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Design of a split phase system 120/240V 60Hz with Victron Quattros

freemiguel

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Dec 17, 2022
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Hi to the community!

We want to build a split phase system 240/240V 60Hz (located in Panama) with Victron Quattros of at least 30kW.

My question is which Quattros I should choose and if an Autotransformer makes sense.

I have to explain what the system should be able to do:
We want to run a wooden dry chamber (theoretic maximum of 20kW) consists of different devices. Most of the time its should not exceed 13kW, but theoretical 20kW are possible for a short term. All devices are 240V/60Hz

Furthermore there will be a small carpenter workshop, with different machines. The machines (all of them are 240V) in the workshop won’t run at the same time. The maximum of one machine is 4kW on 240V.

For the 120V will be the light and maybe small tools like a drill machine, but again, not many machines at the same time. So I think, not more than 1200W.

Initially we wanted to take two of the 15kW Quattros split phase (30kW) but I noticed in the beginning that the 15kW model is only in 240V available. (Later on I noticed in the manual that it is possible to order a model 15kW with 120V, I have to find out if I can get this model).

So I have three options for the topology:

1. Suppose I get the 15kW model with 120V, I would have two of them as a split phase system. I don’t think that I run into a balancing troubles (between the 120V phases), because the heavy loads run on 240V.

2. If I don’t get the Quattro 15kW 120V model, I have to take 4 of the Quattro 8kW models. Two in parallel and split phase. So I would have 32kW power at the maximum. Of course more expensive and more work with AC cable wiring!



3. Suppose I take two of the 15kW 240V Quattros and I will use a Victron Autotransformer (100A) and still most of the most loads are 240V, will the Autotransformer be the right solution? I mean, the Autotransformer makes it possible to use the 240V Quattros and is balancing the two 120V phases (if I understand the function of an Autotransformer in the right way).

The rest of the system (beside the inverters) will be the following:

- 55 kWP module power with a few MPPT RS (I have to do the calculation with the Victron Excel, if I have the data sheet of the modules)

- 176kWh LiFePo4 batteries (15 pieces in parallel with 48V/230Ah connected with copper busbar)

- Lynx system, Cerbo, all connected via VE.Can
- ESS, the system should be capable to feedback electricity if the dry chamber/workshop is not used

- A generator (have to think about the size) if there is a power outage and the batteries will deplete



I am a technical engineer and I build up a three phase system in Austria (3x220/50Hz) with 3xMultis 5kW, 15kWP and a self built LiFePo4 battery (560Ah@48V). So I am new to split phase and electricity in general here in America.

I am happy about your recommendations or comments!

Michael
 
I would prefer two split phase units in parallel so that if one failed, you could still operate. From a reliability standpoint, reduce components and possibly run off one unit until you need the second.
 
While Victron is solid equipment, it doesn't necessarily make any sense to use an autotransformer when you could stack Schneider XW Pro models and get 240/120V split phase right out of the inverters. Two units will give you 14kW continuous, 17kW for 30 min and up to 24kW for 1 minute. If you need more then a 3rd unit could be added. The Schneider Power Distribution Panel (PDP) has all the AC & DC input and output breakers inside and can support up to 3 inverters. Last time I checked, Tom, the owner of TheSolarBiz.com lives in Panama his company has competitive pricing and he has forgotten more about solar then most people will ever know.
 
I would prefer two split phase units in parallel so that if one failed, you could still operate. From a reliability standpoint, reduce components and possibly run off one unit until you need the second.
Well, thats an argument for the 4x8kW solution. Thank you for your input.
 
While Victron is solid equipment, it doesn't necessarily make any sense to use an autotransformer when you could stack Schneider XW Pro models and get 240/120V split phase right out of the inverters. Two units will give you 14kW continuous, 17kW for 30 min and up to 24kW for 1 minute. If you need more then a 3rd unit could be added. The Schneider Power Distribution Panel (PDP) has all the AC & DC input and output breakers inside and can support up to 3 inverters. Last time I checked, Tom, the owner of TheSolarBiz.com lives in Panama his company has competitive pricing and he has forgotten more about solar then most people will ever know.
In my opinion Victron is one of the best in sense of reliability. And on the other hand I am familiar with it, and they have a great support.
An all-in-one solution is for some requirements o.k. But scalability is bad. Thank you for your advertisment, but the brand will be Victron, for sure.
 
Not sure what to make of your response, you asked for input. If you have already decided to exclude everything except Victron it kind of limits the relevant info that can be expected from the forum. For the record, I'm not affiliated with any companies or products so there was no advertisment content in my post.
Lastly, I have no idea how a Victron solution which requires both an inverter and an autotransform to increase output is somehow more scalable than an AIO inverter solution that can be added 1 at a time.
 
Well, thats an argument for the 4x8kW solution. Thank you for your input.
I was envisioning your first mentions of the Quattro 15 kw Split phase. Based on what I know now, would simplify to two units ideally or three if you need power above 200 amps at 240V.
 
I was envisioning your first mentions of the Quattro 15 kw Split phase. Based on what I know now, would simplify to two units ideally or three if you need power above 200 amps at 240V.
The thing is that the 15kW/120V model is normally not delivered. You have to do a separate order to Victron.

So that's the reason why we were thinking about the 15kW/240V model with an Autotransformator.
But it seems that we switch to a little bigger solution and will go for 4xQuattros 10kW, which is 40kW power. So two devices in split phase and two in parallel.
For each phase you can only have an even number; 3 devices are possible, but only for one phase.
But its true, the question I asked is very Victron specific. I put it also on the Victron community site.

But thank you for your suggestions.
 
The thing is that the 15kW/120V model is normally not delivered. You have to do a separate order to Victron.

So that's the reason why we were thinking about the 15kW/240V model with an Autotransformator.
But it seems that we switch to a little bigger solution and will go for 4xQuattros 10kW, which is 40kW power. So two devices in split phase and two in parallel.
For each phase you can only have an even number; 3 devices are possible, but only for one phase.
But its true, the question I asked is very Victron specific. I put it also on the Victron community site.

But thank you for your suggestions.
Okay, that makes sense. That should be fine.
 
I'm watching this thread with interest as I am going to be building a slightly smaller system for a new home build in Costa Rica. (My similar post)I have been debating the choice between 240v inverters with autotransformer or 120v inverters in split phase.

I think I'm leaning toward separate inverters doing the split phase partially for the reasons that JCS suggests in this thread and because its perhaps one less component and therefore one less thing that can fail.

I'm a Victron dealer (in USA) and I do not see that there is a such thing as a Quattro 15kw/120v that I can order including from The Netherlands. 10kw is largest so if you need 30kw you would get 3 of them but then you can't do split phase out of an odd number of units. You could do 4x10kw and have the option of having them produce the split phase you need without an autotransformer but that may be a waste and nearly double the money.

The 30kw requirement makes 2x15kw seem like the obvious choice but no 120v option so no native split phase and you are stuck using an autotransformer. Victron's larger autotransformer has a 100a (24kw) input breaker and a 100a max feed through current and 28a limit on Neutral. This isn't going to work to pass through 30kw.

In your scenario it is a bit different than a typical house where there are a bunch of 120v loads. If you haven't built this site yet and you have the flexibility to do it the way you want might it make sense to just do two separate panels. One 240v native panel fed by 2x 240v Quattros and natively giving 240v for your heavy loads. Then pull one branch circuit off this panel to feed the smaller Victron Autotransformer to feed a split phase panel but populate the panel with only 120v breakers.

Actually you really wouldn't even need split phase at that point. You need just one phase of 120v for the lights/receptacles so just a simple isolation transformer (Victron sell 2kva and 3.6kva) which creates one leg of 120v and feeds a small 120v panel for the lights and receptacles.

Victron does have Quattro 15kw/230v which of course can be reprogrammed to 240v/60hz. Two of these and a small isolation transformer would do it. If for some reason the transformer failed you would still have the main 240v systems working. And in this scenario the inverters would always be evenly loaded. But if one Quattro failed you would be dead in the water but this is the case anyway for the huge 240v loads you need.

There is also a Multiplus-II 15kw/230v which is just a bit less expensive than the Quattro but then you would need an external transfer switch for your generator if you have to use a generator. The Quattros probably make more sense if you have the genset input.


Just out of curiosity - what batteries are you using and are you getting them local in Panama or importing them yourself? What about PV panels? I'm starting to think about how I will source my gear in Costa Rica.
 
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