Inverter/Charger Grid Backup design

[xthread]

Hi everyone,

I'm in the process of choosing all the components to make a grid backup system.
For now, I have a Honda EU2200i (1800w continuous, 2200w peak) generator 120v and the utility grid split phase 240v/120v.

The first phase of the plan would be to have an split phase inverter/charger take over when the grid goes down.
I would like around 1-2h of autonomy on the battery (Probably lithium) and would start the generator for the rest of the grid power outage.

I have for about 3kW peak, 1kW continuous of critical loads (Fridge, sump pump, water pump, sewer pump, lighting).
I would also need 120v and 240v hence the split phase inverter.
The system should also be scalable for solar panels, more batteries, more power as eventually, I would like to be off grid.

Up to now, the inverters that would make sense for my requirements seems to be those one.
Each of them offer pros and cons and this is where I need your expertise!

- Outback Radian GS4048A-01:
- Schneider Conext SW4048
- Schneider Conext XW+ 6848
- Schneider Conext XW+ 5548
- Magnum MS4448PAE

The Outback and Conext XW are dual ac inputs so I could wire my generator on one of the input without the need of transfer switch.
BUT they only accept 240v so I would need a tranformer to step up to 240v.

On the other hand, the Magnum and the Conext SW have only one AC input but accept 120v. So I would add a transfer switch to use my generator.
BUT when using 120v input, I read they charge half power and maybe let ac through also half power (not sure).
I'm also wondering if there is a way to have a quick setting change for charger current limitation and AC going through as I'll have full 240v power on grid but limited power on generator 120v.
Having to fiddle with charger setting each time there is a power outage would suck.

Not sure about this option as there will be losses but I could also maybe DC couple my generator using a battery charger and just charge my batteries.

So, what do you think about all that? Which way should I go?
Do you know of a better inverter for my application?

thanks

Dan

[Mike90250]

the Schneider Conext XW+4048 would be my choice. * It should handle all the listed loads fine (but not all at the same time)

I would also choose a Lead acid (flooded or sealed) over Li as a backup battery. The battery will be very under-utilized unless you have frequent outages - why pay for a li battery ?
for a 4kw inverter, I should pair it with a 400ah- 800ah battery. (who knows what your loads will be doing until you arrive to start the generator)

*
I have the XW-6048 and have used a high quality transformer to up-convert to 240V Generator support worked fine
you will need a SCP, or Combox or Gateway to program the settings (listed in order of expense)

my general settings:
Generator Support Enable Enabled
Generator Support amps 13.5 A (each breaker is only @ 120V so both will add, this setting = a limit internally derated to 2515w)
Generator Support PLUS Enabled

Honda EU2000i spec 13A 1600w cont, 2kw 30 min
AC2 Breaker Size 9.0
Generator Support amps 5.0
Battery Settings generic 48V but Float 54.4 Bulk/Abs 54.5

[xthread]

A little typo in my last post. Schneider Conext XW+ 5548 instead of 4048.

Thanks for the feedback Mike.
Good reasoning on the battery type.

My choice would be the same as yours but the price made me question myself.
I could get the XW+5548 for about 4700$CAD, XW+6848 for 5400$CAD and the SW4048 for 2700$CAD.
That's a 2k$ difference! On top of that, I won't sell to utility so one of the main feature of the XW would go to waste, hence my questioning.

Is there a reliability difference between the SW and XW?
What made you choose yours instead of the SW?

thanks

[Mike90250]

The SW used to be a stepped wavefrorm. not pure sine, but not nearly as bad as mod sine. And the XW has the 2 AC inputs (dual transfer switches)

The SW may work without the external autotransformer, but recent reports say with unbalanced loading, it's internal power consumption goes way up.

I know the XW+ actually works, reports have lots of issues with the SW not working as well. When off-grid, I don't want to mess around with stuff. And I have 2 actual backup generators, so AC1 & AC2 are not wasted.

[xthread]

Really good info like I was looking for, thanks.
XW+ falls into the same price range as the Outback.
Have you heard anything about those inverters? I know they are very liked by the community and have a good reputaton.
I'm wondering how they compare to the Conext.

Do you know of a good quality transformer I could use to step up my generator like you did?
Do I need an isolated transformer or an autotransformer will work? Do I need a neutral on the tranfo to connect to a Conext XW or just L1-L2 240v will work?

[Mike90250]

I found my transformer on ebay, took a gamble and it paid off.. You don't need isolated, but you do need a 240V CT winding you can use for
N - L1 for the generator and then you use L1 - L2 for the inverter connection, i don't think I wired in the CT to the inverter, but that was 6 years ago.

[neweclipse]

Keeping in mind your idea to expand in the future...
Outback and Victron both offer great autotransformers for this need...$500.00

Also, Starting with a Inverter/Charger wouldd eliminate need for added seperate charger...Outback for one...

[xthread]

Thanks neweclipse. I'll check them out.

To be honest, I'm still struggling between the SW and the XW+ considering the price difference.

reports have lots of issues with the SW not working as well.

I believe you but I'd like to have hard facts of internal difference between the two and/or those actual reports or any more info (features, etc) about why the XW would be better or more reliable than the SW.
If anyone have anything concrete.

recent reports say with unbalanced loading, it's internal power consumption goes way up.

I guess I could mitigate that with the transformer.

[Mike90250]

Thanks neweclipse. I'll check them out.
.......

I guess I could mitigate that with the transformer.

That would take 2 transformers, one to step up the 120V generator, and a 2nd to balance the output phases L1 & L2

What's the weight difference? The XW has a large (about 50lb) transformer, with total weight in the 80lb range if I recall correctly.

[Tecnodave]

I will only comment on part of this as I have little expereince with current Schneider gear. I use a MagnaSine MS4024AE Split phase inverter. When using 120 volt only input the pass through total power is reduced from 7200 watts to 3600 watts. The battery charging is reduced from 110 amps @ 30.0 volts to 55 amps @ 30.0 volts. The numbers are a bit different for the 48 volt version. I use two different ganerator, one 120 volts and the other 120/240 volts and it is a pain in the but to have to change settings when changing input voltage. Mine is older now and can't be set for amps but a percentage of full output. I use 100% on 120 volts and 50% on 240 volts. I have no grid and very rarely need backup power as my system is far larger than I need.

On autotransformers....the main transformer used in the MagnaSine units and the Schneider (C) SW units are autotransformers. This is why they can output 240 volts from 120 volt input.
You cannot use a 2 wire 240 volt input with no neutral leg.

I will politely disagree with Mike 90250 as to the need for two transformers, only one will be required, the Autotransformer as it will split the phase and do the voltage conversion. The power rating might have to be larger as incoming power will be on one phase only and that half of the Autotransformer is handling all the incoming power. I use an old Autotransformer with my ancient Dynamote Brutus 120 volt 3200 watt inverter to drive my 240 volt water pump. The Brutus has way more overload capability than the more powerful MagnaSine.........Brutus surge power, a whopping 11,900 watt from a 3200 watt inverter! vs only 5800 watts from the MagnaSine. Old tech lives on.....the Dynamote was the first high/low frequency inverter....high freq drivers feeding a low freq. transformer. I have two still working well but horrible standby useage! 96 watts idling....I only pump during max sun so issue with the idle power as I power it down when not pumping.

david

[xthread]

Thanks for your input David.

From what I can read, as I am already close to the max power output of the SW and Magnum, running them on 120v (no transfo) would not work for my application.
And having to change tthe inverter settings like you described is actually what I would want to avoid when switching between my 120v gen to the grid 240v.
So my inverter choice is becoming clearer...

I think that what Mike meant is to avoid unbalancing the SW (and his internal power going up) you need a transfo in input to get 240v and not use only half the inverter, as well as a transfo to the output to balance the legs as it is very difficult to match perfectly both 120v legs with loads
.
I take that with a grain of salt as it would still work with one or no transfo.
Anyway, it is really the kind of info I'm looking for as I can find the specs in the operating manuals.
But they won't tell you the weakness of the product nor his limitations in the manual.

[Tecnodave]

xthread,

if if your use is going to max out the magnum or CSW inverters then the XW+ or Radian is the far better choice. I have read many threads about the shortcomings of the CSW inverters. Schneider states they are the replacement for the TR line which was not true sine wave but were modified square wave. As an electronics tech I do not recommend anything less than true sine wave as other waveforms raise problems with certain electronics gear.

Unfortunately the XW+ and Radian do require 120/240 three wire input. I would not have bought the MS4024AE with what I know now but I bought it used with a minor problem which I could fix for a fraction of retail cost. It has served me very well but my loads are minimal.
If you have many power outages a 120/240 volt generator is the better choice rather than autotransformers.

Please note that I refer to the Schneider Conext SW units as the (C)SW unit as opposed to the Trace SW units which are not related to the Schneider (C)SW units and are true sine wave. Too bad they used the same exact model numbers as Trace used but Schneider did buy Xantrex which bought Trace.

smaller units can be stacked but that approach is fraught with problems with communication errors not found in larger single units. I have also read of problems with XW units stacked that fail to communicate after a system shutdown, sometimes damaging one of the units.

I do failure analysis of systems but mostly confines to battery issues, I do maintain one large XW dual inverter installation but have never had an issue with these older XW's. (not XW+) , very poorly done paralled battery banks, since correct with single string of large format 2 volt cells.

love my MidNite gear and am eagerly availing MidNite's new line of inverters. The B-17 line is groundbreaking. I want a MidNite Rosie the inverter 4 kW unit

disclaimer....I am a beta tester for MidNite for the Kid controller line and might be for the Rosie as well. With my training in electrical/electronics I much prefer well engineered units.....

david

edit: ...you would not be using only half of the inverter.....output power in inverter mode is not affected by input power, only the battery charging and pass through power is affected using 120 volt input...hope that helps your understanding of that issue...also using an Autotransformer on the input of the inverter will not help with load balancing on the output side of the inverter, I have heard of the load unbalance problem with the CSW units, I do not have that issue with my MagnaSine unit.

[xthread]

Interesting to know more about the origin of the CSW.
Despite coming from the square wave family, it seems it is now a pure sine wave.
At least according to their operating manual.

I bought a 120v, 50 pounds generator as I can easily transport it, does not consume a lot of fuel, really quiet and stackable by //ing them.
So in that optic, I'm ready to work with a transformer in the loop.

Let say I want to chose my autotransformer with the idea of having 2 Honda Eu2200i one day. Which size transfo should I buy?
2x2200W= 4400Watts. Ideally I wouldn't want one too big and not be able to run it with only one generator (inrush currents).

Would a 6kVA be ballpark?

[Tecnodave]

I would think so but I have little expereince with any inverter generators, they sip fuel and I will probably be buying a Honda as their are very reliable. All my generators are massive wound rotor types as their use is mostly for welding and have far more reserve power than smaller generators. I have two complete solar systems nearly identical that can be paralled for more capacity but I use them more for redundancy. To answer that question that will come up....the batteries are not a match , close but no cigar, one battery set is Interstate traction L-16 , the other set are Rolls-Surette S-530' L-16 , near same capacity but when paralled the Rolls batteries are overcharged...these are now 14 years old and still test at full capacity , salvaged from a failed solar system for $20.00/set with a voltage of 0.5 volts for complete set! My generators are repurposed motorhome generators, Onan Emerald 4 and Onan NE-3 6.6 kW 120/240..... not fuel efficient but have huge overload capability

[bcroe]

My generators are repurposed motorhome generators, Onan Emerald 4 and Onan
NE-3 6.6 kW 120/240..... not fuel efficient but have huge overload capability

I am curious if those Onans are diesel, or gasoline powered? They must be constant rpm, but
gasoline would vary the throttle with load. Experiments here on a 2001 small gas engine found
that the spark advance never varied for any reason. By varying the advance with manifold
vacuum and rpm, I was able to increase fuel economy, as well as performance. Bruce Roe