UPDATE Apr 2020: I’ve since purchased a second unit and I recently had the opportunity to test my two units while “boondocking” (RV term for remote camping). I wired them in series and hooked them up to a Renogy 30 amp MPPT charge controller.

The best output I saw from the two panels (all numbers according to the Renogy controller) was 186 watts. During peak sun the output more typically hovered around 170 watts +/- 5 watts. During the three days we used the panels we got right around 1.5 kWh per day. This was in early April at 37°01’10.5″N latitude.

I used cheap aluminum music stands to prop up the panels (2 stands per panel) and pointed the panels at the sun, rotating them occasionally to follow the sun’s track throughout the day.

186 watts from the two panels is remarkable (93 watts each); probably a little too remarkable for two nominally 100-watt panels. I’m guessing that Rockpals derates the advertised capacity from their nominal capacity. Indeed, there is another seller of what appear to be (almost) identical panels that advertises its product as 120 watt panels.

Original review:

This panel is very nicely portable; the fact that it folds in fourths rather than half makes the form factor much nicer for transportation. The inclusion of various DC barrel connector sizes is nice.

At local noon on May 13 at 40.29 degrees north latitude this panel put out 73 watts according to the portable power bank it was charging. DC amps were measured at 5.6 using a clamp-on ammeter. Open circuit voltage was 19.2; didn’t have a convenient way to measure voltage under load (but if you believe the watts reported by the power bank then the voltage was right about 13). (Note: the photo is of a previous day in the late afternoon.)

I used it to charge the 400 watt-hour power bank in the photo. The bank was between 20% and 40% charged (the bank display only 5 levels: 0-20, 20-40, etc.) and reached 100% charge in about 5 hours with charging starting at 9:45 am daylight saving time.

About the only negative I’ve found so far is the lack of any sort of included or attached prop-up device to place the the panels at an angle.