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disuye avatar image
disuye asked

Set Minimim SOC % remotely via ...?

Can someone point me towards documentation about setting the Minimum SOC % remotely via either Modbus, MQTT, RPC(?) or even local ssh / shell commands if doable.

I'll take whatever messaging flavour Victron wants!

I skim read the ESS Manual and apart from Schedule Charging (not quite what I need) I saw nothing about remotely controlling Minimum SOC%. Hopefully this is achievable as I wish to adjust SOC% based on environmental, time and demand conditions.

Many thanks, Dan

ESSSOCModbus TCPMQTT
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5 Answers
ejrossouw avatar image
ejrossouw answered ·

1682156179719.png

Do you want to do more than this? Also look at the modifications space where users may have done similar you with regards to TOU.


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disuye avatar image
disuye answered ·

Hi @ejrossouw – thanks for the reply. I take TOU to mean 'off peak, battery top up from grid?' which is not quite my situation. But I'll search the modification forum later and see what I can find.

In a nutshell, I need to maintain 40% SOC at all times in case of blackout *except* when I know sunshine is imminent and I have a increase in demand (usually pre-dawn / at dawn) which the battery could handle to avoid drawing from grid.

The increase in demand at dawn is not scheduled. So it makes no sense to schedule SOC. There is the water boiler & household waking up, which the same every morning, however the bulk of additional loads are due to other Home Assistant automations (irrigation pumps based on forecast / soil moisture, borehole based on tank levels etc. etc.).

I have a Home Assistant automation that *could* intelligently adjust SOC % based on my text above ... but I'm not sure what communication method I can use to tell the Victron equipment.

Right now the HA automation sends a notification to my mobile phone, and I log into the Remote Console / VRM and make SOC % changes manually. Which is stupid :)

Thanks again! Dan

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sesshoumaru avatar image
sesshoumaru answered ·

The Minimum SOC limit can be set using Modbus (address 2901 under settings).

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disuye avatar image disuye commented ·
Yes – you're absolutely correct – and I can create an Automation in Home Assistant that 'Call Service > Modbus: Write Register' ... thanks, I'd completely overlooked that 2901 was writeable.
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tobyfw avatar image
tobyfw answered ·

I am a Victron beginner myself, but what I did is update VenusOS to the "large" image version. You can then use the graphical Node RED environment (either directly via a web browser port on your GX, or via a button in VRM which opens a proxy to your GX) to connect to any system you like (add weather nodes, MQTT, RPC nodes etc.)
nodered.pngThere are other ways to do what you want to do, but that seems to be the "slickest"


nodered.png (67.7 KiB)
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disuye avatar image disuye commented ·
Oh wow – this is entirely new to me. I'll take a look. Thanks for posting (on a Saturday night no less lol), D
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nickv avatar image
nickv answered ·

Hi Dan

I was already using MQTT with Home assistant so I integrated my Cerbo GX using that method.

Here's a another thread on the same topic:

https://community.victronenergy.com/questions/63997/home-assitant-integration-with-victron.html

Here's a nice set of instructions to get you going:

https://community.home-assistant.io/t/victron-venus-os-with-mqtt-sensors-switches-and-numbers/527931

This may be useful to find the registers you want:

https://github.com/victronenergy/dbus_modbustcp/blob/master/CCGX-Modbus-TCP-register-list.xlsx

You can also just send an empty keep alive message to the Cerbo and it will publish out everything. You'll find that you need to publish a keep alive every minute anyway to request the data you want. This is a simple automation in HA though.

Let me know if you opt for this and get stuck.
I was intending to automate my target SOC % based on Forecast.Solar integration data but so far I've found my forecast vs. actual weather to be too unpredictable. My consumption varies a lot too so I just manually set the SOC daily (in Home Assistant).


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