Victron Multiplus II 3100 DIY install

Nice! I’ve decided to go with the 24/3000/70-50 2x120. I think I’ve got everything figured out now, except to figure out where to wire in the 24 to 12 vdc converter . . . . I’m guessing that the Victron Converter will be outputting 24 VDC to Lynx distributor so from there I would wire in the 24 to 12 converter to the DC fuse panel.

You will grab fused 24v feed from the Lynx (or whatever bus bar you decide to use) if you are installing that. Then wire the 12v to the bus bar on the left side of the front compartment. You can get a ground anywhere on the chassis for the 12v or overhead is negative near the shunt.

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The hydraulics motor pulls 800 watts with 12 volts (67 amps) and is originally wired to the Master Disconnect Switch so I will need to move the load to somewhere on the 12v side of the converter and make sure the converter delivers enough amps. Other than that I think all of the other 12v lines will be on the other side of the converter… . Orion IP67 24/12 70A Converter ~ Current Connected
looks like it will provide enough amps

This is a good video on the discussion between 12v, 24v, and 48v. I agree with @tkostansek and @ThreatLevelMidnight that 24v or 48v is the way to go. If you are going Victron Multiplus route the sweet spot is 24v right now. Once Victron has a 48v step down DC charger it then it would make more sense to go 48v.

@ThreatLevelMidnight how are you going to tie all that wiring together? I believe 6awg can’t use wire nuts for more than 2 pair.

Am I seeing 2 pairs of wire coming out of that box on the bottom to each inverter? Love to see an electrical diagram on how you did this.

Just wondering why two units over the 2x120 Multiplus?

Complicated question, I chose 48v because it matches most of the components I use in a sticks and bricks home so this give me some common components.

I wouldn’t touch 12v unless you will only ever install a single 3000VA inverter aka 2 x 120 model of the Victron Multiplus II. The sweet spot is 24v in Victronland till they make a better smart DC charger.

I have electronics and dry camp a ton in which I am turning on and off a generator and didn’t want things rebooting, so I needed normal 1 x 120 Multiplus on each leg to give me the UPS functionality.

If someone wanted me to help them do an install today I would weight the pros and cons of a pair of 2 x 120’s which only come right now in 12/24v. You loose UPS functionality one of the two legs of 50a service. What you gain is effectively is a pair of inverter/chargers that can be combined so you have the full 6000VA across both legs. The only way I can load share from a pair of mine is to add the autotransformer so I am stuck at 3000VA per leg.

The other issue is I love the autotransformer but we run into another issue. In a RV application campground can now be built (and some utilities are mandating) they run off 2 legs of a 3-phase grid. If you go to a park with 3-phase the output from L1-N & L2-N is 120v just like we have always had. However, L1-L2 will be 208v not 240v.

Since basically no mass produced RV has 240v appliances (and one niche ones has 208v compatible appliances) this is not a problem. The autotransformer will cause a problem in this scenario. It’s not intelligent the winding simply take the input voltage measured across L1-L2 and cut that in 1/2 bit is able to shift the amps from one leg to the other. So if the input as measured across the legs is 208v the output measured across L1-L2 will be 104v or in brownout territory.

What I have seen is people do one of two things 1) Make a special adapter and when they encounter a park with 3-phase power they just power one leg thus one inverter. This is the opposite of a normal dog bone which bridges both legs. In a Model Z a single 50a shore power more than enough btw. 2) I have seen people put switch before the main to flip from 240v to 208v depending on the park, again just powering one Multiplus. 3) In Victronland they make profiles and apply either a split or parallel configuration depending on the park they are going too.

The 24v Multiplus 2x120 really makes it far more plug and play you don’t have to deal with the above. Plus the room in the front bay is tight for a 3rd big transformer so I would probably put autotransformer in the wet bay. Then it comes to DC to DC and if you keep a buffer 12v battery you can get a proper Orion Smart charger from 24v to 12v or a pair of 24v to 12v converts which is more then enough to run all the 12v appliances.

For wiring question, I will make a diagram in the interest of sharing with the community. Would a parts list for 48v and 24v options be helpful?

I ran mine from shore through the wet bay to the surge protector. Then a net new 6/3 followed the factory wiring on the underbelly on the drivers side and came out the same hole into the from compartment terminating in a box large enough in sq inches of volume to support all the polaris connectors I used. From that box you will see in the photo I have 4x sets of 6/2 running to each Multiplus. I combine the input grounds and neutrals (and output separately) what is left is L1 in/out (black) and L2 in/out (red). Diagram will make this clear on the AC side.

Then I bridged with a small piece of 6/3 from the output of this box to the factory generator prep which brings power all the way back to the wet bay. The former cable that came from the inlet plug ties into that box.

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I’m jumping in here with an observation. We just sold our Winnebago motorhome and bought the Brinkley. With Winnebago you can download wiring diagrams that are incredibly detailed. I was dismayed to find we cannot get those. I am pretty glad we are having some pros with Brinkley solar installs doing ours.

Yup I contacted Brinkley and inquired about wiring diagrams. Their answer was “we don’t get involved in 3rd party modifications”. I said its for me I am doing it myself self. Their answer was sorry no wiring info available. Really? Very disappointing.