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Meter2Power
Posted: Sat Apr 08, 2023 8:40 am
by graham
Does anybody know what the measured parameter Meter2Power is meant to be?
On my system, for the Inverter Model : AC1-5.0-E, it looks like it's the negative of power combined from both sets of panels. But the name and sign are confusing me. But it's the only measured parameter I can find that gives that total solar power that I want to meter.
Sorry if I'm not using the right nomenclature. At least I'm not using many TLAs and ETLAs.
Graham
Re: Meter2Power
Posted: Sun Apr 09, 2023 8:55 am
by Dave Foster
Meter2Power is the second input on the inverter (CT2/Meter2), it is used to read any external generation.
In this case I would assume it will be on the output of your other solar inverter - and it would show the combined output of that inverter as a negative value which it deducts from the first meter/CT to work out how much solar generation is left for it to charge it's batteries.
It also handily will record the absolute generation of your other solar inverter.
Re: Meter2Power
Posted: Sun Apr 09, 2023 10:19 am
by graham
Unfortunately, I'm not sure I'm very much wiser.
MeterPower is exactly the same as GridConsumptionPower. So I suppose the difference (Meter2Power being negative) is the power going into the inverter-charger from the two sources, grid and solar. So, after allowing for the losses, that gives ChargePower going to the battery.
But why is Meter2Power negative?
Is there a primer on what these parameters are, i.e. one that actually explains them, even if in technical details.
Re: Meter2Power
Posted: Mon Apr 10, 2023 10:36 am
by Dave Foster
Unfortunately no primers, sadly the weakest side of FoxESS is user documentation, I think that's one of the main reasons William created these forums to provide advice.
On the MeterPower, that is your main meter/CT reading, it should be fitted on the live tail of your utility meter. It provides information to the inverter which allows it to create additional sensors. When the value is positive it is reading Grid Consumption but it also goes negative when it sees export to the grid and this is shown in the feedin sensor.
Following on from that logic anything negative is an export which is why your Meter2Power (second CT) reads negative - your AC inverter doesn't know what kind of generation it is (solar, wind, water etc..) just that something is exporting power which is a negative value.
These are then used internally to the inverter to be able to calculate how much generation there is, how much grid consumption, feed in and house load.
Re: Meter2Power
Posted: Mon Apr 10, 2023 3:37 pm
by graham
Dave Foster wrote: ↑Mon Apr 10, 2023 10:36 am
Unfortunately no primers, sadly the weakest side of FoxESS is user documentation, I think that's one of the main reasons William created these forums to provide advice.
On the MeterPower, that is your main meter/CT reading, it should be fitted on the live tail of your utility meter. It provides information to the inverter which allows it to create additional sensors. When the value is positive it is reading Grid Consumption but it also goes negative when it sees export to the grid and this is shown in the feedin sensor.
Following on from that logic anything negative is an export which is why your Meter2Power (second CT) reads negative - your AC inverter doesn't know what kind of generation it is (solar, wind, water etc..) just that something is exporting power which is a negative value.
These are then used internally to the inverter to be able to calculate how much generation there is, how much grid consumption, feed in and house load.
So which does what to whom for how much is all heuristics then?
Iv'e been trying v. hard not to export, so I didn't see that MeterPower is GridConsumption Power minus Feed-In Power, but I looked back a bit to when I failed and see it is. So thanks for the correction.
I can see the logic in that MeterPower being GridConsumption Power minus Feed-In Power - they have opposite signs from the perspective of the meter. But I'm not sure that I quite see the logic in solar power coming from the two panel inverters into the battery's AC charger is negative, where power coming from the grid to the AC charger is positive - they have the same sign to the battery. And I may be applying the flow diagram of the app a bit literally there - though the logic in MeterPower does match those flows. But I realize when I've just got to accept things that are what they are.
Graham