wongfeihong187 wrote:Thanks Neil. I'm using a single inverter (Sunnyboy 5000tl), but on two strands with 9 panels tied to each (total of 18 panels). Nope, it's sunny without a clouds in San Diego all weekend.
As noted in a couple of other posts, it's not the right time of year in San Diego for full production - the angle of the sun is too low. If you've got a good roof orientation your peak production will come in June/July/August. Another thing you'll notice, more during that time but even now, is that heat is an enemy - it increases resistance and lowers production. So you may find that on otherwise identical sun angle days, if the ambient air temperature is higher or there is less cooling from the wind, you'll produce less (than your rating, and/or compared to a cooler day).
As an example, my array is rated 3440w DC, which converts down to about 2960 AC. We have a 3000w inverter, which clips at 3060 watts, even if the panels are making more than that (which they do, on a perfect day (cool and with perpendicular sun angle). In the right conditions at the right time of year we'll make 3000+ watts at the peak of the daily production curve, but only for a fairly brief period.
Our peak production on a steady sunny day ranges from around 2200 at the winter solstice to consistently touching the max rating in/around June. On a more volatile day (intermittent clouds) at other times of the year it will spike up to the full rating now and then when the clouds cool the panels and then briefly move out of the way, but if it's a clear day the combination of low sun angle and heat will keep the max constrained throughout the day.