Victron multiplus II 48/5000 vs ATS

DIY
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1

Hello,

maybe the community can help me with the following situation.

the Victron is a Multiplus II 48/5000 with two Fronius Primo 6K, one on grid, one on micro grid limited to 5K.

I want to use an ATS to put the loads on the AC OUT1 of the Multiplus only in case of grid failure. Reason for this is that the loads are 3kW-4kW almost constant and it drives the Multiplus hard, fans on all the time.

I want to keep the loads on the grid and switch to the Multiplus AC OUT1 only when the grid fails.

Do you think the schematic below is functional ?

Thank you,

Geo

image
image1177Ă—860 75.7 KB

2

Why use an external transfer switch when the Multi has one built in?
Typically that would only need to be used when the Multi fails…

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3

The person who put this setup together applied the 1:1 rule, meaning the rating of the PV inverter matches the rating of the MultiPlus inverter. For this configuration, you will need a 10 kW or 15 kW inverter.

Additionally, you might consider replacing the AC output connected to the Fronius with an MPPT, such as the 450/100. I have a 450/100 and two 5000 W grid-tied inverters. I also installed a transfer switch to connect one of the PV inverters to the AC output in case of a power outage.

4

Once the batteries are full, there should be no load on the Multi when the grid is connected…