Portable Power

Solar power offers the possibility of keeping electronic devices running in the field on extended trips, and allows one to pack less batteries to power them. There are a few things to remember when using solar power to keep cameras, phones, tablets, and flashlights running, however.

Solar panels come in various sizes. The surface area of a panel determines how much power it can produce - this is measured in watts. A solar panel that produces 14 watts will charge batteries almost twice as fast as panel that produces 7 watts given the same solar conditions. Determining charging times of devices can be tricky, as power output is so dependent on solar conditions: panels produce less power on partially cloudy days, or when the sun sits lower in the sky. Keep in mind that optimal charge times assume optimal sun conditions: a summer sun, from late morning to mid afternoon.

Electronics such as modern smart phones and tablets are very picky about the voltage and amperage of the power they receive when charging. Fall above or below spec, and your phone or iPad will most likely produce an error message, and fail to charge. While many solar panels offer the ability to charge directly to a device, this is not always very practical depending on sunlight and conditions. On a clear blue sky day, solar panels can reliably charge devices. If however there is sporadic cloud cover, or you're charging at morning or dusk, power will fluctuate or drop, and devices will reject these variances. A better approach is to charge batteries with the solar panels, and then draw power from the batteries. Batteries (being "dumb" devices) will charge regardless of whether power is consistent or not - if power levels drop, the batteries will simply charge more slowly. By drawing power off batteries, the voltage and amperage remains steady, thereby delivering a stable power source to your device.