San Francisco's climate isn't exactly "ideal" for solar-powered gadgets, in that the appearance of the sun is a rare and fleeting occasion. But the output and sound clarity you get from the Eton Soulra XL boombox are surprisingly decent.
Battery life: 4-5 hours
Charge time: 5 hours (direct sun)
Drivers: 2 tweeters, 4 passive radiators and 2 woofers
Dimensions: 8.125" H x 15.125" W x 5.25" D
You don't have to worry about finding an outlet or putting down a 10-spot for 40 minutes worth of D-cells, since it thing charges as you use it with a gigantor 465sqm solar panel. The panel swivels, so you don't have to re-position the entire box just to keep it in direct light. It's loud and clear for being a mere 22W portable system. The rubberised exterior makes it water-resistant, so it's safe (enough) to keep poolside.
The Soulra XL is hefty at 3kg. In direct sunlight, it charges in about five ungodly long hours. Or, if you're in a hurry, it also charges via DC input in about 90 minutes though that rather defeats the purpose. And those five hours may be a fair trade-off compared to my old boombox's crippling D-battery addiction but it's still a long-ass time to wait for your tunes. The anti-glare cover is a great idea, but requires keeping the screen's backlight to actually see anything it's displaying.