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Victron Multiplus 12/3000/120-50 120V VE.Bus on 2 leg 50 amp shore power

I bought the Victron Multiplus 12/3000/120-50 120V VE.Bus to install in my RV. My current system:

1.3 Kw solar on roof

Midnite Classic 150 charge controller

4 225 Ah flooded batteries (plan to upgrade to Lithium soon)

12.5 kW diesel generator

(1) 50 amp shore power, plus )2) 30 amp shore power connections.

Generator and all shore power go to the AC panel through a selector switch, so i can select 30, 50 or gen power and the L1, L2. N and ground wire come into the panel from that switch.

To install the inverter, I am reading and understanding the only way with this unit is to run one line L1 tp the AC panel and the other L2 through the inverter and then back to the L2 side of the AC panel, which is already separated into the 2 legs.

I understand I must separate the neutrals between L1 and L2 -separate neutral bus bars for L1 and L2).

I only need inverter AC power for one side of the panel to run my fridge and a couple of other low power outlets. I would like the solar to provide all the DC required to run the inverter during the day (with excess going to battery charging.

I've been reading this board for hours and I can't decide if it's better to return the Multiplus and buy a quattro - is that a better choice (because it has two AC inputs) for my situation - or should I continue with the plan of separating L1 and L2?

If I separate L1 and L2 as described, when I use my generator to power all three air conditioners, the microwave and convection oven, with all of the required watts pass though the inverter? Or will the inverter limit how much can go through its leg?

Thanks,

Jim Phoenix



multiplus ve.bus
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gbntx avatar image gbntx commented ·

Does the 12.5kW generator output 120/240V split phase into the RV AC panel?


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jphoenix13 avatar image jphoenix13 gbntx commented ·

Yes, the gen legs, shore power legs all go through the selector switch to the AC panel. L1 powers one half, L2 the other half of the breakers.
What happens to the Generator when one leg goes through the inverter (along with that leg’s neutral) and the other leg goes direct to the panel?
my other concern is the inverter limiting one leg to 50 amps, what problems will that cause, if any?

Thanks,

Jim Phoenix

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gbntx avatar image gbntx jphoenix13 commented ·

Separating the RV panel Neutral Busbar in half and wiring in shore/generator 50A service is what goes over my head.

I don't have an onboard generator, but wanted to see how to do it if I ever get one. My diagram includes a generator plus an ATS and another ATS to monitor 50A service and route one leg through the Multiplus 12-3000-120-50 to feed the RV's panel.

Shore, Gen, ATS, Inverter-1.pdf

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shore-gen-ats-inverter-1.pdf (143.7 KiB)
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ben avatar image
ben answered ·
I understand I must separate the neutrals between L1 and L2 -separate neutral bus bars for L1 and L2).

You won't be able to do that, electrically at least. The neutral is shared and is electrically equivalent everywhere in your circuit.

Who told you that you had to physically separate them?

I only need inverter AC power for one side of the panel to run my fridge and a couple of other low power outlets.

Okay. You also need to make sure the other loads on that leg of the panel aren't enough to overload the inverter, or you have to accept that you may put it into overload and suffer shutdowns when you do.

Is that true? Most RVs have enough loads on either leg to overwhelm a small inverter. Think about whether you'll ever use those things at the same time.

I would like the solar to provide all the DC required to run the inverter during the day (with excess going to battery charging.

Sounds good, but irrelevant to the questions you've posed so far.

I've been reading this board for hours and I can't decide if it's better to return the Multiplus and buy a quattro - is that a better choice (because it has two AC inputs) for my situation - or should I continue with the plan of separating L1 and L2?

The Quattro would allow you to eliminate a transfer switch. Quattro can only switch two inputs, so a generator and a shore cord for example. If your switch has three selections, which I don't think is necessary for USA RVing by the way, you would still need a switch in front to be able to select from three choices of input.

If I separate L1 and L2 as described, when I use my generator to power all three air conditioners, the microwave and convection oven, with all of the required watts pass though the inverter? Or will the inverter limit how much can go through its leg?

The power for the leg you wire the inverter through (either L1 or L2) will go through the inverter in pass-through mode, or basically, directly. It will not limit it, as long as it is below the pass-through rating for the unit. See the datasheet for that number, but I believe it will be at least 50A, and so you'll be fine.

All of the above only holds if you have only 120V loads in your RV. Some RVs do have 240V loads. If yours is one of them, things are a little different.

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