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colj avatar image
colj asked

Cerbo GX, ESS Scheduled Charging: remote update of 'STOP on SoC'

Newbie question : About to have a Quattro, Cerbo GX and Batteries installed (already have PV). I intend to use a rpi for automation (probably with code red). I want to keep the Cerbo GX as 'pure' (= supported) as possible and use the rpi for automation/tinkering. I have read lots of documentation and cannot find a clearly documented way to remotely change the 'STOP on SoC' within Scheduled charging. Use case : I want to use a low cost overnight tariff window and automate only charging the batteries to some set point based on the PV forecast for the following day and my expected loads through the day. From the modbus-TCP xls it seems modbus is not an option? However, it looks like if VRM and 2-way communication are enabled i may be able to use MQTT? Appreciate if someone could confirm or otherwise please?

Thanks, Colin

cerbo gxESSModbus TCPMQTT
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5 Answers
djbower1 avatar image
djbower1 answered ·

This is possible with MQTT and Node-Red, but setting up and configuring all depends on your HAS, When your installer is commission the system, ask them to upgrade the Cerbo firmware to Venus OS Large v2.90. I would wait until the system is up and running before even thinking about this.


I have done something similar to what your asking but instead of using the schedule charging I use the ESS mode and charge it to Keep Charged and control this with my HAS. Changing the Schedule via MQTT is possible, but the time is formatted in seconds from midnight and I couldn't be bothered to programs my HAS to deal with that.


Once installed, have a play with Node-red and your HAS and see how you get on.

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colj avatar image colj commented ·
thank you. I haven't yet made any decision on an integrated Home Automation platform. Initially I will start by seeing if I can just use a rPi with Node Red to get the automation I need by adding MQTT nodes for the specific data I need to update.
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djbower1 avatar image djbower1 colj commented ·

If your using a Cerbo GX then just use the Venus OS Large firmware as node-red is included. The other good thing with doing it this way is it has all the nodes available to use and makes life ALOT easier. Forget the PI as it just becomes a point of failure in the system.

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de-marc avatar image
de-marc answered ·

@Djbower1, how would you format the mqtt message?

I can query the SoC successfully by using this topic: venus-home/N/xxx/settings/0/Settings/CGwacs/BatteryLife/Schedule/Charge/0/Soc

and I can also inject a message, but nothing seems to change in the cerbo...

I have the message topic the same as above

and the payload as {"value": 30}

I've also tried just to send a 30 as string or number - no avail. The cerbo itself still shows the original value.

thanks!

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de-marc avatar image
de-marc answered ·

In the meantime I worked out to change the topic from

venus-home/N/xxx/settings/0/Settings/CGwacs/BatteryLife/Schedule/Charge/0/Soc

to

venus-home/W/xxx/settings/0/Settings/CGwacs/BatteryLife/Schedule/Charge/0/Soc

(N to W), but still no avail..

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de-marc avatar image
de-marc answered ·

found the answer - put this code in the inject node, leave the topic in the MQTT node blank and it works!

venus-home/W/xxx/settings/0/Settings/CGwacs/BatteryLife/Schedule/Charge/0/Soc

1665152375890.png

thanks!


1665152375890.png (21.9 KiB)
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jschz avatar image
jschz answered ·

Hello. I want to do something similar: I want to control a transfer energy system. I have a Cervo GX but I want to include a Raspberry PI as a supervisor of the Cervo (this is the first step, in a future I want to remove the Cervo and do everything with the Raspberry), in order to introduce automation and to introduce also a more complex logic control (maybe AI) using Python.


I would appreciate a lot if you could send me the documentation that you said you have read about this topic.

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