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Woody asked

Setting up Parallel Multiplus for a 50Amp RV all documents are very imprecise...

So a 50amp RV shore outlet is actually two 50amp connections for a total of 100amps right? So when I program my multiplus inverters, is my input current limit 100amps meaning I program 50amp or is it 50amp and I program 25amp? Or am I totally misthinking this because it mentions "per phase" and a parallel system is single phase so I should just set it to 100amp... or is that 50amp...


I'm following the following information from the Parallel and three phase VE.Bus systems document

The following settings need to be made in the master of each phase:

  • Inverter output voltage

  • Input current limits
    (the effective input current limit is the setted limit multiplied by the number of units per phase. For example, setting a 10A limit with VEConfigure in a system with two units per phase results on a 20A limit for that phase. Being able to set a different limit per phase allows for maximum configurability.


Also when I'm looking at the maximum charge current, if my total charge limit is 70amp I would set it to 35amp?


multiplus in parallelshorepowerinput current
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solardude answered ·

A diagram of how you are setting up the system would be helpful. Are you only inverting one leg of your 125/250 system? Or are you trying to invert both legs (split phase system)? If you are stacking 2 inverters (parallel) then you can only connect it to one leg and get 120V.

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Woody avatar image Woody commented ·

One thing maybe I did not make clear, is that I only want 120v. I don't need 240v. I really just want to be able to produce the most amps possible while on batteries. Is this going to happen with a split phase or a parallel system or something different entirely?

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solardude avatar image solardude Woody commented ·

Split phase will give you the most available power. You don’t have to use 240V just because it is configured as split phase. Using either leg of 120V plus neutral will give you 50A AC per leg @120V.

I guess it also depends on how many watts your inverter is. What models are they?

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Woody avatar image Woody solardude commented ·

But wouldn’t just leaving the two multiplus 24v 3000/70 in stand alone mode running half of the electrical panel produce the same result? They would each get 50A from one of the two split phase legs and pass that as split phase to the panel (this is how I currently have it set up) but when you switched to battery they would just provide power to whatever is drawing?

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Woody avatar image
Woody answered ·

I'm setting the system up in parallel. I have no need of 240v split phase as I have no 240v appliances. I'm trying to get the most AC bang for my buck specifically when on batteries, if there is a better way to do it I'm open to redoing the system. I've attached my schematic below.


solar-battery-system.jpg (592.8 KiB)
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solardude avatar image solardude commented ·

I don’t think it will work as drawn. You Basically have a split phase schematic. The shore neutral can’t be used for 2 different inverters unless you wire it in split phase, or they are truly paralleled and use only 1 hot and the neutral.

I would set up in split phase. This way the neutral only carries what imbalance exists between L1 and L2.

Stacked (or parallel) system can only utilize one hot and a neutral and won’t allow full use of the shore input.

An even better solution would be to get one larger 230V inverter and an autotransformer. It will utilize full shore power and will balance the loads between L1 and L2.

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Woody avatar image Woody solardude commented ·

Well it's too late for a new inverter, so this is what I have to work with. I've been getting a lot of contradictory information on parallel vs split phase. I can't find and nobody can tell me which one is better for my situation or even make arguments for one over another. Right now it's wired as two stand alone systems each powering one half of the breaker box. While on shore power this works without issue. When I switch to run on batteries I get overloads when I run A/C with another high draw device like toaster, hair dryer etc. on the same side of the breaker. I was told that parallel would allow the two inverters to work together to overcome those sorts of issues. I don't see how split phase can as it seems the two inverters are still basically just stand alone devices unless you have a 240v appliance. Am I right in this?

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