question

myozone avatar image
myozone asked

Control MultiPlus II via MQTT

Would it be possible to control a MultiPlus II via MQTT ?

What I'm thinking is to disconnect the mains in relay off between 16:00 - 19:00 this would be because on the Octopus Agile tariff here in the UK is the very expensive period. During this period my house would run from batteries via the inverter in the MultiPlus II. The control would come from Node-red.

Multiplus-IINode-REDMQTT
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6 Answers
neoneddy avatar image
neoneddy answered ·

Might be possible with a raspberry pi running Venus OS, that has the MFD option via MQTT. You might be over my head, maybe I'm just adding noise here.

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Warwick Bruce Chapman avatar image
Warwick Bruce Chapman answered ·

Dunno about MQTT but with Venus OS and dbus, you could perhaps achieve this by setting the current limit to 0A in /Ac/In/1/CurrentLimit.

See more: https://github.com/victronenergy/venus/wiki/dbus

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justme avatar image
justme answered ·

Doing this soon. Will be fitting a Color GX so have the option of using the generator start relay to control a mains contactor via the quiet times setting to inhibit start or in this case grid in.

Or I have also ordered a smart plug that can be set via ITTT to switch on / off as the price set point rises & falls. The plugs have a 16 amp capacity but again I would wire via a contactor for robustness. This would allow me to fine tune charge times to only when below x pence per unit.

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myozone avatar image myozone commented ·

It'll be interesting to see how you get on.

Are you on the Navitron forum ? I sort recognize your handle

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justme avatar image justme myozone commented ·

Yes I am with a very similar handle.

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myozone avatar image myozone justme commented ·

Thought I recognized i, I'm a regular lurker.

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Vincent Royer avatar image
Vincent Royer answered ·

this is easy via node-red:





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Warwick Bruce Chapman avatar image Warwick Bruce Chapman commented ·
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myozone avatar image myozone commented ·

Ah oh that looks easy, so you can MQTT directly into the MultiPlus II ?

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Vincent Royer avatar image Vincent Royer myozone commented ·

you definitely need a gx device...

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myozone avatar image myozone Vincent Royer commented ·

Ah ok guessed as much.

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Kirk B avatar image Kirk B commented ·

What MQTT path are you writing the System Mode too? I've tried N/myid/vebus/257/Mode but it doesn't seem to take. I can read from there without issue but writing a message to that path appears to go unheard.

Thanks

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Kirk B avatar image Kirk B Kirk B commented ·

I'll answer my own question :) The N/ in the path should have been W/ in order to send a write message to the MQTT server .... doh!!!

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homestorage-77 avatar image homestorage-77 commented ·

how do I get the Victron nodes in node-red?

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homestorage-77 avatar image homestorage-77 homestorage-77 commented ·

In answer to my question;
https://github.com/victronenergy/node-red-contrib-victron#Installation-and-Usage

  1. cd to the node-red user directory, typically ~/.node-red
  2. install node-red-contrib-victron locally, npm install @victronenergy/node-red-contrib-victron
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Noisy Boysie avatar image
Noisy Boysie answered ·

found some examples you could use

https://github.com/victronenergy/node-red-contrib-victron/wiki/Example-Flows


Combining inputs

Charge batteries only using night time rates – unless the SoC is critically low

The following flow tries to maximise the electricity cost savings by charging the batteries only during night time -- unless the battery level is critically low.

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markus-001 avatar image
markus-001 answered ·

For simplicity I would put a standard digital timer on the ACin and limit the ACin current in the Multiplus to slightly lower than the curent maximum on the timer which is usually 16amps. Use power assist to get the batteries to compensate for spike demands higher than 16amps for short periods if you are using a 5kva unit. The 3kva unit should already be protected by a 16amp MCB.

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justme avatar image justme commented ·

I would not want to run a 16 amp device at 16 amps for long periods. Also the time that the energy is cheap changes on Agile so you need a more active device to track that. On Octopus's other tariffs its fixed rate periods so that could work but you only get 4 hours cheap rate.

My two units could draw nearly 30 amps if both were set on max.


The smart plug has arrived but it seems that if you are not already on Agile you cant access the data to use IFTTT to test it out.

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