I ran across solar powered motion floodlights that use white LED lights to illuminate a pretty good swath of dark. Now keep in mind you don't get as much 'light' as you would with a wired halogen flood system, but, for the money and ease of installation you can't beat these. The company is called Silicon Solar
www.siliconsolar.com. Another cool feature of these models is that there is a small, red, LED that lights up at night...I think it's a status light. Anyway, the light make people think that there may be a CCTV camera up there. I positioned one light over each basement window and they work like a charm!