Solar power is collected by 32 CEEG SST190-72M-Black solar panels, each measuring 1.25 m2 and capable of delivering 190 Wp, for a total of 40 m2 and 6080 Wp.
The panels are arranged in 4 "strings" of each 8 series-connected panels. Two groups of each 2 parallel-connected strings each feed a Chint CPS SC2.8KTL power inverter, each connected to a different phase of the grid.
NOTE: One of the inverters failed after 7 years of service (out of warranty) and was replaced by a Solis-1P3K-4G
The Chint inverter provides a somewhat primitive monitoring facility, requiring a wired RS-232 connection to a computer in order to extract the operating parameters and power data. Its electronics are fed from the solar panels (not from the grid), so it shuts down completely at night, and thus -lacking internet connectivity or a real-time clock- is unaware of time and date.
Therefore, a monitoring system has been programmed in the Python language. I used -and slightly modified- a freeware driver module "pv" 0.2, written by Edmund Tse (http://pv.codeplex.com/) for different but compatible inverters. Data are taken at 1-minute intervals and recorded in an sqlite database.
The Solis inverter is provided with a WiFi datalogging "stick", which by default transmits its data to a Chinese website. In order to avoid dependency on this foreign monitoring website, a local monitoring system was built along the lines demonstrated by XtheOne, Wouterr and others.
The main web page requests data -using an Ajax technique- by calling a server-side python script that extracts the data from the database.
This web page itself is mainly written in JavaScript. The graphical representation is performed by a free plotting library Envision, provided by Carl Sutherland of Humble Software.
After the Chint breakdown, an effort was made to provide a graphical monitoring web page that is automatically updated by server push, using websockets and that could be completely written and maintained in Python. For that, data visualization library Bokeh was used, that runs on a specific (included) webserver Tornado. The Tornado-based Bokeh web page is served as a reverse proxy by a virtual host on the main Apache server.
It turned out that the client-side Bokeh-generated javascript was rather heavy on older laptops and mobile devices. Therefore, main page keeps using the Envision library, while the new Bokeh-based page is accessible through the Alternative link.
The server software runs on a cheap low-power HP server Proliant MicroServer Gen8 netbook under the Lubuntu 18.04 operating system.
The solar panels and the inverters have been acquired through the Wij Willen Zon project initiated by Urgenda. The panels have been installed on a south-oriented 45-degree roof by AgroNRG in June 2011.
You can get more details by mailing me at [nam]@[dom], where [nam] is info and [dom] is weerridder.nl.