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Tesla Powerwall AC coupled with Victron Quattro

A similar question was asked to this previously but never really answered (lots of alternatives suggested but that was it!)

In an off-grid system, can a series of Tesla Powerwalls be AC coupled with a Victron Quattro.

In my specific case I'm running an AC/DC coupled system already with BYD batteries a 10KVA Quatrro, 7kW Fronius and small Victron MPPT.

Rationale: the price of Tesla Powerwalls has now dropped to be cheaper than BYDs - especially if you acknowledge they include an integral DC/AC inverter... I need to double the size of my system in the next 12 months.

Can these systems operate in a sensible fashion together...?

MultiPlus Quattro Inverter Charger
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1 Answer
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Paul B answered ·

I dont think that Victron would have tested that scenario, but if you are thinking of using the power wall as the AC1 input to the quattro then the quattro would export back to the powerwall if there was a excess in power, the big question is what happens when the power wall is FULL and thus does not want any more power and how does the quattro know to stop exporting when the power wall say stop, this sort of question is very hard to answer and is a more of a trial and error setup so be very careful here as you could get your fingers /pocket burnt very easily, I would suspect that you would be better off to talking to your Local Victron Installer and see if they are willing or capable to be of help. or the Tesla power wall installer,

I myself would not like to be involved in that sort of setup because if something happened and damage was done to the powerwall the quattro or the Byd batteries, you would I suspect want to pass the blame. this to me is a experimental setup and as such is to be done all at your own risk.

well thats my thoughts and there maybe others out there who have a better answer than me

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I’ll +1 that... I know the Quattro and Powerwalls can work together in this arrangement *on grid*... but as the OP specifically said Off Grid this is where the problem comes exactly as you described... when it’s “full” the Quattro has to stop exporting... or in reality the solar chargers have to back off what they are producing for the Quattro... now I do believe the Powerwall 2 has at least one relay output that can be programmed (eg for generator startup).. (I have no personal experience of them, so going on third party knowledge here) so in theory that could be used with the solar chargers “remote on/off” terminals to turn off one or more of the solar chargers when the system is full...

Actually thinking about it.. the TP2 can do non export... so if they are downstream of the Quattro it *should* work like a normal on grid system where the Quattro is “the grid”... but Defo would need to confirm this with a Tesla and Victron professional.

The Fronius inverter has the same challenge: when to shut down the solar panels when the battery is full. The quattro achieves this by shifting the frequency to 52Hz...

I don't know if the Tesla PW2 can interpret this frequency shift command...?

If the PW is downstream of the Quattro it won’t be exporting so the PW will not need to frequency shift... it’ll take what it needs and just stop taking it (ie seen load will go down) the Quattro will take all it needs until the batteries are full then it will frequency shift to control the Fronius... the only question is what will the PW do if it sees 52Hz... will it shut off the input and continue supplying the loads connected to it in an attempt to “protect” the equipment? Again.. talk to both you local tesla and Victron professionals for th best advice... I’m not a professional in that respect, I’m just an engineer.