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harry-75 avatar image
harry-75 asked

ac coupled using sunnyboy 4000tl and fronius ac inverters

Hi I am looking at going off grid with victron quatro inverter chargers i currently have two solar arrays one is 4.5 kw with a sunnyboy 4000tl inverter and the other is a 6.5 kw with a fronius 5 kw inverter i was wondering can these inverters be used in an ac coupled system off grid using a quatro 15000va and a 10000 va i will also have approx 64 kwh 48 v agm battery bank

AC PV Coupling
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Mike Dorsett avatar image
Mike Dorsett answered ·

Yes, but you will need to be able to control the output power from the inverters when the battery is fully charged...Also, the peak PV power must not exceed the Quatro's power. Also you should note that The inverters - if used in the same AC system need to be the same model and firmware version...

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harry-75 avatar image harry-75 commented ·

thank you is there an external way of regulating inverter out put i havnt came across anything just yet.

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shaneyake answered ·

https://www.victronenergy.com/live/ac_coupling:start
Is a good place to start.
The way we control other inverters is through frequency shifting.
This is setup when you configure the inverter via VE.Config.
It also might need to be turned on in your PV inverters with the same settings in both.
Here is how to setup the Fronius inverter. you can apple same frequency settings to Sunnyboy.
https://www.victronenergy.com/live/ac_coupling:fronius

4000+6500 = 10 500va which is a little more than the Quattro 10kva can do but would probably be fine. 15kva would work well.

If you are trying to use multiple Victron inverters in parallel they need to be same model and hardware version. You can not mix 10kva and 15kva.

I would recommend against AGM batteries if you can avoid them. It would be match better to use a CAN managed battery like Pylontech, BYD, Freedomwon, etc if you can.

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harry-75 answered ·

thanks for the insight the inverters will be running of the same batterie banks but the 15kva will be wired to the house the 10kva will be to the shed and the pv arrays wired 4.5 to 15 kva and 6.6 to the 10 kva there for they will back feed and charge the same battery bank when the ac coupling allows it ( my thoughts any way) i will have to look into how to do frequencie shifting on the sunny boy as i have not been able to locate any info on this unit to do with frequency shifting

regards and thanks again

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shaneyake avatar image shaneyake commented ·
Do you already have the 10kva and 15kva inverter? If you don't I would recommend that you You get 2 of the same units. It isn't great to have 2 separate systems on one battery pack if you can avoid it. You can then parallel them and have the combined output of both. It also makes monitoring easier as you only need 1 Cerbo GX.
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