Multiplus Chassis Wiring

[caymaanedge]

Going from a Magnum MS2812 to the Victron Multiplus II 2x120v.
It appears that currently L1 runs to the inverter and then to part of the 120v split us panel, and L2 goes directly to the second part of the split bus 120v panel. So basically only items on the L1 side of the 120v panel will work if not plugged into shore power or on inverter.

So…do I need to run new wiring from the existing transfer switch to the Multiplus to accommodate L1 & L2 as well as from the inverter to the 120v panel? TIA

 

[sneil]

I have a similar setup in my RV. From shore power/ATS run L1, L2, N & G to the Multiplus AC IN. From the Multiplus AC Out, run the L1, L2, N & G to the circuit panel. This allows the Multiplus to supply inverter power to both legs of the panel.

 

[kenryan]

Can't help you, but would like to ask why you are switching. I just bought a 2812, having had great success with Magnum inverters for many years. But I haven't installed the new one yet. Wondering if their quality has declined over the years?

 

[caymaanedge]

Can't help you, but would like to ask why you are switching. I just bought a 2812, having had great success with Magnum inverters for many years. But I haven't installed the new one yet. Wondering if their quality has declined over the years?

I want to be able to run the entire coach off my inverter. I have a large Solar array and LifePO4 bank.

 

[corn18]

I have a similar setup in my RV. From shore power/ATS run L1, L2, N & G to the Multiplus AC IN. From the Multiplus AC Out, run the L1, L2, N & G to the circuit panel. This allows the Multiplus to supply inverter power to both legs of the panel.

Yup, this is why the MPII is such a great fit for 50A RVs.

50A shore power - everything gets power
30A shore power - everything gets power
Inverter only - everything gets power

The MPII sorts it all out and everything in the RV always gets power.

The other great feature is the power share. If you are on a 30A shore power connection and need a little extra, the MPII will supplement with the inverter. And even better, when you are on a genset, it will supplement the genset. Allows me to use a smaller 2000W genset to power my AC and residential fridge with a little help from the batteries. If not for the MPII, I would need a much larger 3kW genset.

 

[sneil]

Yup, this is why the MPII is such a great fit for 50A RVs.

50A shore power - everything gets power
30A shore power - everything gets power
Inverter only - everything gets power

The MPII sorts it all out and everything in the RV always gets power.

The other great feature is the power share. If you are on a 30A shore power connection and need a little extra, the MPII will supplement with the inverter. And even better, when you are on a genset, it will supplement the genset. Allows me to use a smaller 2000W genset to power my AC and residential fridge with a little help from the batteries. If not for the MPII, I would need a much larger 3kW genset.

I've been running the prior version of the MultiPlus 12/3000/120-50 120V along with the AM Solar smart phase selector to get power to both legs of the panel. Unfortunately the SPS died but I got a good deal on replacing the original Multiplus with the new 2 x 120 version which eliminates the need for the SPS. And still get all of the great features from the original with better power assist on both legs from the MPII.

 

[caymaanedge]

Thanks for the input. Clearly the new Multiplex is the way to go!

 

[bpal]

Our generator is putting out 50a in-phase (actually L1 & L2 in-phase up to combined 10kw). I have read where if L1 & L2 are in-phase the MPII will block incoming L2. Is that true?
I will have to figure out if my generator can be switched to output split-phase or a way to switch out the inverter when I want both legs of the generator and don't need my house battery charged. Has anyone else solved this?

 

[sneil]

Our generator is putting out 50a in-phase (actually L1 & L2 in-phase up to combined 10kw). I have read where if L1 & L2 are in-phase the MPII will block incoming L2. Is that true?
I will have to figure out if my generator can be switched to output split-phase or a way to switch out the inverter when I want both legs of the generator and don't need my house battery charged. Has anyone else solved this?

I believe that is correct with both legs being in phase, the MP II will reject the L2 input limiting it to using just L1.

Our generator is a Cummins 5500 which can output a total of about 45 amps. The generator has a 30A breaker for each line, so in reality I was only getting 30A through on L1. I wanted to be able to use the 45A if needed. I watch the Changing Lanes you tube channel and Chad came across the same limitation. He detailed his fix here by paralleling both generator outputs so it feeds 45A to L1 on the MP II. I did the same thing and am now able to use the full 45A from the generator.

Maybe this is an option you could look into as well depending on your generator.

 

[zulu]

Our generator is putting out 50a in-phase (actually L1 & L2 in-phase up to combined 10kw). I have read where if L1 & L2 are in-phase the MPII will block incoming L2. Is that true?
I will have to figure out if my generator can be switched to output split-phase or a way to switch out the inverter when I want both legs of the generator and don't need my house battery charged. Has anyone else solved this?

Yes, if your inverter is in-phase (like mine), then the Multiplus II will only "see" L1.

Solution for in-phase inverters only: combine generator L1 & L2 before they enter your transfer switch.

Here's a video about the process: Changing Lanes (@ 11:04)

 

[sinan]

Yup, this is why the MPII is such a great fit for 50A RVs.

50A shore power - everything gets power
30A shore power - everything gets power
Inverter only - everything gets power

The MPII sorts it all out and everything in the RV always gets power.

The other great feature is the power share. If you are on a 30A shore power connection and need a little extra, the MPII will supplement with the inverter. And even better, when you are on a genset, it will supplement the genset. Allows me to use a smaller 2000W genset to power my AC and residential fridge with a little help from the batteries. If not for the MPII, I would need a much larger 3kW genset.

Just FYI, the same can be done with the Magnum MSH-3012RV

 

[corn18]

Just FYI, the same can be done with the Magnum MSH-3012RV

Yup, I think there might be others as well. Sure makes it easy for us 50A RV types.

 

[bpal]

So I have convinced myself that the standard Multiplus will be better in my situation than the Multiplus II 120vx2. I have a 50A RV with shore power and a 10kw generator. The current setup is a Xantrex Prosine 2.5 that inverts and charges but has no pass through or boost. I already have a 2nd transfer switch in my RV which I can utilize. My biggest concern with the MPII is inability to use both legs of generator power. I don't expect to use the generator much with my solar installation but when I need it, I will need it.

Am I missing anything?

Multiplus - with 2nd transfer switch
Pros -

• Inverter -
  
  • Improves current install by powering all main L2 circuits in addition to subpanel circuits
    
    • Primarily Front A/C; Engine block heater;
  • Inverter boost on Main panel L2 + subpanel circuits (when linked to Inverter L1)
  • Can invert main panel L1 by connecting AC-2 Out with high SOC logic assistant (would require use of the existing 2nd transfer switch)

• 24v battery supply
• Generator 120v/50a fully powers both L1 & L2 (+ boost) in main panel and subpanel circuits
• Shore power 120v 15/20/20a powers both L1 & L2 (+boost) in main panel and subpanel circuits

Cons -
Have to manually manage load usage to not overload inverter (likely the same with all options)

Options

• Could swap Rear A/C and Engine block heater circuits to allow Rear A/C on inverter AC-1 Out (would allow both A/C on 15/20/30a shore power by utilizing inverter boost)

Multiplus II 2x120

Pros -

• Inverter -
  
  • Improves current install by powering all main L2 in addition to subpanel circuits
    
    • Primarily Front A/C; Engine block heater;
    • Inverter boost on Main panel L2 + subpanel circuits (when linked to Inverter L1)
    • Inverter power of Main panel L1

• Eliminates 2nd transfer switch
• Shore power 50a split phase (240v capable) powers Main panel L1 and L2 and subpanel
• 24v battery supply

Cons -

• Generator in-phase power L2 is blocked so when linked to Main panel, L1 it is limited to inverted power (one leg of generator wasted; may not be good for generator)
• Shore power 120v 15/20/30a L1 & L2 are jumpered. Inverter will block L2 but will provide inverted power on L2 to Main panel L1.
• Have to manually manage load usage to not overload inverter (likely the same with all options)
  

 

[zulu]

My biggest concern with the MPII is inability to use both legs of generator power. I don't expect to use the generator much with my solar installation but when I need it, I will need it.

Am I missing anything?

You CAN use both legs of a single phase RV generator – see posts #9 & #10.

 

[bpal]

That works for a smaller than 50A generator but would limit my 10k generator as shown in the following diagram.

 

[caymaanedge]

That works for a smaller than 50A generator but would limit my 10k generator as shown in the following diagram.

Well I will be in the same boat I think with an 800kw generator. How do I know if the output is in phase? Onan QD8000

 

[caymaanedge]

Well....thinking about this. I have the VE Direct Bluetooth Smart Dongle connected to the SmartShunt. I do not have an additional dongle on the Inverter. My MPPT has bluetooth and talks directly to the Smart Shunt so I am able to get battery, solar and consumption data via Victron Connect app.
So do I need a VE Bus Smart Dongle to connect to the inverter and get it in the loop? Thanks again.

 

[sneil]

Well....thinking about this. I have the VE Direct Bluetooth Smart Dongle connected to the SmartShunt. I do not have an additional dongle on the Inverter. My MPPT has bluetooth and talks directly to the Smart Shunt so I am able to get battery, solar and consumption data via Victron Connect app.
So do I need a VE Bus Smart Dongle to connect to the inverter and get it in the loop? Thanks again.

This is the dongle you need to connect to the MP II. That will give you access to the inverter via the Victron Connect app.

VE Bus smart dongle

 

[caymaanedge]

Thank You!

 

[sneil]

Thank You!

Glad to help.