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olly12383 avatar image
olly12383 asked

Multiplus - modbus - grid tie solar 3ph - use spare energy

Hi, I have a house with a 4kW GT system on FIT on phase A

I have added a 12kW array which I am planning to split over phase B and C.

I want to use a multiplus II as a smart inverter/charger from a lithium battery to store excess energy from any phase.

My supplier meter is net metering (non smart). So what I (think I) need is my own net metering meter which talks to the Multiplus and tells it to charge or discharge the battery to keep the import/export at zero. However this will only be pulling off one phase. This is why I need the external meter. If I am exporting 1kW on phase B and C (for example), with no import, but the Multiplus is on phase A, it can still import 2kW on phase A with no supplier charges.

I have researched Modbus meters but I just wondered if anyone had done anything similar - presumably I need an interface between the Modbus and the Multiplus to convert Net Export Power into Victron charge now Power.

I will have a zappi car charger and a DHW store system to soak up the excess energy. Ideally this would be priority order

1. Car (if present)

2. House batt

3. DHW cylinder

4. Export.

Although I would be willing to always do House first if that is less complicated (the zappi and DHW system will communicate internally but I don't know if they would communicate with the Victron).

I believe delays can be programmed such that the Victron could have a shorter delay on start up than the Zappi which would ensure the house batt gets priority over the car.

Of course as the car isn't always there I thought that would be best if the car got first dibs as hopefully if its a sunny day the house would get a chance later after the car leaves.

I should be good for producing approaching 16000kWh per year with this system (the 1year old original 4kW array made close to 4000 in a year and the 12kW array is less shaded)

My background is Marine - off grid so use a lot of Victron products. I have used R pi a bit so I guess this or Arduino could maybe be a useful interface if there isn't a premade solution available.

Thanks in advance

Olly

ESSEnergy MeterModbus TCPgridsolar
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2 Answers
dayandnight avatar image
dayandnight answered ·

Hi @olly12383,

I am wondering about your question why nobody did answer it. I think what are you asking about is a typical Victron ESS system. When I am right it is rather simply to full fill your wishes. You need a Gavazzi energy meter, three Multiplus-II and of course batteries. Such an installation should be done by professional Victron reseller who has experience to do such a system. It is complex but not as doing a journey to the moon. ;-)

Read the above linked documents and when you need more details or you do have question, come back and ask.

DayAndNight

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catraz avatar image
catraz answered ·

I’m also interested in this question. Can excess energy from a parallel PV inverter (on AC in) be used by the ESS to charge the batteries? Is this possible using the AC out connection?

‘Thanks

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dayandnight avatar image dayandnight commented ·

Hello @Catraz,

"parallel PV inverter (on AC in)" Do you mean a PV system which is connected to the grid? In case yes and based on this little information the answer is YES - just have a look into the Victrons ESS system.

DayAndNight

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