Hi guys, I was just trying to figure out how to create some basic graphs with GT view data. I created a graph of DC power to see if the modules were putting out thier rated power. I wasn't expecting to see thier rated 3010 watts, everyone tells you not to expect it. But due to them being rack mounted and with the fact that we rotate them in to the sun, we get near peak power most of the day. I am seeing DC side array outputs of 3100 watts or higher for periods up to 2 hours and max power of 3223 watts!!! These modules perform much better than I ever expected. I had noticed that the max AC output of the day was 3073 watts. So I figured that if output wattage reached higher than the Array rating, then the arrays must be overperforming thier rating. Another couple of nice features of these panels are thier low light sensitivity. It snowed for 2 days and the sun didn't shine at all, but the inverter still generated almost 3kwh for the day! It was pretty nasty out too. I also cant say enough about the Xantrex GT inverter. It looks like my average efficiency most of the day was around 94.5%. Outstanding. We have kept our old battery powered system connected. We isolate and run the house on it for several hours a day on sunny days just for the fun of watching the CMP power out meter spin 3 times faster than the power in meter ever does. I sure am glad I got a 3.3kw inverter rather than the 2.8 some say would have been sufficient. These things arent even that sensitive to shade. At one point we had half of 2 panels covered on 1 string and the array output only dropped to about 2800watts AC. With 2 panels shaded almost 100% the output was about 2500watts AC. Our days total Generation was 21.274Kwh!!! That doesn't mention the skystream also spun like hell all day. We pumped about 13.5Kwh back in to the grid overall durring the daylight hours. At least something we have is working right! Anyone else have results like these?

You have snow that reflects light and cold tempatures

Solar panels are rated at 25C and 1000wmsq so no surprise your getting above nameplate wattage, don't worry warmer tempatures are comming and you will get performance the rest of use get!

Sounds about right. On top of that, by keeping things unplugged or on a shut down power strip, we reduced our usage to 30 to 36 kwh per day compared to the 55kwh per day we had been using. On good days like yesterday we will generate 2/3 of our usage for the day. The windmill, had it been working properly, should have generated the other 10kwh over the day yesterday with winds between 15mph and 40 mph. But it seems like we got somewhere closer to 3kwh from it over the last 24 hours. My goal is to generate at least 50% of our yearly power with renewables, more if possible. It looks like we are getting there.

Also I should mention that you are right in your assertion of snow and cold Solar Guppy. Yesterday the temperature never got higher than 36deg F. The winds were blowing at around 10mph at ground level according to my Oregon Scientific WMR100 weather station. Also according to the weather station, the solar output yesterday was around 1200w/m2. So conditions were better here than STC.

i'm curious as to what weather station gave you a solar report.

Its an Oregon Scientific, it figures its solar output based on UV level I think. It seems to be fairly close, even though it looks like squares. The steps of the solar/uv graph mirror the graphs I made from the DC power output of the arrays. Its a calculation made within the Weather Display monitoring and datalogging software.

My setup is also Sunpower - 27 205BLK panels, installed in Nov 07. Despite my way less than optimum orientation, they are generating over 90% of max rated inverter output on warm days with regularity for sustained periods . And, the low light output is very impressive, too. On totally gray, overcast days, the system will generate 1,500W +, which is surprising.

On cooler days, I have been seeing 5050 - 5070W output, through a 5000W Sunpower rebranded GT-5.0. I never thought I would see that kind of output given my roof's angle to the sun but it has happened time and again over the last month - sometimes for sustained periods of over an hour. My yield for March was 772 kW-h which is about 100 more than I expected given the cloudy days. This month is looking good so far, maybe 800-820 if the weather holds.

I don't have any experience with other mfg panels but I am very satisfied with the way this system is working.

now, the installing dealer...that is a different story...

Our 3 Kw system is producing about 21kwh on most clear days and between 5 and 12 kwh on overcast days when you cant see the sun. Our average is about 15kwh a day, or about 100kwh a week for the month of March and it was only online for 3 weeks of the billing cycle. We used about 470 kwh net, compared to the 950 we were using after we installed the Windmill. We generate 326kwh in 3 weeks with just the solar. We are able to svae an additional amount by disconnecting the AC subpanel from the Main panel and running the whole house on the old Trace DR Inverter while the sun is out to keep the battery level up using the old 750 watt array. That way any power from the Grid Tie solar arrays or the Windmill will flow directly to the grid durring the sunlight hours, which we can later pull off from the grid.

Just FYI to all interested. Now that the days are getting longer, the temperature is going up and the snow is gone, our daily totals have dropped about 4kwh a day. We are now averaging about 17kwh a day on sunny days. It also seems that my fathers CB tower is more in the way than I thought. The smaller array has at least some shade until about 10:30 in the morning, which may stretch to 11:00am or later in June. I was thinking about digging up and moving the arrays, but I will probably give it a year before I seriously consider it. They arrays should have been on the opposite side of the tower, that way they would start to be shaded by the tower about the same time late in the afternoon as the neighbors trees begin to shade them. I figure this would only benifit us by about 2 or 3 extra KWH a day, but hey... every little bit helps.
Another possibility is to get a smaller grid tied inverter and some kind of dc transfer switch so that I could switch the old 750watt array of Siemens SP75s to grid tie every day once the batteries are full. I think thats a plausable cheaper, temporary fix until we can afford an XW inverter for the batteries and the old array. I figure that would save us an additional 3.5 to 5 kwh a day. Of course, I would need to find Grid Tie inverter that operates at 24v, reliably.... hmmmm. Wish batteries would last longer than 10 years, it would make an XW system more cost effective.