I am planning to purchase 2 Multiplus II (12v 3000W 120v units) and staking them in parallel. Then connecting an Autotransformer to step up to 240V. Most of my loads will be 120v however I have a 240v motor for a compressor that I want to use occasionally. I’m trying to figure out how I can set u…

Setting up split-phase or parallel single phase systems is done in VEConfigure or VictronConnect. The output neutrals of the multiplus-es need to be combined on a Neutral busbar. One unit is designated L1, and the other L2. That’s pretty much it. [IMG_7574] Here’s a setup video: [Programm…

For the compressor motor with the VFD. The VFD will convert single phase 240v to 3 phase 240v.

How big is this 3ph motor? It’s pretty common practice around these parts to use a vfd to drive a 3ph motor from a single phase source but it is one of the least efficient ways to achieve 3ph power. The auto transformer will limit your 240v current to 28a(32 peak) even if you go with the 100a mod…

Dave, Thank you for the prompt reply. There is another boat owner that did this without the Autotransformer using 1 multiplus unit running a 3ph 2.0HP (1.5KW) motor and a VFD. I haven’t been able to get a reply on how he configured his Multiplus, but I did email with a tech from united automation…

Be mindful of the N>G bond control since the common method of transferring N>G relay control to the AT from the I/C is fine for the loads being served by the output of the AT. If the paralleled Multis are also supplying a load center, that load center will not have an upstream N>G at its source.

There are a few configuration options I see. I’m going to assume the VFD takes 240V and produces the proper 3-phase for your motor. I’m very concerned you are trying to do this with a 12V system. The surge current on the batteries will be immense when starting that motor, even with the VFD. Putt…

Doing split phase 240 to feed the vfd is a better method imo than using a transformer Though it is only 2400w 240v/ 4800w 120v

Rick Thanks for your reply! Yes I was thinking 240v single phase to 240v 3 phas for the VFD My battery bank will be 920ah LiFePo4 (I can add more, but don’t think it’s necessary). Another guy used 1 3Kva Multiplus with 600ah LiFePo4 battery bank to a VFD running a 1.5kw 2.0HP 3 phase motor, and i…

Any suggestions on single phase vs 3 phase for a 240v electric motor off this split phase set up?

Setting up 2 stacked Multiplus II units with Autotransformer for 240V

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chriscatt (cattmarine) 27 April 2025 19:40 6

Charlie,
I don’t fully understand the ramifications of that. Would it work better with 1 5kva Quattro compared with 2 mulits in parallel? Or what about using 2 muliti’s connected as 240v then stepping down for load center that requires 120v

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Setting up 2 stacked Multiplus II units with Autotransformer for 240V

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