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hoeken avatar image
hoeken asked

DVCC with two different inverters + Cerbo + Lynx Smart BMS

I have a sailboat with a lithium battery system, cerbo, lynx smart bms, a 5000w 230v Quattro and a separate 5000w 120v Quattro. The 230v Quattro is connected to the cerbo directly via VE.Bus. The 120v Quattro is connected to the Cerbo via a USB MK3. The system is working well and I can see and control both inverters from the Cerbo.

I'm trying to set it up so that both inverters shut off when the battery gets to a certain SOC (20%). I found that in the Lynx Smart BMS I can set the discharge floor with Victron Connect and that will disable the ATD. The 230v quattro that is connected directly via VE.Bus turns on and off as expected, but the 120v quattro over the USB MK3 is not turning on or off.

Are there any settings I need to change to get the 2nd inverter to follow the DVCC instructions from the Cerbo? I've looked around quite a bit and nothing is jumping out at me.

cerbo gxDVCClynx bms
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nickdb answered ·

You can't control multiple, independent inverters with a single GX. It is not designed to work that way. You will only have partial functionality and DVCC will not work in that scenario.

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hoeken avatar image hoeken commented ·
This seems like a strange oversight on Victron's part. Do you know what the technical reason behind it is? I don't know how the code underneath the hood runs, but it seems like it should be a pretty straightforward software change. Instead of hardcoding as a single inverter, loop through any available inverters / VE.Bus connections when sending ATC and ATD.


To be clear, they are separate inverters, on separate VE.Bus'es. It is already working for me to see both of them on the Cerbo, as well as control on/off/charger state through the cerbo for both. So its definitely possible to do this, but whether it is a software development priority is a different question.

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nickdb avatar image nickdb ♦♦ hoeken commented ·

The GX and DVCC can only work with a single logical system of devices on a shared VEBUS, configured as 3phase/Parallel. These inverters will appear as one logical system, but with multiple phases (in a 3 phase setup).

Parallel systems are in a master/slave configuration.

This is all fairly clear from the docs.

There is a lot that goes on in the coordination of a multi-inverter setup, trying to do this reliably across independent systems is likely more complex than it appears.

It is a bit of a niche requirement.



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semlohnhoj avatar image semlohnhoj hoeken commented ·

I suspect that part of the reason this isn't possible at present is that most of the internal registers for the state of an inverter are mapped to specific variables ( in the case of Modbus, to specific addresses) so there is no way to uniquely identify the units for some features. I've got this issue with a Multi RS Solar and an Inverter RS Smart. The Modbus address are identical. I'm hoping it gives them unique identities in NodeRed but I'm not confident.

I haven't even started trying to work this out as the second inverter hasn't arrived yet but as @nickdb has suggested, it's probably a second instance of Venus on a Raspberry Pi if you want full access. No idea how you'd get the DVCC working at that point though.

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