Utility company meter recording battery consumption as grid consumption

[Riverman]

I wonder if the members of this forum can help me solve the following, frustrating puzzle?

In June this year, following a roof renovation, I had a PV panels and a SolarEdge battery (10kWh capacity) installed at my home in Belgium. My utility company meter is a twin rate meter, recording off-peak and peak consumption separately. At the end of October, the grid operator (Sibelga) replaced my old meter with a new, smart meter which also records off-peak and peak consumption separately (though of course now also keeps separate indexes on the electricity which I inject into the grid during the peak and off-peak hours). Off peak hours include 2200h to 0700h on weekdays, and all weekend.

The problem which I am experiencing is that the utility company meter seems to record all consumption as grid consumption. In other words, when the SolarEdge monitoring data show that my import of electricity from the grid is very low, or even zero (e.g. when I am consuming stored electricity from my battery) the Sibelga smart meter nevertheless continues to advance. It is almost as if the Sibelga meter cannot distinguish between my consumption from the grid and my consumption from my battery.

The following data illustrate the problem:

Sibelga off-peak meter index at 0836h on Friday 3 November 2023 = 21.307 kWh (at the time of this reading, in the morning of Friday, the off-peak tariff was no longer in effect so the off-peak meter was static)

Sibelga off-peak meter index at 1333h on Saturday 4 November 2023 = 25.116 kWh

Therefore, according to the Sibelga meter, total electricity consumption from the grid between 2200h on 3 November (when the off-peak hours started again) and 1333h on 4 November is 3.809 kWh.

By contrast, the SolarEdge charts from Saturday 4 November (see chart below) shows consumption from the grid between 0000h and approximately 1330h on 4 november as only 0.81 kwh. (Of the total 3.49 kWh consumption recorded in the SolarEdge data, 2.51 kWh is recorded as battery consumption). The detailed Solar Edge data (i.e. the downloadable CSV files) confirm that the battery is being discharged during this time and very little electricity is being imported from the grid (certainly nowhere near 3.8 kWh)!

Please do any forum members have any clues or suggestions as to what could be going on here? It's very frustrating because I appear not to be deriving any economic benefit at all from this very expensive battery in my system.

 

[Solar Guppy]

What the graph is not showing is your home energy loads during the the time period of grid consumption in red. The battery has limited output in kW ( not capacity ) to provide and if the home load plus solar is more than battery max output and pv, it will have to import from the grid. ( looks like ~9am to 11 am )

Also the energy your talking about is less than a single kwh and the battery is providing 2.68 kw, so there is benefit, not just 100%

Here is the manual for Storedge

 

[Riverman]

Thank you for your reply. Well noted about the limited output of the battery.

The SolarEdge chart makes perfect sense (and as you note, I was clearly relying on the grid to a large extent during the morning) but I still don't understand why my utility company meter has recorded 3.8 kWh of consumption during a period of time when the SolarEdge data suggest that only 0.81 kWh has been taken from the grid (with the rest coming from the battery)?

 

[400bird]

To best answer that, you'll need to show how everything is wired up. It sounds like the battery output is wired through the utility meter.

 

[Steve_S]

To best answer that, you'll need to show how everything is wired up. It sounds like the battery output is wired through the utility meter.

This is also my first reaction because it has happened and been written about many times... In some cases it was out of stupidity by installers and a few cases where it was just intentional to shaft customers by hostile power co's. Feeding back to grid can be frought with problems and complications if things are not "just right".

 

[Riverman]

Thanks so much for the helpful replies. The installer is going to visit on Wednesday to check things. In the meantime I enclose a picture of the wiring plan. Presumably this shows what things should look like. Remains to be seen whether the physical wiring is done correctly. It does sound like an installation problem. The fact that the wiring plan below has the serial numbers (partially obscured) for the inverter and the green meter mixed up makes me think that the installer may have been tired towards the end of the job when he was working on the wiring between the battery and the electrical box. To be fair to the guy, on the day in question it was extremely hot and he'd been on the roof for hours.

I think that the 'green meter' (compteur vert) which is installed in the electrical box may somehow be linked to my problem. During the installation the installer told me that it's used to measure the total production from my panels. It certainly does that, and its present reading accords with the Solar Edge total production data. However, it is a bidirectional green meter and according to the local regulator (Brugel) here in Brussels, it should also be configured to separately give me a kWh consumption (i.e. grid consumption) value. Brugel stipulate that in systems where there is a battery, the 'green meter' in the box should record both values. However, cycling through the various values on the touch screen display, I cannot see any value for consumption on the 'green meter' (which makes me wonder where the SolarEdge monitoring tool is getting its grid consumption data from).