Multiplus II external control signals

DIY
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1

Hi,

I’m looking for some advice before purchasing a 48/5000 multiplus II for a home battery system. Basically I’ll be storing energy when electricity rates are cheap, then running the house, maybe exporting when rates are high.

I have my own microcontroller platform that will be controlling the new multiplus II depending on the half hourly electricity price. I’d like the multiplus II to operate in one of the following modes as my microcontroller dictates:

  1. Charge batteries.
  2. Discharge for self-consumption, so run the house, but not export power.
  3. Discharge to export, so ignore the reading from grid CT clamp.
  4. Idle, no charging or discharging.

From research I initially thought I’d need a cerbo GX to achieve this, but surely this is possible just using the two auxiliary, plus temperature, remote on/off, inputs on the multiplus II directly?

I’ve downloaded the VE Configure software and had a look at the ‘assistants’ but cannot find anything that will allow the required external control of the multiplus.

Can anyone please help with exactly how I could set this up on the victron? Or am I completely wrong here.

Thanks!

2

The normal Victron way to achieve this is with a Cerbo GX acting as a central controller, providing ModbusTCP and MQQT services. From there you can control the Multiplus. I would think that the ESS Assistant would provide a number of the features you need.

I don’t know a way to do this directly without the Cerbo GX.
You can also run Venus OS on a raspberry pi instead, but you still need a VE.Bus interface to control the Multiplus.

3

Thank you. I’ll investigate the Venus OS, hadn’t come across that one.
I also see a ‘Multiplus II GX’ unit available, is this incorporating a Cerbo GX functionality? I could interface using ModbusTCP from my microcontroller, I see the protocol is published by Victron.

4

Integrated GX controllers work the same way as a Cerbo.

https://www.victronenergy.com/live/ccgx:modbustcp_faq

https://www.victronenergy.com/upload/documents/CCGX-Modbus-TCP-register-list-3.50.xlsx

5

Dan, are you in the UK?

6

Yes, UK.

7

Are you with Octopus? If so Victron Dynamic ESS supports Agile.