4 hours of daily charge time in sunny conditions, or almost 14 hours of daily charge time in heavy overcast conditions.

Getting 14 hours of charge time each day could be a challenge.  But given that we will have nearly 24 hour daylight in the Alaskan arctic, I should be able to get at least 8 hours of charging in each day.

Considering that I will be carrying a total of 52,600 mAh in batteries, including the two 10,000 mAh battery banks, I will have enough energy capacity to operate for over 7 days, even without solar charging.

So if every day of the trip were overcast, and I was able to get in 8 hours of charging each day, I should have enough total energy capacity for over 17 days, which is just about how much time we expect to be in the wilderness on this trip.  With special effort in conserving battery capacity, I conclude the system is adequate for this trip.

One risk will be if we have many consecutive days of rain, where I will not want to expose the solar charger to the weather.  But under continuously rainy conditions, I will likely not be photographing as much, thus also reducing total demand for solar energy.

Testing the System in the Field

A field trial under real trip conditions is the ultimate test.

See Part 2 where I test the solar system in the field on a 5 day packrafting trip in Oregon.  Then watch for Part 3, where I then finally deploy the system on a three-week packrafting expedition in the Alaskan arctic.  Be sure to subscribe to my blog now so that you don’t miss out on these reports.

Below are affiliate links to the equipment used in this blog.  Using these links supports me with no additional cost to you.  Feel free to post any questions in the comments.  Thank you for your support!

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