question

Matthew Spiller avatar image
Matthew Spiller asked

VRM Total Solar does not match Solaredge inverters Total Yield

Hi,

I've got 1 x Multiplus II 5000 inverter, Cerbo GX, 2 x Pylontech US5000 Batteries and Two Solaredge Grid Tied Inverters. One is a SE4000H and the other SE6000H. The 4k is on the AC1-OUT side and the 6K on the AC-IN side of the Multiplus. I'm using the solaredge meter A-V-400Y-3MTR-S with clamps for the solaredge monitoring and the ET112 for the multiplus.

I'm confident both meters are reading correctly as both read the grid power flow exactly the same and the totals match my electricity bills over the last year. The VRM is also showing correct wattages from both inverters and the grid.

The issue is on the VRM the total solar yield is never correct and always lower. I know that it shows the total over 24hrs so if the previous days production is visible on the widget it includes that in the total. But with just a single days production showing of the graph widget the total is never correct.

img-0060.pngimg-0061.png

Solar wattage reporting on both monitoring platforms closely match each other:


screenshot-2024-04-07-132450.png

screenshot-2024-04-07-132338.png

If you look at the monitoring for last month it's clearer and very consistently lower on VRM by 10ish KWh per day:

screenshot-2024-04-07-122640.png

They're not exactly perfectly consistent, if you look at the 27th, VRM reports that was a good solar day but solaredge says the 22nd was.

screenshot-2024-04-07-122606.png


I thought maybe it was only reading the totals from one inverter but this doesn't match either:

screenshot-2024-04-07-130152.png

Any ideas what's going on here?

Thanks

VRMEnergy Metersolarsolaredge
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1 Answer
Alexandra avatar image
Alexandra answered ·

@Matthew Spiller

Solar edge use CTs and the Eat is a shunt system. So would already be slightly different in measurements.

Then it is possible that the accuracy (decimal places used) is different and there is a cumulative different in the maths. And data sampling would change totals as well.

Third contributor is conversion losses. And the system (solar edge) own self consumption. Not as cut and dried as this but if it is at 96% efficiency then that already a 4% difference between the two systems.

Not sure how they differentiate in power factor if that is taken into account either.

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