Steve's Blog

Monitoring via Current Cost and Google Powermeter

In addition to using the EverSolar PMU to monitor my solar generation, I also have a Current Cost EnviR and Bridge installed. It uploads it data to the Current Cost Dashboard and that uploads the data to the Google Power meter.

Current Cost Dashboard Screen Shot

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Google Powermeter Screen Shot

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Rehashing a lot of what I mentioned in this post My solar monitoring in the 1st week (or so) there are some disadvantages to using the Current Cost EnviR.

The BIG drawback using the EnviR. The final EMC filter in the inverter is after the AC anti islanding disconnect contactor. I’m not sure what it consists of, probably an inductor and a capacitor network and it draws current while the Utility AC is on. I’ve not put my actual watt meter on it, but I imagine the wattages is very, very low. It’s just the “apparent” power (VA) registers 35W 24/7. The “Real” power (W) would be negligible.

Seeing as the Current Cost device is really just an ammeter calibrated to display W and calculate kWh it registers apparent power. It can’t detect current flow direction either so can’t differentiate between Feed In and Feed Out. So when the unit is sleeping, the Current Cost Dashboard and the Google Powermeter are both showing an always on load of 35W which is inaccurate. 35W over a 24 hour period = 0.84kWh per day that I didn’t generate (or consume).

The actual figure is less than 0.84kWh because when the inverter is awake and generating power, the 35W is no longer counted. So at the moment (May) if the inverter is generating something between 8:00am to 5:00pm for 9 hours, the difference is (24 hours X 35W) – (13 hours X 35W) = 0.525kW/h per day (840Wh – 315Wh = 525Wh = 0.525kWh). 0.525kWh X 365 days is a little over 191kWh per year. On a system that might generate 2200~2300kWh per year, it is an 8.7~8.3% difference; too much for me.

The other thing about the current Cost dashboard is that it updates every 5 minutes and the Google Powermeter updates every 10 minutes, I wanted better resolution than that. (You don’t need a bridge and can run the Current Cost software on your PC, but you need the PC on while the Solar System is generating. I want to export as much as I can and use the minimum amount of power as possible while the Solar is working, so running a computer the whole time defeats the purpose.)

To keep a better eye on my Solar System, I purchased an EverSolar PMU (Power Management Unit). I’ll add a link here when I’ve created a page for it. Here is the link >> Accessing the Eversolar PMU remotely

Tags: CC, GPM, Powermeter

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