Graph comparisons CC vs GPM vs ASC

Tuesday, May 17th, 2011 Monitoring No Comments

The following images are screen shots of the graphs from Current Cost, Google Powermeter & AS Control.

They are all for the 17th May 2011. I took the screen shots at around 10pm, so the totals for the Current Cost and Google Powermeter graphs aren’t finalised due to the “always” on current due to the Inverter’s EMC filter that I mentioned in this post >> Monitoring via Current Cost and Google Powermeter.

The graphs are similar in shape but at 10pm the totals are different. AC Control shows 2.44kWh for the daily total. This would be the accurate figure from the inverter. The Current Cost Dashboard shows 2.85kWh @ 10pm. The Google Powermeter shows 2.8kWh. At the very end of the day the 3 totals were ASC = 2.44kWh, CC = 2.94kWh & GPM = 2.9kWh.

For the full 24 hours of the 14th May ASC reported 4.11kWh, CC reported 4.56kWh and GPM reported 4.4kWh. I have seen bigger differences than this. The gaps should close up later in the year when the solar system is generating a fair bit more power and the incorrect “always on” load won’t have as much of an effect on the daily total.

The AS Control program updates every 60 seconds (but I think the inverter internally updates a bit more often that that), the Current Cost Dashboard updates every 5 minutes and the Google Powermeter updates every 10 minutes. This sample rate difference probably contributes toward the error.

All of the images are “click for a bigger one”

AS Control 17th May 2011 a lousey 2.44kWh