Lots of Watts

Yesterday was so clear and cool that I think the charts from my house might represent an ideal system maximum for March 17th at this location. March 16th, the day before yesterday, was almost identical.

This chart reveals that night time usage runs around .5 kWh.  That’s got to be phone chargers, DVR, and some other “phantom” loads from various small electronic devices that are plugged in.  The increase in usage just before sunrise is my irrigation system coming on.

The percentage of total electricity used from my solar panels was 108.  Yesterday and the day before the totals generated for both days were exactly 24.7 kWH. That’s why I think this is a good measure of the maximum my system can generate under ideal conditions in mid-March.  Because of differences in my usage, there is a slight difference in the percentage generated for yesterday and the day before.




The last ten days are shown below in both graphic and tabular form. So far, we have had three 100 percent plus days and one 90 percent plus day.

Worst Case

Yesterday, March 3, 2107, was overcast and gray all day long.  We even had some light showers.  It was probably a worst case day for solar energy generation.  Even so, we generated 28 percent of our energy from the sun.  This ends. a series of very good days up in the 80 percent range.  Our best days are ahead in the months of April and May.  My energy efficient window replacement project should be done by then so I am optimistic about how well the system will perform then.  The time-lapse for the day reveals some opportunities for generation were available in the morning.

Worst Case Scenario

January 29, 2017, was cold, cloudy, and rainy, a worse case scenario for our photovoltaic system.  I stood the chill as long as I could, but finally gave in and turned on my electric heat.  Because of the clouds, our solar panels only generated 1.9 KWH of energy while the heat used over 30 KWH.  The percentage from solar shown in the chart is the result. The chart below shows a very atypical day where all of our energy came from the grid and none from our solar panels.

The chart below shows the last ten days of percentage from solar. We were doing quite well actually until the cold front came down and stalled over us.

A Productive Winter Day

Almost a perfect day for solar yesterday. A/C was off most of the day. Ran it briefly during the night to take the humidity down a notch for sleeping. These are still the shortest days of the year.  Firstly, you see my daily percentage meter for yesterday, followed by my hourly consumption chart.   At the bottom of this post,  is the time-lapse video for the daylight hours yesterday.  You can see that the day was not unusually clear.  The temperatures were mild so the A/C was off for most of the day.  I turned it on briefly in the evening to drop the humidity, you can see that in the hourly chart by the noticeable increase in grid consumption around 11 pm.   My irrigation system also ran in the early hours of the morning.  Notice in the time-lapse,, that the sun is still very low on the horizon and is hardly visible in the video.

2016 Year End Analysis

Here’s the histogram for last year’s daily percentage electricity from our solar panels. It gives a good overall picture of the characteristics of our system.  The year started with unusually high consumption for a variety of reasons.  Nevertheless, you can see that we had more days above 50 percent than below.  With more increases in efficiency, I should be able to shift that peak some more to the right. You can mouse over the bars to display individual day values.

Rainy Season

We are well into the rainy season now so the clouds have impacted our electrical generation from our solar panels. Back in the spring with cooler temperatures and clear skies we were generating one hundred percent of our energy and more. Now we are consistently down in the forty to fifty percent range. That’s running the air conditioning pretty much around the clock.