System planning for an AC coupled Grid tied system

[magic8192]

I currently have a grid tied PV system with 12 AP Systems QS1 1200 watt micro inverters with 48 320 watt 72 cell panels. My big snag right now is finding the right inverter and the right monitoring. Any feedback is appreciated.

My priorities:
Charging from PV only
Minimize grid usage, but it is OK to use.
-I get paid wholesale for power (almost nothing)
-Use the grid for a dump when extra PV is available I don't have frequency controlled inverters (older)
Use the battery at night to lower power usage.
Grid goes away and nobody notices.


I currently have an older lithium Ion 48V battery with about 20KWH of energy storage
I have 16 Lishen 270ah battery cells on the way for about 13KWH of energy storage.
The plan is to transition over to all LifePO4 cells moving forward about 4 of the Lishen 16 cell batteries.
The wife hates Li Ion. She has seen too many videos of burning Lithium Ion batteries.



Here is a simple block diagram of what I would like to do.

 

[svetz]

48 panels x 320 watts = 15.4 kW array.
You have Microinverters, so already have AC off the roof.

The big thing your diagram is missing is some sort of ATS to prevent back-feeding the grid (there are "smart" ones too, for example Enphase has the Encharge for their solution and Tesla has something similar).

You should probably check to see if the Tesla powerwall is compatible with the AP Systems microinverters (e.g., Tesla and Enphase have AC batteries that work with Enphase's IQ7 microinverters).

If not, you'll need an AC coupling solution as you've mapped out. There are a few of those, Schneider, Magnum, Outback, SMA. Not sure if the new Sol-Arc plays in that sandbox or not.

 

[magic8192]

48 panels x 320 watts = 15.4 kW array.
You have Microinverters, so already have AC off the roof.

The big thing your diagram is missing is some sort of ATS to prevent back-feeding the grid (there are "smart" ones too, for example Enphase has the Encharge for their solution and Tesla has something similar).

You should probably check to see if the Tesla powerwall is compatible with the AP Systems microinverters (e.g., Tesla and Enphase have AC batteries that work with Enphase's IQ7 microinverters).

If not, you'll need an AC coupling solution as you've mapped out. There are a few of those, Schneider, Magnum, Outback, SMA. Not sure if the new Sol-Arc plays in that sandbox or not.

The Encharge and Tesla power wall are probably not a good fit for me. I think you have to have enphase inverters for the Encharge? and I already have a good bit of battery storage. I am trying to move away from Lithium Ion anyway.

 

[magic8192]

I was looking at the sol-ark 12k, but I would need 2 of them and 14,000 is a little much for me.
I have a quote for 2 SUN-8K-SG01LP1-US/EU for around $4000 delivered I think service and warranty will be a hassell if needed
I have a quote for 2 Sunny Island 6048-US-10 inverters for around $4000 delivered. 7 years of warranty left is nice.

The Sunny Island inverters seem like beasts, but off-grid is not my first choice. sigh

 

[magic8192]

Decided to go with the 2 Sunny Island 6048-US-10 inverters.

 

[magic8192]

This has been moving really slow. Mainly because I couldn't get batteries. I now have 48 280 ah LiFePo4 batteries that I have been top balancing. The REC Q Series BMS 16S is on the way and all the wiring on the outside of the house with the exception of connecting the wires from the SI inverters to the disconnect.

I haven't determined if I am going to hook my generator to the generator connection on the Sunny Islands or hook up the electric grid to the generator connection?

 

[magic8192]

The batteries are all top balanced. Now just have them all hooked together waiting for me to have the time to build the battery.

 

[magic8192]

I am almost done. Looks messy because it is

 

[Cessmation]

Thanks for posting these. I have a much smaller solar panel system with micro inverters and I expect this will help.
4 AP Systems QS1 1200 watt micro inverters with 24 count 310w panels or so.
So I need an AC coupled inverter for my grid tied system and a 48v battery bank.
Pretty much the same as yours correct?
How do you like Sunny inverters?
Can I ask you for the link to your batteries you purchased along with possibly a better/updated blueprint of your system?
I'm finding it very difficult to get a good blueprint of what I'll need/want.
Thanks again for your posting Magic!

 

[magic8192]

I have a manual 200 amp transfer switch. When the transfer switch is up, it feeds power from the grid to the backup power on the Sunny Island inverters. When the transfer switch is down, it feeds power to the secondary loads panel. I have a manual lockout switch between the Sunny Island breaker and the mains breaker in the load panel. Only thing not shown is the BMS wiring.