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Grid Tie Inverter with battery options?
#1
Question 
I am investigaring inverter systems which will do:
1.      Grid tie
2.      Split phase 110/220vac NA power or have reasonably priced accessories to do so.
3.      ~5000VA continuous, with significant surge to start motors, including HVAC compressor, stackable and expandable.
4.      Efficiently route (excess) solar power to battery charging or from battery based upon demand for nighttime demand, peak shaving, back up power, etc.
5.      Meets US NEC code and has appropriate certifications for residential use.
6.      System can safely and legally create micro grid when the grid goes down to power home.
7.      Work with Bring Your Own Battery, lithium <60vdc
8.      Affordable for mortals and DIYable

Operate gridtie, MPPT solar, send excess power to batteries, at night use stored battery power until batteries run down to safe level, when back up power is needed then create microgrid to run select devices including one HVAC system.

I have come across the following systems, but none of them seem to meet all the criteria.
StoreEdge, Victron, Enphase, Conext, GTIL

StoreEdge. This is on the very short list.  It seems to do everything except that it requires an LG Chem ($8000) high voltage battery.  Defeating the idea of Second Life Storage.  But I did come across a bit of marketing guano on YouTube from Intersolar 2019 Munich.
https://www.youtube.com/watch?v=t60HZQKNi1o
He specifically mentions 48v 3-phase soon to come inverter with the ultimate goal to open the battery options beyond LG and BYD with no timeline, of course.  I do not know how much communication is required between the StoreEdge and the battery and what would be required to get it to work with a Battrium or other nice BMS.  I think the cost of the system, except for the $8000 battery, is the lowest by a nice margin, $2400 for a 7.6kva solar, 5kva battery, split phase 220v plus $400 for autotransformer, $325 for meter
The optimizer based system will also work the shading issues.

Victron.  Also on the short list, but seems to be missing the US certifications for the appropriate models.  Nearly all descriptions I find of these systems in NA and the stores which sell them involve an RV or boat and not a residential system.  The residential installs I found were all European. This would also require 2 inverters to get split phase, doubling the cost.  From what I can gather the Venus system is open sourced, which is awesome and it appears that it can be set up to be gridtied/microgrid/backup/store excess power.

Enphase.  Enphase has released a lot of marketing guano around the upcoming release of its Ensemble IQ8 based system.  This is probably at least a year out.  It can do some cool stuff like have the inverters self regulate output while in microgrid mode based upon demand.  The down side is that is uses the double inverter model.  You have inverters for the solar output and additional inverters for the batteries.  So in a fashion you have to purchase two inverters.  It is not quite that way because during solar production time, you will get full capacity, but during battery only, you will only have capacity based upon the battery inverters.

Conext.  This seems to be a common method to add battery backup to an existing gridtied system.  Essentially it is a complete off grid system which sits around and comes online when backup is needed and can AC couple with some gridtied inverters.  This was cool, but I need the next level and not have the additional system duplication costs.

Tesla powerwall.  Um Yes, but this is DIY Powerwall, they are the inspiration and I have a bunch of batteries and afaik Tesla still does not work when the grid/internet goes down.

GTIL.  Cheap! but fails many of the criteria, especially NEC code and UL certs. No storage option, no microgrid.

Does anyone have any corrections, comments or additions?
What have I missed?

I can’t move forward with my battery building until I know what the specs of the inverter and the rest of the system are.
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#2
Generally agree on the recap that you provided. I have been looking hard at the Victron scenario since I have found their MPPTs to be excellent. Challenge for me is ironing out what energy meter/meters that I need for split phase to properly limit power to just my household vs. pushing back to the street since I want to be able to offset my overall loads in addition to supporting a critical loads panel.

One correction on the GTIL scenario. They do support a battery bank and support one well. The 'cheap' version that I have allows for the cut-off and cut-in voltage to be set and has been working great the past year. Not a final solution but one that has allowed me to plan out my system. There are a couple threads here that highlight a few systems leveraging batteries. You just need to make sure you purchase one with the correct voltage range that is in-line with your battery bank, ex. I have the 22-65vdc range and my battery bank is 48v.

GTIL
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#3
U want a lot rearden... lol..I’m using 2 of the blue gtil2.. they can be powered by 60v battery bank. they are not UL listed for the USA, they work great. They feed single phase 240v to main panel. You do not need the extra neutral splitphase inverters supply. Good luck finding what u want...i do not think any of the grid tie inverters that are able to run off of batteries are UL listed atm
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#4
StoreEdge : 3-phase is completely different to split phase. You can't use a 3-phase unit for split phase (using 2 phases).

For reference, GTIL can be setup to work on a microgrid in conjunction with a 'suitable' off-grid inverter. Totally unconventional and not for a first time DIY option.....
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#5
I do want a lot, and a Pony!
You are correct that 3-phase is different that split phase.  What I was most interested in was the admission that they needed to open things up to support 48v batteries from the general market.  I think StorEdge does exactly what I want to do, except for the requirement of using the expensive LG Chem high voltage battery.  It seems the battery voltage matches the string voltage and probably significantly reduces the current carrying needs in the system.  High voltage DC scares me. If the system would work with any battery, I would probably build a high voltage version. 128s8p, in groups of 16s.

Thank you for your replies!  It seem like a lot of people are using GTIL.  Anyone heard of any plans for them getting US certifications?
I did not know that they could also handle power flows from and to batteries, solar and grid while also preventing export.

Does the Victron ESS wiki address the split phase metering, inverter stacking?
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#6
Schneider Conext XW+ and Outback GS. They both are grid-tie capable and are 48V. Both are I believed to be certified in the US.

On a side note the original GS was designed by the same engineer as the XW, back when it was Trace Engineering and he moved to Outback then I believe to Midnite.
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#7
GTIL are discharge only, they are HF internally and do not allow power to flow in reverse (charge the pack).
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#8
throwing a piece of wood in the hen house:
Why not 6 phase, i am serious btw and NOT joking.
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#9
Why 6 phase ??? What would be the point?
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#10
I think, that 6 phase is more energy efficient, for electric motors?
And get more power/torque?
But i think i could be wrong on this one.
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