question

martghh avatar image

Equivalent AC (PV) Inverter support on SMA as on Fronius systems

Hi,


given the sunspec (modbus) support the current 3p SMAs have, could i expect an equivalent set of features and integration options as Fronius systems have already in the past ?

Venus OSoffgridFronius
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2 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @martghh,

Some, but not all.

This documentation describes it - https://www.victronenergy.com/live/ccgx:ccgx_sma

3 comments
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Hi Guy,

thanks for the answer - i've already found that document - following that i would like to understand if the current differences are because of basic technical contrains (i.e. sunspec implemented by SMA is not covering all requirements, etc...) or just 'integration work to be done' in order to achieve comparable features ?

best regards,

Martin

I don’t know the answer to that one.

The Victron and Fronius partnership on compatibility and support is very good from a technology, and company culture perspective.

They are the preferred AC PV inverter to use with Victron. So at what level the difference is (low level limitation, or development work) may perhaps be a distinction without a practical difference.

martghh avatar image martghh Guy Stewart (Victron Community Manager) ♦♦ ·

Hi Guy,

got the message ;-) while reading all documentation around this topic, may i take the chance for a remaining question - my current understanding of the 'zero feed in' feature for the Fronius systems - which is the main difference to SMA - is that for ESS config and AC-in active, i could control the solar power so that charge power plus local consumption equals to solar output (zero net balance). If AC-in dropped (entering off-grid state) the all solar power control is based on frequency shifting, correct ? If that understanding is wrong, where could i find all that 'nasty details' or even examples of that ?

best regards,

Martin

robert-campbell avatar image
robert-campbell answered ·

I've been thinking long&hard about integrating my SMA inverters to achieve zero-feed in for the grid. My thinking currently is as follows:
1. Get node-red and set up a Fronius inverter (virtually) using node-red server https://flows.nodered.org/node/node-red-contrib-modbus make it give responses that are 'Fronius Compatible' use 'tcpdump' or something similar to work out what the GX is requesting. You can also use the modbus documents from Fronius to 'reverse-engineer' that modbus server.
2. map the power-limitation functions that the Fronius supports to the SMA modbus implementation using node-red functions to mutate the data into the correct format and get the modbus client to write values to the SMA via modbus. Hopefully/presumably the Fronius supports a wattage limitation, my SMA (tripower) is able to do that too.


If we create a 'catalogue' of these node-red functions, we could support other inverters too, not just SMA (even via a 'spiffy' web-interface, this can be built quite easily in node-red). And you could use HTTP APIs or other methods to control the power on these inverters. I guess you could even offer it as a 'service' on a raspberry pi device or something similar.


I realise this is not for everyone and that Victron might even remove this reply as being 'not great' for their business model/deal with Fronius. On the other side, it offers a way to integrate these other inverters in a cool/useful way to Victron infrastructure, making it better/nicer to be integrated with other brands of inverters.



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