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paulcooper avatar image
paulcooper asked

Controlling an openEVSE electric vehicle charger using Node-Red and MQTT

This is not so much a question but more of offering what I have created to others in the community. I have been using the Node-Red add-on in Venus OS v2.70~5-large-18 to control my openEVSE car charger via MQTT. It maximises the available power from the PV array to charge the car. When there isn't enough power it will use what is stored in my BYD batteries and when they're depleted it uses the mains. It is now stable enough that I have placed the json file and a brief explanation on GitHub (https://github.com/thepaulcooper/victron-openEVSE).

Disclaimer: I am not an expert in JavaScript or Node-Red so I am sure there are more effective ways of coding what I have created. But it works and I am now charging my car from the sun.

Venus OSBYDNode-REDMQTT
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3 Answers
babvictron avatar image
babvictron answered ·

I hope you see this even though you posted like a year ago. Would a similar mqtt/node red setup work for doing load sharing where say you have 20 chargers you have to share 100Amps between? If only two cars are plugged in they get full charge, but 10 cars get 10amps each until they reach their charge limit? The more cars that reach their charge limit allows other cars to charge faster.

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paulcooper avatar image paulcooper commented ·

In theory, yes. The charging devices would need to be controllable via MQTT messaging (or similar). The openEVSE charger is one such device. You would need to set the maximum charging current on each charger to 6A (the minimum permitted on the openEVSE) and then step-up the current on all connected devices until the total is up to 100A. You would then poll all in-use chargers for their actual current and adjust the current on the others to bring the total up to 100A. You would also need to poll for new vehicles and recalculate the charging currents accordingly. It would clearly need some fail-safe measures and some significant hardware safety devices but an interesting project nonetheless.

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paulcooper answered ·

This project has been enhanced significantly. It now has 12kWh of battery and also provides power to a water heater and a space heater. The priority order is EV, water and then the space heater. All controlled by MQTT/Node-Red and some Shelly relays. I will upload the new control flows to GitHub soon.

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xavier-65 avatar image
xavier-65 answered ·

Hello Paul,


I am new to this community and also new to victron world (still waiting to receive my full set up to install i!t). I am very interrested in what you have done with open evse & victron using mqtt. I was not able to find the 12kWh script on Git. Could you pease share your work?


Thanks!

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