First solar-panels

Originally installed power (mid 2004): 440 Wp:
These panels are mounted on a tiled roof with azimuth 164° and are marked with a 'B' in the picture below (under "Extension #1"). The tilt of the roof is 60°. 

In the spring of 2005 I was looking for an extension and since I have still enough roof available (although with another azimuth and tilt), I looked for the best Euro/Wp ratio. I found a good deal at www.solaraccess.nl for a Sharp/Gridfit system. Since I did not want to come into problems with extensions afterwards, I needed 6 panels at once. That was above budget at the time. I still had space next to the original installed system for two or three panels, but then it had to be the same Isofoton panels (I think that a system has to look nice besides performing well...).

While thinking about what to do, Solaraccess informed me that Isofoton would stop producing the I-110 panels mid 2005! So, I decided to get another two extra Isofoton panels with another Gridfit-250 inverter, although the Euro/WP ratio was slightly higher.... So:

Extension #1
Installed power: 220 Wp:
These panels are mounted on a tiled roof with azimuth 164°, seamless attached to the originally mounted panels and are marked with a "1" in the picture below. The tilt of the roof is 60°.
Base system and extension #1

In the spring of 2006 I was again looking for an extension. This time I wanted a system mounted on a flat part of the roof. I asked several suppliers to give me a good offer. I got an offer from Solaraccess, Dbcom and Solarnrg. No word from the other companies. Dbcom had the best offer to my opinion. A long time later I got called by Esdec. They seemed to have send me an offer, but I guess it got lost in cyberspace due to my spamfilter (sorry for that!).

Dbcom offered 500 Wp (4 x Kyocera 125Wp) with 2 Gridfit-250 inverters. Dbcom offered a smart solution with one part of the panels placed of the flat part of the roof, and the other part mounted to the tiled part of the roof. On 10 March 2006 I installed the panels. So:

Extension #2:

Installed power: 500 Wp:
These panels are mounted on a tiled roof with azimuth 254°. The tilt of the panels is 25°. On the picture below you can see them, together with the solarcollector for the heating of water.
Extension #2


In the spring of 2007 I was looking for an extension for the third time. This time I had again a limited budget. After extension #2 there still was some room left next to the four panels.  I asked Dbcom an offer for a fifth 125Wp Kyocera and a Soladin 600 inverter.

In June 2007 I installed the 5th Kyocera, which is actually a 130Wp version. I connected the five panels as 1 string and also installed the Soladin inverter. So:

Extension #3

Installed power: 125 Wp:
This additional panel is mounted on a tiled roof with azimuth 254°, next to the existing 4 panels. The tilt of the panels is 25°. On the picture below you can see them, together with the solarcollector for the heating of water.
extension #3


In the winter of 2008 I was looking for an extension for the fourth time. This time I wanted a system mounted above extension #2 and #3. I figured out that The Kyocera 85Wp modules should just fit. I ordered 4 Kyocera 85Wp at Dbcom. I actually received 87Wp panels. I could reuse the 2 gridfits 250 I still had when I replaced them for a Soladin 600 for extension 3. Installation was done in August 2009 (due to lack of time). So:

Extension #4

Installed power: 348 Wp:
A picture of this installation will follow

Measurements

The inverters are divided into three groups, which I call systems:
Each system is connected to a single phase ac watt-hour meter. This meter is equipped with a so called S0 impulse output. This output will give one impuls every 0.5 Wh. The impules of these watt-hour meters are fed into a microcontroller circuit. This circuit stores the impulses. Periodically, the pulse count is send wireless to my Linux-server (over a Zigbee network).

Based on these impulses software on the server calculates the produced power in one-minute intervals. This results in a minimum measurement resolution of 30 Watts (0.5 Wh/minute * 60 minutes = 30 W). Since this resolution will give quite rough (stepped) results, the software also calculates the five-minute sliding average. This will give a minumum resolution of 6 Watts (0.5 Wh/5 minutes *12 = 6 W). Finally, these values are logged on disk every minute.

Other scripts on the server will calculate some stats and graphs. Every minute these graphs are updated. A client-side script will reload these graphs every minute.