That solar panel on the top seems awfully small to me. If you look at the solar panel on the helicopter that's already on mars, its almost 3 times bigger than the body. This just looks tiny in comparison.
It's hard to get a good sense of scale from the image, but the solar panel on the concept is about 0.5m in diameter. JPL has run the numbers as part of their engineering study, and MSH would be able to recharge itself in a day.