FlexSolar E10 Mini Review

The FlexSolar E10 Mini is a very small, light, durable, and surprisingly powerful mono-crystalline solar charger. At 7.3 ounces, it's the lightest portable solar panel we tested. It unfolds quickly and easily into a 19.2-inch long by 6.3-inch tall by 0.1-inch-thick four-panel array. Folded away, it measures 6.3 x 4.7 inches and is less than an inch thick. The simple and rugged design is ideal for backpacking or for anyone who needs a highly portable solar panel to bring with throughout daily life.

Direct Solar Charging Speed

The E10 Mini performed better than expected in direct solar charging speed tests. It is a 10-watt solar panel with a single USB-A output, capable of delivering a maximum of 2 amps. Panels with higher capacity (20W and up) often take higher scores here.

To test direct solar charging speed, we hooked up every solar panel to identical 10,000 mAh battery banks. Then we left each model in the sun in the same location to charge the batteries. Afterward, we discharged each battery using a digital USB multimeter, recording the mAh of charge that the panels generated during the hour-long test. We repeated three times, averaging the results of three subsequent tests.

On a sunny day at 8,300 feet in Utah, the E10 Mini generated 1,247 mAh of charge on its 10,000 mAh test battery. This output is slightly above average and better than most 5 to 10-watt solar panels.

Overall, the E10 Mini didn't perform better in direct solar charging speeds than most of the larger 20 to 30-watt panels we tested, but it performed about as well or better than every panel in the 10-watt range. It even outperformed a pair of 20 and 30-watt panels.

The E10 Mini's standout feature is not its solar charging capabilities; where this panel shines is its portability. Still, it performs better than we expected in direct solar charging speeds, for a panel of this capacity.

It has a total of four panels, creating enough surface area to generate energy from the sun. In our testing, it never actually produced 10 watts, but that is common with solar panels. Over the years of testing, we've found that most solar panels are rated for a wattage output that's only possible under the most ideal conditions, which we've yet to achieve. So, solar panels never put out the watts they're rated for.

Indirect Solar Charging Speed

The E10 Mini did not perform as well in our indirect solar charging tests as it did during direct solar charging. It saw a significant drop-off in power output under our simulated cloud cover, but it still generated some power. However, this is common with solar panels.

To test indirect solar charging speed, we did the same test as we used for testing direct solar charging speed, but covered every panel with a large white sheet. This sheet allows some light through, and simulates the conditions on a cloudy day.

On another sunny day in Utah at 8,300 feet, the E10 Mini, with the Big White Sheet suspended above, generated 235 mAh of charge on its 10,000 mAh test battery. This is significantly less than what it generated in direct sunlight, but it still created more power than roughly half of the solar panels in our testing lineup.

Portability

For a 10-watt panel, the E10 Mini is extremely portable. This is the lightest panel we tested, and folds away to a size that's smaller than many modern smartphones. It's small and light enough to fit in just about any pocket, and carry up any mountain, on the train, plane, or in your glovebox across town.

The E10 Mini uses a straightforward, minimalist folding design that allows you to set up and pack away quickly. There is no Velcro or any clips to catch on a pocket when you're packing it away, or get stuck when you're setting it up during your lunch break. It unfolds and folds up simply and easily.

The E10 Mini weighs 7.3 ounces, which is less than every other 10-watt solar panel, and worlds lighter than the 20-50 watt solar chargers we also tested.

While this model doesn't have a way secure it closed when folded, it never seems to unfold in a pocket. We packed and unpacked this panel repeatedly throughout testing and during a backpacking trip, and we never had an issue with it unfolding when we didn't want it to. We ultimately found the clips, snaps, and buckles on other panels were more of an annoying hindrance than a benefit. The E10 Mini was one of the easiest panels to use because it uses this simple, straightforward design. It sets up faster and easier, without every unfolding when we didn't want it to.

The solar charge controller and USB-A output doesn't have anything protecting it, but we never found this to be an issue. If you're carrying this in extremely dusty conditions, this could lead to the USB port failing. If you're traveling through a place with blowing dirt and dust, it's best to store this in a stuff sack or plastic bag to protect the USB port. That said, our testing locations were extremely dusty, and we didn't have any problems with the unprotected charge controller and USB output.

Functionality

The E10 Mini is hightly functional in a simple, bare bones way. It has a single USB-A output, carabiners to hang it off your pack or other object, and little else. It doesn't have many features, but we think this makes it more functional since there's less to get in the way.

The E10 Mini is really only capable of charging portable power banks. It will take several hours to charge a 10,000 mAh battery pack fully with this panel, but it will eventually charge. It doesn't create enough charge to power higher-watt devices, and the variable current produced by a small solar panel isn't ideal for directly charging a smartphone. This is common with solar panels, but is particularly an issue with lower-watt panels.

The E10 Mini has carabiner loops to hang it while charging. It doesn't have kickstand legs to angle it at the sun, but it's light enough to make it easy to prop it up at any angle on almost anything.

Should You Buy the FlexSolar E10 Mini?

The E10 Mini is a stellar option for an ultralight solar panel for backpacking. It is extremely lightweight and packs into a small package quickly and easily. It's not the most powerful panel, but if you're looking for a panel that proiritizes weight and packability over massive wattage, this definitely a good model to consider.

What Other Portable Solar Chargers Should You Consider?