Victron Multiplus 12/3000Va/120-50 2x120 - Install Testing Issues

NascarGuy

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Jun 10, 2021
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Today I spent the first half of my day installing a Victron 12v/3000va/2x120 in my 2017 Thor Outlaw 38RE and the second half of the day trying to get it to work properly, to no avail. I am hoping someone smarter than I am can assist. Here is the situation.

Installed the Multiplus-II and configured it to run with my 600Ah of Dakota lithiums, no issue there. It will roll from inverting, charging, etc; no issue there. The issue comes into play when I am running on generator power (which is an Onan gas 5500). The Multiplus is only using one of the 30a legs off the generator for power. When running the two rooftop AC units and the power on the AC-IN side gets to about 3900W it trips the circuit breaker on the generator(basically when supply is less than the demand). The odd part is that the breaker it is tripping is not the 30a that is running the AC units. It is tripping the opposite leg. I have trips moving the AC units to separate circuits on the circuit breaker panel in the coach and no change. I can see that both the L1 and L2 legs have available power but it is only using one 30a. It will show only L1 on the AC-IN side and L1 & L2 on the AC-OUT side.
I googled the crap out of the issue and found that many have had success disabling the "Ground Relay" feature in the VictronConnect app; did that and no change. I have tried replacing the 2 30A breakers on the generator thinking maybe I had weak breakers; no change. I have tried flipping the legs around the MP and it trips the opposite breaker.

I am at a total loss here. Basically, I went from having 2 x 30a while running on the generator to have only one 30a circuit available. I've gone thru all the settings in VictronConnect and VEConnect3 but see nothing that would control the L1 / L2 legs on the AC-IN side.

Suggestions? I am open to anything at this point.
 

carlrx7

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Dec 21, 2020
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As i understand it, the multiplus will disconnect L2 input if 240v is not present, as it ignores (what it thinks is a bootlegged L2 connections.

I plan on installing a manual 50A switch to bypass the multiplus completely for emergency/ hardware issues.
 

RipNC

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Oct 22, 2021
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Nascarguy,
Did you resolve this yet? Carlrx7 is correct, the unit drops L2 if it is in phase with L1 - the Onan 5500 is a 120v generator with either 2 - 30A breakers or a 20A and a 30A. Mine has 2 - 30A so my plan is to parallel wire them to L1, I may have to add a jumper to L2 for my ATS to work (unknown). This way the entire 46A of available power from the Onan will be available on L1 input. Probably be a couple weeks before I make my wiring change at the ATS.

Do you get a load hum from your MP2 (most likely the charger) all the time? Mine is much quieter inverting (no AC input).
 

cinergi

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Aug 9, 2020
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Most Onan's that have 2 legs are 2 120v legs that are not out of phase with each other, thus providing 240 split phase. The inverter sees this and won't connect.
I don't know that you can parallel the two outputs of the generator to get a single "60" amp supply. That would require some research.
I don't have the MP2 and I don't really know it; ask your Victron reseller for assistance on how to connect to a supply where both L1 and L2 are the same phase (from the generator). Hopefully it's possible.
Please also make sure your Victron is still set to bond neutral and ground (the ground relay setting) when disconnected from shore. This is extremely important from a safety/shock perspective.
 

RipNC

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Oct 22, 2021
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My Victron reseller suggested the parallel wiring. My issue is whether it will work correctly with my ATS which has an EMS board. I ass/u/me it will work (with a jumper to L2) since it works with L1/L2 in phase now. Yes, my ground relay is on.
 

Grabcon

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Nov 19, 2020
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37
NascarGuy, did you ever get this issue resolved? I have a 2007 Damon Outlaw 3611 and am getting ready to pull the trigger and buy one of the Victron 12v/3000va/2x120 inverters. But want to make sure that this is the right move.
 
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