Split phase/Single phase design questions

JefferyS

New Member
Joined
Aug 28, 2021
Messages
2
Hey all,

We are designing our off grid setup on our 5th wheel and have arrived at a puzzle we are struggling to solve. We have settled on a Victron Quattro 24/5000/120-100 120V for the center of the system. Our rig is a 50amp wiring setup, but we wanted the 24 volt and higher output of the Quattro as opposed to the Multiplus II which would accept the input of the split phase but is a 12 volt 3000 watt system. So now we are trying to solve the wiring of the 240 volt split phase into the Quattro. Ideally we would like to convert the split 240 into single phase 120 and feed it all into the Quattro and convert the rigs sub panel to single phase. This simplifies the wiring and load balancing concerns. We have been looking at Victron's Autotransformer but it is not clear if it does what we are considering. It looks more like it's designed to simply balance loads across the two lines, not combine/convert the input to single phase output.

We would like to avoid running one of the legs into the sub panel and the other leg to the inverter. Doing it that way requires some loads be unavailable when running on shore power and cuts the available current in half.

Running L2 into the AC/2 input of the Quattro is an option (maybe: the neutral is a puzzle here) but it is unclear if the Quattro will tap AC/2 when both are live. The wiring diagrams and literature lead me to believe it will switch between AC/1 and AC/2 but will not feed from both simultaneously. In fact I am unsure what happens if both are live. (On a side note: if a generator was wired into AC/2 in and both the generator and shore power where live, for example a 15amp mooch docking shore power feed supplemented by a generator, would it combine 1 and 2 for the hybrid feature or will it ONLY draw from the battery bank for the hybrid function?) If this is a misunderstanding that would make me very happy, but I doubt it, that would make the quattro essentially the same as the Multiplus II.

I have a very good understanding of DC current, and a reasonable grasp of AC current. When you start talking about the intricacies of split phase/single phase I begin to flounder. Any assistance and advise would be welcome.

Thank you in advance,
Jeffery and Carolyn
Arlington WA.

Edit: Updated the post with the more specific model of Quattro that we have.
 
Last edited:

FilterGuy

What, me worry?
Joined
Nov 26, 2019
Messages
4,493
Location
Los Gatos CA
I am not completely following what you want to do but I *think* the quatro will do what you want without re-wiring the breaker box.
First: Is the current 50A shore power feed feed a 240V split phase? (For this discussion I will assume it is)

I found this in the manual:
1630219198069.png
Accepts several input voltages (See fig 1)
Each AC input can be supplied from:

- A 120/240V split phase source. Phase angle between the two 120V legs: 180 degrees. Maximum input current: 60A per leg.
- A 120/208V two leg three phase source. Phase angle between the two 120V legs: 120 degrees. Maximum input current: 60A per leg.
- Two in-phase 120V legs with common neutral. In this case the phase angle between the two 120V legs is 0 degrees. Maximum input current: 60A total (otherwise the neutral input would be overloaded).
- A 120V single phase source. Maximum input current: 60A.
The AC inputs can be connected to a different type of supply: one input may for example be connected to a split phase source,
and the other to a single phase source.

When an AC source is available, the Quattro will feed through the AC to its output. The output will therefore be equal to the AC input.
When AC is available on both inputs, the Quattro will connect to AC-in-1.
The inverter/charger connects to the neutral and the preferred input leg (L1-1 of input 1 or L1-2 of input 2). Power needed to charge the batteries will therefore be drawn from L1-1 or L1-2.
The Quattro switches to inverter operation when no AC source is available. The inverter output is 120V single phase. In Invert mode, the Quattro connects both output legs (L1 and L2) together (with relay H) to provide 120 VAC to loads on either leg. In invert mode there is no voltage between L1 and L2. Any 240VAC or 208VAC loads will therefore be supplied only when the Quattro is supplied by a split phase 120/240V or 120/208V source. This prevents heavy loads such as water heaters or 240V air conditioners from discharging the battery.

This is a pretty interesting system. It will take single phase or split phase and pass it through to the output, but it only generates 120V single phase.

With this system, you would hook the Quatro AC-out to your existing split phase breaker panel using L1, L2, Neutral and Ground. Your breaker panel should *not* have a neutral-Ground bond.

Split Phase 240V Shore Power
AC1-in takes priority over AC2-In, so you would hook the split phase shore power to AC1 L1, L2, Neutral and Ground
* When 240 split phase shore power is present, the AC output will be split phase and drive all of the circuits in your breaker box. Note that if there are 240V loads on the breaker panel, they will be properly powered.
* When 240 split phase shore power is present, the inverter/charger circuit will charge the batteries from line 1 and neutral of the input. (L2 is not used)

Battery Power
* When no AC input is present and the inverter is driving the AC output, both legs of the AC output get tied together. Therefore both legs of the breaker box will be powered as a single phase 120V circuit. The interesting thing about this is that if you have any 240V loads (like an Air Conditioner), it will see zero volts when on the inverter and therefor not run.

120V single phase power. (This is where it gets 'interesting' )
* The easiest and safest way to connect the system into 120V single phase shore power would be to hook the inverter into line 1 and neutral of AC1. Unfortunately, the quatro just does a pass-through so only line one of the AC output will have power so half of your circuits will be dead.
* In order to drive both legs of your breaker panel, you would need an adapter pigtail with a 120V plug on one end and the 240V receptacle on the other. Internally, the hot wire of the 120 would connect to both L1 and L2 of the 240V receptacle (Ground and neutral would pass through to the respective pins on the 240V receptacle. The pigtail would plug into shore power and your 240V shore power cord would plug into the other side of the pigtail. This way both legs of the AC1 input on the quatro will have power and it will pass through to both legs of the AC output.

NOTE: When set up this way, you will need to be careful not to overload the shore power circuit.
NOTE: In this configuration, 240V loads on the breaker panel will see zero volts and therefor will not run. (The same as when in inverter mode)

240V split phase Generator Power.
If you have a 240V split phase generator, you would hook L1, L2, Neutral and Ground to the AC2 Input and it will act just like 240V split phase shore power (See above).

Note: The generator should have a Neutral-Ground Bond.

120V single phase generator.
If you have a 120V single phase generator, the Hot should be hooked to L1 and L2 of AC2 in and it will act like just like 120V single phase shore power (see above)

Note: The generator should have a Neutral-Ground Bond.
 
Last edited:

FilterGuy

What, me worry?
Joined
Nov 26, 2019
Messages
4,493
Location
Los Gatos CA
BTW: Here is a diagram of the pigtail I was talking about

1630255019005.png
You may need a few different versions in order to handle the various possible 120V receptacles that might be at camp sites.

* 120V 15A
* 120V 20A
* 120V Twist-lock 20A
* 120V Twist-lock 30A
 

JefferyS

New Member
Joined
Aug 28, 2021
Messages
2
Thank you for your response Filterguy, unfortunately you are looking at the European model of the Quattro. It is a 240V unit. Ours is the American version and a 120V model. Specifically it is the 24/5000/120-100 120V.

Our inputs are three wire, L1, N, G only. I will update the original post to make this clearer.

Jeffery & Carolyn
 

Tecnodave

Solar Addict
Joined
Mar 22, 2021
Messages
554
Hey all,

We are designing our off grid setup on our 5th wheel and have arrived at a puzzle we are struggling to solve. We have settled on a Victron Quattro 24/5000/120-100 120V for the center of the system. Our rig is a 50amp wiring setup, but we wanted the 24 volt and higher output of the Quattro as opposed to the Multiplus II which would accept the input of the split phase but is a 12 volt 3000 watt system. So now we are trying to solve the wiring of the 240 volt split phase into the Quattro. Ideally we would like to convert the split 240 into single phase 120 and feed it all into the Quattro and convert the rigs sub panel to single phase. This simplifies the wiring and load balancing concerns. We have been looking at Victron's Autotransformer but it is not clear if it does what we are considering. It looks more like it's designed to simply balance loads across the two lines, not combine/convert the input to single phase output.

We would like to avoid running one of the legs into the sub panel and the other leg to the inverter. Doing it that way requires some loads be unavailable when running on shore power and cuts the available current in half.

Running L2 into the AC/2 input of the Quattro is an option (maybe: the neutral is a puzzle here) but it is unclear if the Quattro will tap AC/2 when both are live. The wiring diagrams and literature lead me to believe it will switch between AC/1 and AC/2 but will not feed from both simultaneously. In fact I am unsure what happens if both are live. (On a side note: if a generator was wired into AC/2 in and both the generator and shore power where live, for example a 15amp mooch docking shore power feed supplemented by a generator, would it combine 1 and 2 for the hybrid feature or will it ONLY draw from the battery bank for the hybrid function?) If this is a misunderstanding that would make me very happy, but I doubt it, that would make the quattro essentially the same as the Multiplus II.

I have a very good understanding of DC current, and a reasonable grasp of AC current. When you start talking about the intricacies of split phase/single phase I begin to flounder. Any assistance and advise would be welcome.

Thank you in advance,
Jeffery and Carolyn
Arlington WA.

Edit: Updated the post with the more specific model of Quattro that we have.
An autotransformer will do what you are trying to accomplish. It will split the power used by the charger to both legs of the shore power feed. The charger/inverter and pass through will have a 120 volt input and output with 240 volts split phase as the power source.
 

FilterGuy

What, me worry?
Joined
Nov 26, 2019
Messages
4,493
Location
Los Gatos CA
Thank you for your response Filterguy, unfortunately you are looking at the European model of the Quattro. It is a 240V unit. Ours is the American version and a 120V model. Specifically it is the 24/5000/120-100 120V.

Our inputs are three wire, L1, N, G only. I will update the original post to make this clearer.

Jeffery & Carolyn
Could you provide a link to the manual? I would be surprised if the EU model dealt with split phase like the manual I looked at was talking about.
 

FilterGuy

What, me worry?
Joined
Nov 26, 2019
Messages
4,493
Location
Los Gatos CA
Interesting. Last night I found and downloaded the attached quatro manual and it is clearly targeted at the North America market. (I don't know where I found it). This morning I went to the Victron web site and found the manual, but can not find the product. :unsure:

It must be discontinued but that is a shame.... it is a nice solution for the NA market.
 

Attachments

  • Manual - Quattro 5k 120-240V - rev 02 - EN.pdf
    1.2 MB · Views: 7

cinergi

1.21 Jigawatts
Joined
Aug 9, 2020
Messages
1,162
If you're going to use a single inverter, an AT on the output side will give you two 120v legs and split-phase 240 AND it will balance the legs (up to 32 amps of imbalance IIRC). If your combined loads won't exceed 4kW and your imbalance < 32a (likely), I believe this is a viable solution.
When you plug into 50 amp 240 pedestal, you'll only be able to pull 50 amps from the pedestal (which is extremely unbalanced and not very nice to the system; I'd recommend setting the limit to 35 or less). I know the Quattro can pass through > 4kW ... I *think* it can use powerassist to go above that (e.g. you need more than 4kW while on shore power) by drawing the remainder from the battery but I'm not sure (would need to reread the manual).

My setup consists of two quattro 5k's and that gives me full flexibility for what I plug into at the pedestal (from 120v 15 amp to 240v 50 amp) and always retain 240v split phase inside (my mini-split requires 240). I've never come close to overloading one leg (each leg gets 4kW of sustained power), so this works well for me.
 
Top