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Old 02-20-09, 02:25 PM   #7
groar
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Quote:
Originally Posted by groar View Post
Tomorrow evening I should plug the assembly on the production meter and measure the PV production Friday as it should be a sunny day If it works then I'll order a second assembly to have both meters recorded in real time
Today was so good that it beat the record : 7.652 kWh while my forecast for February is 5.3 kWh. As the production meter emits the same data, the assembly worked I just ordered a second one to have both production and consumption logged simultaneously.
My scripts had to be changed a little as that meter is configured to have a single rate, not too rates like the consumption meter (Peak/Off peak) so keywords are different and the rrdtool database structure.

Here are the graphs I generated :
  • The intensity :

But the data is rounded at the upper integer
  • The power :

In fact it is the "apparent power" in Volt.Ampere. When the production is null or small (<70W) then the meter sends 100VA. When the production is greater then the meter sends values between 250 and 270VA. Over 300VA the data seams correct, but the peaks shown between 11:00-13:30 and 16:15-17:30 are strange...
  • The index :

In fact the graph is the difference in 2 consecutive meter readings. This works only with low resolution graphs, this is why the curve is squared. With higher resolution we see the production as pulses because the index is an integer number of Wh.

I have to improve these graphs a little...

On all the graphs, the production curve is asymmetric. This is due to the fact my solar panels are toward West. This was accentuated this morning as it was -2°C and everything was frozen, lowering the luminosity received by the panels until the thaw.

Denis.
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