Results from 100 hours of field testing 15 portable solar panels - By Reddit Users

Generating power without the grid is important, so many preppers carry a solar charger in their go-bags. But we found most online reviews in this category to be flawed (such as not measuring sunlight for fair comparisons).

So we bought proper testing equipment and spent over 100 hours getting our science on.

This is our first version of these tests. As always, happy to hear any feedback and answer questions!

The contenders: https://imgur.com/n1AICuz

The test setup: https://imgur.com/eIAHWJw

Example test chart: https://imgur.com/hOxYzq0

For the full charts, review notes, and tips, see the review of the best portable solar chargers for your backpack or car kit. If you want a simple-terms primer, there's a link in there to a beginner's guide to off-grid power with photos of different gear mixes and what they can charge.

The winners:

Best overall: Ryno Tuff 21W

Best compact: Renogy 10W

Best large: BigBlue 3 28W

Summary:

We ran tests that measured sunlight and power output every 10 seconds, used a FLIR camera to check panel heat, and reconciled everything against official weather data from a nearby airport.

We found big differences between products and it wasn't clearly correlated with price or brand.

In fact, the ubiquitous Goal Zero products failed pretty hard, especially when considering they're 2-3X the price of the competition.

Angle to the sun matters more than just about anything, as you can see in the orientation test results. You can get almost full power at 7 PM if angled right vs. almost no power if you hang the panel off your backpack at Noon.

Panel size is another core factor. A cheaper big panel generally did better than a premium smaller panel — especially in constant low-light conditions.

Don't plug your phone / devices with built-in batteries directly in the panel while baking in the sun. Try to power a separate battery pack that you then use to charge your devices.

Similarly, prefer chargers without a built-in battery, rather than the combo units.

-user the_prepared