XO Solar/GPSolar

These a 10W panels for $50. Not yet in stock in the US, they had to special order them from Hong Kong in January, just arrived today to my home in Austin on March 20.

I will be reporting on how it goes.

16:40 update

Have had an XO charging for 3:30 h now, from flat - no response state. Not an ideal angle for the panel, but nevertheless I expected some more than 52% battery. Same placement than the May 28 test, so, yes, the sun is lower in the horizon in March.

Just arrived

they're 16" x 22" (40 cm x 55 cm)

They have an XO-capable plug already. The photo shows the data sticker on the back

The solar panels are embedded in a fiberglass-looking support, mounting holes in the corners, some sort of a regulator in a box on top