Domoticz

Hello
I would like to use the overproduction from photovoltaics that goes into the power grid, and in Poland it is not very profitable to send energy from photovoltaic panels to the power grid.

I installed 3x PZEM 004T from Tasmota on the main wires supplying the house, so I can see the energy that devices in the house are drawing.

I installed 3x PZEM 004T from Tasmota on the main wires from the inverter / converter, thanks to which I have readings and the W gives the inverter / Inverter.

I installed a heater in the tank, which is switched on by the EARU 63A module - currently switched on using blockly if the value on the PZEM 004T mounted on the inverter exceeds 2000.

It is known that on the circuits in the house there are different energy consumptions, sometimes higher, sometimes lower, charging from the sun, I would also like some script that would see the difference between the readings and in the case of free W turn on the heater.
Unfortunately, I have no indication from the inverter of the energy that is fed into the power grid.

@psubiaco please watch it in your free time.

Why not using professional meters like DTS238-4 ZN/S connected to the grid? It's bidirectional so you can read
1000 => you're importing 1kW
-1000 => you're exporting 2kW
Then, to make a good automation, you should consider
* current state (on/off) of the heater
* exported power
* boiler tank temperature
* hour of the day
to decide if turning on the heater or not, based on water temperature, current time (and your needs), produced power.
Forget blocky and write a script in dzVents (I don't use it, because do not understand its syntax) or Lua (very simple for a programmer beginner).

I suggested to check the script_time_heatpump_emmeti.lua in https://github.com/CreasolTech/domoticz_lua_scripts , but that script is written to control a heat pump so it can vary the power consumption to consume most energy from the photovoltaic. In you case you have a heater with on/off control.

There is nothing to stop you from buying the right meter, I saw that for Eastron SDM630 there is a typical plugin for its operation.

Together with the SOFAR HYD15KTL-3PH Inverter I have the DTSU666 meter, but Sofar also has communication. In the instructions I read that the Inverter can be connected to the computer via RS485 additionally via RS485, but from other pins of the inverter the meter that was included with the inverter is connected.

Maybe the first thing you need to do is to create communication Domoticz <-> Sofar HYD15KTL-3PH
For you, such a plugin or building communication is probably a piece of cake, but many people lack it.

So I guess the heater consumes 2000 W as soon as it is switched on and therefore you only want to switch it on if you have a surplus of 2000 W, i.e. 2000W unused solar energy?

You don't want to switch it on if the surplus is 1000W because then you would still draw the other 1000 from the grid?

In that case, indeed you are missing one factor in the equasion. So you need either the bidirectional meter like psubiaco suggested or you need another way to read the feed into the grid. You have no possiblity to read out the electricity meter (like the smart meters with a P1 port) ?

If you want to switch on the heater even if the surplus is lower than 2000 then you could just monitor the supply from the grid and if it turns zero switch on the heater, but I guess that is not what you want.

I myself use a solution that supplies energy back to an electric boiler by means of PWM, for which I use the following solution.

https://flows.nodered.org/flow/f5fa8e9e ... 2389276f3d