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tuxedo0801 asked

Why does VRM monthly grid consumption not match EM24 meter reading?

Hi guys,

I have a 3-phase ESS setup with EM24 as a grid meter, connected via RS485 USB to CerboGX. Live values etc. shown in VRM look correct. But for example my monthly grid consumption for april is, according to VRM 75kWh..., But I noted the EM24 meter reading start and end of april and the diff is only 57kWh. Why does VRM show me 75kWh if it's only 57kWh? It's about 24% off...

The official grid meter from my energy supplier tells me also 57kWh if I do the meter reading diff between 1st of april and 31st of april.


So, EM24 and official meter tell me both the same: 57kWh.
But VRM, which get's its value from EM24 via CerboGX tells me 75kWh.

My guess is: Internally VRM get's also a kWh meter reading and regulary calcs the delta.. And here it some rounding error accumulates ...

Isn't there a way to get reliable historical values from VMR? I mean... the live data looks okay, values seem to be realistic.

br,
Alex



[update]

The grid feed-in (>750kWh in april) is just about 3% off... So I guess it must have to do with the amount/values the VRM gets from the EM24... consumption is very low, and feed-in is much higher.
Most of the time, my system is running from battery and the grid consumption is just 0,1kWh per day or so.
My current guess is: My grid consumption is not exactly 0,1kWh, but f.i. between 0,05kWh and 0,1kWh ... So the values get rounded up to 0,1kWh. And this causes the final value in VRM beeing 24% off the real value when looking at a whole month.
Does anyone know how precise VRM is storing the values?

VRMem24
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1 Answer
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tuxedo0801 answered ·

Not anyone... really?

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