Got these after getting the 600w system with the movable panels that weren't able to be out in the rain. I wanted to just sit a couple out on the roof (not even bolted down) to start getting my feet wet into this solar stuff. Where I live is wooded, but I do have a little southern exposure & get about 4-6hrs of max charging time when the sun's out. The winter is to harsh here with the snow, so they will be mostly worthless in the winter, that's why I didn't bolt them down. gives me the flexablity to take them down if the winds are high & when the snow balls arrive. I may use the folding panels on decent sunny winter days. So, they charge well when It's full sun. I've seen 200wh once & 150-180wh. I can run a couple computers, wifi, TV, Stereo surround for like 11hrs when I'm getting some charging at the same time. Just running straight it's like 5hrs. This is why people have a roof full of panels, just two doesn't keep up or run that much with the system I got. Will most likely get more battery storage & Watts/hr at some point, put so far so good, I can run a few things, save a nickle maybe. Plus combines with a Propane heater backup I have, I may last for a day or so the next time the power is out & actually be somewhat comfortable now...