Best registers to Enable/Disable multiplus via Modbus?

Hello everyone, I would need your recommandations on a specific subject, I hope you will be able to help me! :slight_smile:

I’ve recently installed in my house a Multiplus 2 combined with existing solar panels (Solaredge inverter) and 4 Pylontech batteries for ESS purpose, everything seems to be working well!

My wife has an electric car and she’s using a Wallbox charger with current sensor which is able to use only the production from the solar panel and as you can imagine when the multiplus and the EV charger are both connected/working, they create some concurrency issues because both try to use the electricity generated by the solar panels.

To solve this, I managed to create an integration with Home assistant, so when EV charger is plugged in the car, I changed ESS settings through modbus, registers 2704 & 2705 to limit multiplus charger and inverter power to 50w.
It works but it’s not perfect, it seems the regulation takes some time to reach the new limits, I also tried to set 0 watt on both parameters but the multiplus is doing a weird noise, I guess it’s not a good option.

Reading at the Excel file with all registers available, I see there is multiple registers named /Mode where it seems I can turn off by software the system but I don’t feel confident to “play” with them. :smiley: :smiley:

What I think could be interesting for me to disable/enable the multiplus in a soft manner when our car is charging:

  • Inverter on/off/eco (register 3126): on/off/eco
  • Switch position - Multi (register 4531) : on/off
  • Switch position - VEBus (register 33) : on/off
  • Charger on/off (register 2317) : on/off
  • Inverter on/off/eco (register 3126): on/off/eco

Do you know which one would be the most appropriate to enable/disable the multiplus operations and if it would be safe to use them? (I don’t want to have inconsistent state or reset everything now)

Many thanks for your help,

Benoit

MP2 is a VEBus device. Try 33.
But all that it’s powered by MP2 will turn off this way… Is this OK?

Thanks Alex!

I think I need a solution where multiplus remains powered.

I already played with the remote control physical connection available on the MP2 panel and a relay but it’s a little bit rude for the electronic of the MP2 to shutdown it this way.
The main problem of this is when the EV charge is complete, the relay is turning on the multiplus back but unfortunately ESS is not restarting. I suppose this is because the battery and cerbo GX are remaining powered all the time (even when the multiplus is off) and they enter in a kind of fault state and I need to restart them to make ESS working.

Do you think it’s safe to play with the registers I mentioned (3126 & 2317)? I can do some testing but I don’t want to do a big mistake.

Thanksss

I believe those registers refers to different devices / hardware.
3126 - com.victronenergy.inverter - VE.Direct inverters & Inverter RS
2317 - com.victronenergy.charger - AC chargers.

Also take a look here: dbus · victronenergy/venus Wiki · GitHub

To be honest, maybe a small schematic of your installation could be a good thing, in order for us to better understand what you want to accomplish…
Are you also feeding to grid?