Holy Cheap Solar Panels Batman | Alternative Energy | Forums

100 watts

lets use a simple 60 watt light bulb as a example. that light bulb will use 60 watts in one hour, that's why it's called a watt/hour. Say you have the light on for 5 hours, you used 300 watt/hours. So you have a 100 watt panel, average sunlight here in NE is 5 hours a day. So technically you generate 500 watts of power in a ideal world. Unfortunately we don't live in a ideal world. Each panel has a efficiency rating, usually the higher cost of the panel you get the more efficient you get, but let's say we have 90% efficiency. That means you would actually generate 450 watts of power, so you could technically run the light for 7.5 hours. Not so fast, you need a inverter for that, they also have efficiency ratings, when you run 12v thru a inverter you lose energy through transfer in the form of heat, so lets say your inverter has a 90% efficiency rating that would bring your 450 watts down to 405 watts of power and that brings you down to 6.5 hours or so. It can get very technical but that is the simplest way I can explain it. You need to figure out your usage and build your system up to that. That's why it's usually cheaper to downsize your load and usage (smaller tv, fridge, etc) it will decrease the size and the cost of the system you need.