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jeromed avatar image
jeromed asked

Node red : Multiplus II primary relay

Dear all,

My installation consists of solar panels, Pylontech batteries, a Multiplus II, and a Solar Charger MPPT 450/100. This set is controlled by a CERBO GX. I have installed Venus Large and Node-RED.

I already control a hot water tank from a CERBO GX relay programmed with Node-RED.

I would also like to program the primary relay of the Multiplus II via Node-RED. I can do this with the Relay Assistant but cannot find it with Node-RED. Do you have an idea?

Jérôme

Multiplus-IIRelayNode-RED
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2 Answers
liam-hogan avatar image
liam-hogan answered ·

Hi @JeromeD

Controlling the relays in the Multiplus (including AC relays and AUX relay) are currently not possible through Node-RED unfortunately.

It is my understanding that this is due to a firmware limitation in the Multiplus units themselves, so adding the feature would mean updating the firmware on every Multiplus which is not something the team is planning on doing right now.

This has been mentioned a few times on the forum and also on the Victron Node-RED github like here: https://github.com/victronenergy/node-red-contrib-victron/issues/99

You could use the second relay in the Cerbo if you need to switch something else.

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jeromed avatar image
jeromed answered ·

Hi @Liam Hogan ,

Thank you very much for this clear and detailed answer. :) It will save me time searching for the relay in the Node-RED interface.

Nevertheless what a pity to be limited to the 2 relays of the CERBO GX.

Node-RED interest, is precisely to be able to control loads in a smart way (hot water tank, EV charging, pump, standby...). 2 relays only, it's not that much :o(.

I hope that updates will allow to remedy it soon.

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liam-hogan avatar image liam-hogan commented ·
This sort of thing is indeed one of the reasons for implementing the Node-RED system on Venus. But it just so happens in this case that it's a limitation built into the physical Multiplus devices and is not something that is easily fixed or made available in software.


If you require more relays to control than the two in the Cerbo, there are other ways to do this (albeit requiring a bit of technical know-how) like using a USB relay board or one that is controllable over the network using MODBUS, MQTT, websockets etc. You could then integrate control for those into Node-RED.

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