Growatt 12000T AC coupling setup wiring help please!

[bhoth]

I just purchased the 12000t and I am confused about the AC input and output. It seems to me if I connect them both to the same panel I would just have an inefficient loop.

My setup so far is 26 REC 360 watt panels connected to Enphase lq7+ micro inverters on a grid tied system. That system feeds into my main panel on the outside of my house, which is 200 amps. Inside that 200 amp panel are (2) 100 amp breakers that feed 2 panels down in the basement. I will be making 1 of the 100 amp panels my critical needs panel. I have mounted the 12000t next to the critical needs 100 amp panel in the basement. I have ordered from Michael here on this forum, 32 cells to make 2 sets of 16s batteries (48volts).

My thinking is when the grid is down, manually kick the 200 amp breaker from the grid to the off position(Yes I know I need to get some kind of interlock setup so no one can turn the grid switch back on with out first turning off the 12000T), then turn on the 12000t which would power the 100 amp critical needs panel, and power would go back up to the 200 amp panel. The Enphase setup would see power (thinking the grid is back up) and turn on the solar panels. The solar setup would then be providing power to the 200 amp panel then would then come back down to both 100 amp panels. (I could could kick off the non critical needs panel circuit breaker in the 200 amp panel to conserve power when needed)

So far I am thinking I can only use either the AC input or the AC output at any one time but not both. The AC input of the 12000t would be connected to an 80amp breaker in the 100 amp critical needs panel to keep the batteries topped off while the grid is up and solar power is being received from the solar panels.

When grid power is down, I would kick off the main grid 200 amp breaker, then walk downstairs and switch the wires from the AC input on the 12000t to the AC output on the 12000t then turn the inverter on.

Is my thinking correct? If I have both the AC Input and the AC output connected to the same 100 amp critical needs panel when the grid is up, I would have an AC loop right?

Please help!

 

[schmism]

I don't think it works.

1) I would think you would want to charge the batteries on the growatt via the "grid" enphase solar. The only way to do that is to keep the AC input connected.
2) As I understand the grid tie micro inverter systems, they reley on the grid being able to take as much power as they will produce at any sec. They effectively have an off and full throttle, there is nothing in between.

How does the system throttle the enphase when the house load + battery charging load is below the current output of the solar?
House load is say 100amps How does the Growatt know that that the solar is providing 50 amps so it should only provide 50 additional amps?
House load is 100 amps that is made of up 30amps on the 220 panel and 70 amps on the critical loads. Enphase puts out 100 amps, how do you get the other 70 amps directed to the critical loads? (i dont think you do, unless you put the growatt into grid bypass)

3) I thought the enphase was single phase 240v and it "floats" This works for the grid because it pulls the one "side" down. The enphase does not produce 120v single phase. (if that understanding is correct... im not sure it is...) then your 110v loads in your 220a panel will not be powered.

As I understand, the best way to get something that works when the grid is down is to add batteries to your enphase system. There is a fairly extensive thread on the forums about this. https://diysolarforum.com/threads/adding-storage-to-my-enphase-system.10797/

 

[BenQ]

Yes if your Growatt inverter is set to utility mode and your batteries need to be charged then you would be creating an AC loop. Under usual cases this is not a good thing and your batteries will self consume at a ridiculous rate. If your enphase system is producing enough energy then it won’t matter because the load on your GW inverter will be minimal and the batteries will hit full charge quickly and the loop will end (a/c charger only kicks on and off at defined limits).

This brings up the fact that this GW inverter is not supposed to be used in this way. It is NOT a hybrid inverter. Grid tied inverters push voltage, watts and amps at a slightly higher frequency to reverse the flow of electricity back to the grid (back feed) if your enphase system thinks your GW is the grid it could really fuck it up. I’m not sure if the AC loop mentioned above will help with this, but I doubt it. In my research and limited experience the only thing that keeps this from going bad is having a dump load so that all solar energy produced is consumed and nothing is pushed back to the grid, or in this case your GW.

Hope this helps and I hope you work it out!

 

[BenQ]

For more about true hybrid frequency shifting check this Post in thread 'Solar Edge grid tie to ac couple'
https://diysolarforum.com/threads/solar-edge-grid-tie-to-ac-couple.17588/post-203115

 

[Ironman]

Looked it up in the manual on page 8, it tells you that output is powered by the grid when the LED is green, green flashing is battery powered output.
The Introduction says that input from a generator or powerline can flow through to the output. It can also have battery charging from these sources and battery assisted output, which I assume means that if your genny is too small for the load then the batteries will help boost the watts.
It is described as an off grid inverter in the manual, however it seems to have every feature except shutting down when grid power is down