Hi! I was wondering if solar power is efficient for lights. That means I want to have free electricity for at least 10 years (before they break and I have to buy another set of solar cells). First of all, I know this shit isn't inexpensive. But anyway! How much for solar cells that would be able to produce app. 1 kW per hour? Are there any good combined capacitors/batteries that can be charged via cells and via standard household electrical supply? Just in case I want to have a standard backup if solar cells give up for a day or two. Basically I want this: solar cells with output of 1 kW per hour (it MUST withstand the longest cycle for growing under HPS/MH); a battery that can be simultaneously charged via solar cells and ordinary electricity from the household. How many square meters/feet of solar cells do I need for that kind of an output? Let's say this is for two 400W HPS lights.