Conext SW4024 - AC Support Performance

Hi everyone,
I've just set up a Conext SW4024 on a 24V battery bank and 1.6kW of panels. My house normally draws around 700W, and I'm finding that AC support is only covering about 300-400W of that. During full sunlight my panels are generating in excess of 1kW, so I find the inverter is very rarely able to hold the battery voltage at the AC support voltage.
Some reading has shown that I should have checked the fine print a bit better. The AC support for the SW only supplies the common current between L1 and L2, so if the currents are off balance at all then that will be made up by grid power.
I did a firmware update, hoping that new software might be better. No luck there. I was trolling through all of the settings on the combox and found an "Inverter Mode" option, and my inverter is current set to "Split Phase Master". There's an option for "Single Phase Master". I can't find any reference to this setting in my user manual. Does anyone know what this does? Will this change the output to be a single phase? Will this help the inverter with AC support since there is no longer L1 and L2?
Alternatively, does anyone know of any methods to improve the AC support for the inverter? I've already tried to balance L1 and L2 as best as possible by moving around some breakers, but I usually have a 2A or more difference between the phases, resulting in a lot of power being consumed from the grid needlessly. Even if it were possible to disable grid power when the battery voltage is above a certain level, that would be pretty neat, but I don't see any option for that.
Thanks for reading,
Giawa
6x Canadian Solar 260W Panels + 3x Jinko 260W Panels (2.34kW), Conext SW 4024 Inverter, Conext XW 60A 150 MPPT Charge Controller, 8x 220Ah 6V Flooded GC2 Batteries (4 per string, 2 strings in parallel for 24V 440Ah), MidNite Solar Combiner
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|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
http://forum.solar-electric.com/discussion/353094/balancing-the-loads-of-my-conext-sw-with-an-autotransformer
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Since I need 240v only periodically for a water pump, I set them up as master/slave 120v and run the pump through an autotransformer.
I don't know how a single phase master setup would work in a grid context though. Grid is normally split phase, so the inverter would only work on one half of the panel?
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Split phase is used predominantly in North America along with territories associated, Puerto Rico etcetera, but in fact most of the world uses single phase at a higher voltage, 220, 230,240V for domestic power. The designation for Schneider SW series inverter chargers are ended with NA or E, NA being split phase, E being single phase, internally my bet would be the only difference is the output transformer has a center tap grounded neutral to provide the split, 120/240V, which is why perhaps it has difficulty with AC support. Adding an auto transformer to re consolidate the split to re aquire single phase seems like a solution which adds further losses, if a single phase unit were used instead, with an auto transformer on the output to provide the split, it would probably be more efficient, but manufacturers probably design with common practice in mind, hense the North American designation, along with certificates, UL and CSA, which need to be met.
Random thoughts for what they're worth.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
It will take work by someone to make it work acceptably. It still seems like you are going to have to learn all of the ins and outs of advanced support.
As said by others split phase just makes it harder to make this very small inverter work well with unbalanced split phase loads. It is not too bad in non split applications with the grid but again, it really cries for the XW+ line of inverter/chargers when working with the grid.
Just compare the available power of a residence on the grid with the size of a CSW. Talk about imbalance!
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I own Outback and Schneider in my IRA and always want the stocks to go higher
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2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
It is not that hard to own privately held companies in your IRA BTW. If you have prefered shares that are often used as incentives to employees you can sell them and buy other stocks, bonds, ETFs or funds in an IRA and let it grow tax deferred. The same with cash payments of course.
"Private companies may also use stock options to pay vendors and consultants. ... options, giving the holder the right to purchase shares of the company's stock ..."
The problems in this thread with the grid charging on a CSW do not make sense to me. Either the unit is being programmed wrong, or it is defective. Schneider has used this since the XW+ came out in 2004. Does yours do this Horsefly?
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I also responded to you about how hard it is to do this with such a small inverter. As an inverter output "size" increases the balance problem decreases for most residential apps. This is why the XW was invented, not just to sell power but to be effectively sized.
In most of the world where split phase is not used, the CSW works better. What you could do is try and use 240V loads and minimize the issue
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BTW the smaller Radian has the same issues with balance in split phase power. It is about size afterall
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1. have cloudy days and get low
2. Need to charge when there is no sun
3. Need a full tank of super heated hot water if there has been no sun
So far it has worked out very well. It just would have been nice if the SW would have worked as advertised. Imagine, running all your off grid loads until the battery bank hi a certain threshold, the The sw would switch over to grid power, and if you wanted (you could have used charger time blocks) could have recharged the batteries.
As it stands right now, If I run ACS mode, my batteries never dis charge past 90% SOC before the sun comes up and floats them back up. It is more like "battery supports gird" rather than "grid supporting battery"
But an idea I had, maybe some sort of wifi smart box timer like this might work for AC grid in control. Not sure if it would work. I am sure that @Dave Angelini could tell us. But just a quick look at it would allow you to control the AC connection in to the SW with your smart phone and I think it has a timer option too. Looks pretty neat if it will handle the 240v 30amp AC in needs to the SW
I think the Autotransformer idea might be the best solution, but with a watt draw below 250-350 ... nothing ... no balancing or whatever is going to make the SW 4024 feed off the batteries. at low watts it will be supplied at or near 100% from the grid. And this is the main reason I did not get an autotransformer. Once I go to bed, my loads are so low, I would not draw from the batteries anyway. It is just easier to be off grid ... unless I need grid support.