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Kevin Pearson asked

Adding second Multiplus on Boat Split 30A Panel

I have a boat with two 30A 120V power feeds. Currently, I have the first shore power feed going directly into a Victron Multiplus whos output feeds the left side of the breaker pannel. I am now interested in upgrading my batteries and adding a second inverter to be feed the second (right side) breaker panel. I have read the forums for countless hours but cannot seem to find answers to some of my questions, and hope someone might be able to help.

I understand I would configure these inverters as "split phase" and configure them to switch independantly when I initially set them up. My boat will always connect to the same shore power connection and I know that the two power inputs will always be 180deg out of phase. The two 30a outlets are connected to two 230a GFCI circuit breakers that are physically next to each other on the breaker panel.

  • It appears that I will need to purchase 2 new Multiplusses becasue since my current unit is about 6 years old, there would be no way to get a "matching" inverter. Am I correct with this?
  • My marina's wiring has some problems and the GFCI breakers randomly trip at least once every couple of months (even if nothing is connected to them and outlets are sealed weather tight). This cannot be avoided and they will not fix it. With that being said, what is the behavior if the MASTER inverter loses power while the SLAVE inverter is still being fed with input power? Will the group allow the SLAVE inverter's input to stay connected, or will it disconnect because it is not 180deg out of phase with the non-existant MASTER? Will the batteries charge using the SLAVE inverter only? Will my GX control panel be able to detect this condition and report the situation to the online portal so I can detect this condition and take action?
  • I am planning on using a REC BMS and a DIY lithium battery bank. Does the victron system have any trouble working with two inverters in a split phase configuration using a third party rec bms?
  • If i set the input current limit on the GX to 30a, does that tell the pair of inverters that they are allowed to draw 30amps each, or would that tell them they both can draw 30 amps total?
  • On the GX control panel, does the information reflected on the status screen show the sum of both the inverter's outputs and inputs? Is there any way to see what each one is doing via the status pages?
  • My boat also has a generator wtih a split phase 240v output connected to a pair of large DPDT relays as a transfer switch. What happens if both shore power and generator power sources are energized, and the transfer relay activates while the generator and the two shore power connections happen to be completley 180degrees out of phase (or sync)? Not sure how many miliseconds the relay is "disconnected" while switching over, but can the inputs of the victron inverter handle this siutation? I have gone out of my way to make sure this didn't happen with my single inverter, but would like to know if this situation would cause a problem?

I was pretty excited when I learned about the 120v x 2 models that were offered, but then quickly bummed that they only came in 3000VA configuations.


Thank you so much in advance for any help on this.

split phase
2 |3000

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