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miriam-schwarz asked

How to switch Phoenix Inverter based on battery SoC% via VenusOS and VE.Direct

Hi, i have a off-grid system build from a SmartSolar 100/20, a SmartShunt, a Phoenix 24/2400 and 16x Hawker SBS40 as 8P2S.


These are connected to a VenusOS-Raspberry via Original USB adapters and everything basic works as expected.

Now i search for a way to tell the Phoenix to only switch on, if the SOC is above 50%, to keep my batteries safe.
But I cant find any Option for doing so, only for using cutoff voltage, which feels a bit stupid to use when there is a known SoC% aviable to the system.

Best regards
Miriam Schwarz

smartshuntSOCdischarge level
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What type of batteries are you using?


Voltage is a reliable way to set limits, SOC is a calculation and may be incorrect sometimes.

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I am using Hawker SBS40, these are AGM-Lead acid batteries.

I bought the(not quite cheap) smartshunt mostly for this usecase, as voltages of lead acid batteries are "all over the place" depending on the situation of charging or discharging and only reflect the SoC when truly in idle.

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Okay, you can use the Generator menu to control the Relay of GX device and use that to control the remote on/off terminal of the Phoenix.
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I have put quite a lot of time and tweaking into the configuration of my Smartshunt so that it is always as close as possible to the real state of my batteries.

I cant believe that the only use of this would be to be able to manually take a look at my display to know about my batteries.
There must be a way to use this value for switching the inverter on and of, but i cant find it.

Only way i could think of at the moment is using a relaiy to open/close the remote contact on the phoenix, but that seems so stupid, given that its already conected via VE.Direct and i can even start and stop it over the internet via VRM...


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2 Answers
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shaneyake answered ·

This is an unusual use case. Voltage is good enough to protect batteries.

You can install the large version of the GX firmware which comes with NodeRed which would allow you do a custom control setup like this.

But on the standard firmware it will need to be done via a relay.

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Thank you so much.
I am now using NodeRed, which is a really intuitive and powerful tool for me now.

Setting up a SoC% to Inverter mode switch was a matter of minutes after installing the firmware and getting used to the interface and logic of NodeRed.

https://www.victronenergy.com/live/venus-os:large
This is the documentation to install and start using this, for anyone who stumbles over this here.

Have a nice day.

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elvis avatar image
elvis answered ·

If it were me, I might create a cron job to check the SOC every min and turn the inverter on/off based on the modbus SOC value.

Do Phoenix inverters communicate like the Multiplus? Modbus?

That would be really easy IMO.

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This might be an idea.

They comunicate via VE.Direct, is there documentation about how to comunicate with VE.Direct devices from the shell? Ill take a look into this.



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