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tobyfw avatar image
tobyfw asked

PV on AC-IN with ESS: Two ET112 needed?

Hello, I am already running an ESS with DC-coupled PV (MPPT chargerrs) and AC-coupled PV (Fronius) on AC-Out. One-phase system with Quattro II 48/5000.

To add more AC-coupled PV beyond the 1:1 rule, I plan to connect a Hoymiles micro-inverter to AC-IN, in front of the Quattro. There will be _no loads_ on the AC-IN. Just grid going to both micro-inverter and Quattro.

In such a setup, do I need one or two ET112? (Inverter on AC-IN should be able to charge batteries, when other inverters do not)?

If one ET112 is sufficient, should it be wired and set up as Grid Meter, or as PV meter? I would prefer to see the PV on AC-IN labeled as "PV inverter" on the Dashboard, but it is not a must.

Thank you


ESSEnergy MeterAC PV Coupling
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3 Answers
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sharpener answered ·

Depends how the grid connection is metered at the moment. If using the internal sensor you will need an external sensor before the PV connection, but a CT will be cheaper and faster responding than an ET112.

For the new PV you need to connect an ET112 in series, in Settings|Energy Meters set the Role as PV Meter and Position as AC In then it should show up as you want.

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Stan avatar image
Stan answered ·

You can use one ET340 instead of two ET112. You can measure one phase on phase 1 and PV inverter on phase 2.

I have it like this in my system without any problem. One ET340 is cheaper than two ET112.

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sharpener answered ·

I have not got one installed (as I have nothing on AC-In) but AIUI you can connect the https://www.victronenergy.com/accessories/current-transformer-for-multiplus-ii to the CT input. The version you need will depend on how old your inverter is, the older units have a (none too reliable) audio jack which automatically switches the internal CT out of circuit but the later ones with the wire end I have read you need to change a jumper link. Check what will suit your Quattro.

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