Question about rule 1.0 and export limit in AC-coupling

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newbiesolarenthusiast asked Mar 14, '22

Question about rule 1.0 and export limit in AC-coupling

Hello,

Because of reliability issues with the network in my area, I have installed an off-grid solar system (Multiplus ii 5kW + MPPT with 3kW worh of solar panels and 200Ah AGM batteries @ 48V). I'm now looking into expanding my installation with AC-coupling using a Fronius Primo 3.0-1 and ~3kW solar panels.

According to the Victron documentation about AC-coupling I have an undesized battery for this configuration (If I understand correctly, I need at least 300Ah for what I'm trying to do). I don't want to invest in more battery capacity as it's enough for my needs and the upgrade would be quite pricey. I was thinking of using a smart meter and limit the export of the Fronius to 0W. Would this solve my problems? Also, where should I place the smart meter, on the AC-in of the Multiplus or the AC-out?

AC PV Coupling

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Answer 1 · 2022-03-15T13:50:24Z

newbiesolarenthusiast answered · Mar 15, 2022 at 01:50 PM

I've found that the Fronius inverter should stop power feedback in less that 5 seconds when using a smart meter. This should be enough to not damage the batteries, right? Does anyone have any experience with this?

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Answer 2 · 2022-03-15T14:41:43Z

ponzoa answered · Mar 15, 2022 at 02:41 PM

Hi, I'm using AC Coupled Fronius Primo in an ESS setup which should be the same for what 1.0 rule refers to and I don't use the Fronius Meter as the info goes to the inverter & GX device vía modbus. In my case it's a Multiplus II 48/10000 and a Fronius Primo 8.2-1. Works wonderfully, and without a meter. I also have some Victron MPPT's feeding my batteries. The DC coupled side doesn't need to respect the 1.0 rule.

You do have to use the assistant in VE Configure though and ensure your GX finds the Fronius on the same network.

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newbiesolarenthusiast commented · Mar 15, 2022 at 05:06 PM

What battery type and size do you have? lithium or lead acid and what voltage and Ah

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Answer 3 · 2022-03-18T11:38:44Z

newbiesolarenthusiast answered · Mar 18, 2022 at 11:38 AM

I just wanted to clarify, I was asking about using a Fronius Smart Meter to limit the export, NOT one of the Victron Energy Meters. I would prefer doing it this way because I don't have a GX device.

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nickdb ♦♦ commented · Mar 18, 2022 at 11:45 AM

I don't believe this setup will work properly without a GX.

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