Multiplus's in SplitPhase (Master/Slave) w/ Neutral Forming Transformer on EnPhase

[LikeWithMike]

I have a EnPhase system which operates at 240v L to L and when it goes off grid, it has a neutral forming transfer which gives me my L1/L2 to N of 120v. I'm adding an Victron setup to my existing setup and was wondering if having two Multiplus's (Master/Slave) for SplitPhase setup will pair fine with the existing neutral forming transformer. Alternative is to do a 230v Victron and run at 240v/60Hz which basically will be the same as the Enphase Micros run since they don't have neutrals natively.

Can two 120v multiplus's in a split phase setup get harmed with a neutral forming transfer?

 

[solar8484]

Do you already have the Victron inverters? The 2 120V Victron config can work but you might get significant circulating neutral current. Better to turn off the breaker for the neutral forming transformer in the combiner.

 

[B-ManFX4]

I run two MultiPlus 3000 units in split phase in my RV. I run their output into a Victron Autotransformer (32A model) to provide load balancing between the units.

 

[LikeWithMike]

Do you already have the Victron inverters? The 2 120V Victron config can work but you might get significant circulating neutral current. Better to turn off the breaker for the neutral forming transformer in the combiner.

I don't have the inverters yet, on the fence for 2x 120v vs 1x 230v (To run at 240v/60hz)...
I have the rest of the victron gear, for example

attached is a screen shot of my currently L1 / L2 loans and when I realized is my EnPhase system when exporting to grid and charging the Encharge batteries, aims for 0w Export, but in reality Victron meter when installed on the meter wires shows +/- say 50w (Total) and phase L1 would read say -475w and L2 would read +475w because the utility poles split phase transform is acting as the neutral forming transformer when grid tied. When off grid, the EnPhase SmartSwitch/ATS/Relays kill grid and enable the neutral forming transfer inside the smart switch to balance neutrals still since all Enphase micros are spitting out 240 L/L technically.


This leads me to the 230v Victrons because I feel it will better fit/match my existing EnPhase setup (See PDF for the two layouts) and technically work flawlessly on/off grid. For simplicity i will likely have 1 of the 4 relays off the EnPhase Smart switch kill the Victron Multiplus's when in off grid, just so I don't have to worry about anything and the Victron will be cycling the batteries much more than the enphase setup too since i'll have controls set for grid export/charges. Later this year will likely be adding 30 panels on a Victron MPPT charge controller to pipe more juice into the batteries too.

 

[solar8484]

In case you are still wondering, Multiplus 230V with appropriate settings also works fine with an external autotransformer.