Eli Hunter avatar image
Eli Hunter asked

Scheduled charging without ESS

Hi, I just switched on my installation of 2 Multiplus 3000s and a Venus GX and am now looking at scheduling power draw from the grid. I'm in the US and have a grid tied SMA inverter in parallel with the Multiplus. Since I can't set a grid code here I can't use ESS.

I'm able to handle turning on and off AC input with modbus but couldn't find a way to disable charging without using one of the relays which I'd prefer to avoid just to keep wiring nicer. It looks like there's no way to disable charging or set the DVCC limit to 0 over modbus without ESS, is that correct? Any workarounds?

ESSModbus TCPmodifications
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Eli Hunter avatar image
Eli Hunter answered ·

I was able to get this working using com.victronenergy.settings slave 100, register 2705. Since the Modbus Excel doc mentioned ESS mode 2 I didn't think it would work but tried it and I can set the DVCC current with this without ESS assistants loaded.

In case it's useful for anybody I'm using this in Home Assistant, you can use the below code.
I used 1 amp for command_off so it should provide enough power for the Venus GX and BMS. Changing that to -1 should disable the charger completely.

Add in configuration.yaml

modbus: !include modbus.yaml
  - platform: modbus
    - name: Grid Enable
      hub: victron
      slave: 242
      register: 33
      command_on: 3
      command_off: 2
    - name: Charge Enable
      hub: victron
      slave: 100
      register: 2705
      command_on: 40
      command_off: 1

And modbus.yaml

name: victron
type: tcp
host: 192.168.x.x (your Venus GX/CCGX IP)
port: 502

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources

Modbus TCP Basics

Experiments, Modifications and Adaptions. Mods (Modifications) can be made to Victron Software by the Community. Please use the modifications space for enthusiasts who want to push what is possible, without official Victron Support.

What is ESS training video

ESS Quick Installation Guide

ESS design and installation manual