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gutzpowers avatar image
gutzpowers asked

Adding to an existing MPII 240/120v - 48v Split Phase System

If two MPIIs 3kva 120s are already setup in 240/120 split phase can two more be added to the existing system to double the power, basically four MPIIs running split phase to a single critical load panel? Looking at future growth.

Multiplus-II
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Alexandra avatar image Alexandra ♦ commented ·

You will have less headcahes if you just bought bigger units and replaced the setup. You will also need to add more battery as well. And uograde cable size if you did not already start larger.

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Mike Dorsett avatar image
Mike Dorsett answered ·

yes that would work, with above comment noted. inverters need to be the same madel and firmware version though. Care would be needed in setting up and correct wiring.

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gutzpowers avatar image gutzpowers commented ·

@Mike Dorsett

So 4 MPIIs can be setup in split phase. Do you happen to have any links on a setup like this? Acknowledge the guidance above on replacing and the wiring. Almost see this as a 2s2p setup and yes must be very careful with the ac-in and ac-out to make sure everything is aligned properly.

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Mike Dorsett avatar image Mike Dorsett gutzpowers commented ·
The VE bus spec says that up to 6 multi's can be used in a setup, so using VE configure to allocate 4 to a 2 parallel- split phase system should work.

Important:

Use equal length and size battery conductors to the busbars. Do not oversize the cables as impedance here helps to balance the power between the inverters.

Use equal lengths of cable on the AC side for the same reason.

Sorry I don't have any links, but have run multi's in parallel before (single phase, not split) with no issues.


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