It's Working!!! Sol-Ark 15K, 33.52kW with 67 Panels AC+DC PV, 25kW SOK Batteries - Photo Diary

[zanydroid]

Afaik They couldn't: if the grid is up everything syncs to it so this should only be an issue in a grid down scenario

The scenario is, POCO needs to curtain and shifts to some reasonable amount past edge of the deadband.

Smart meter sees that you haven't cut back power like you were supposed to. It knows you were supposed to because it easily knows what the frequency is with some basic signal processing & resolution it operates at.

 

[1201]

The scenario is, POCO needs to curtain and shifts to some reasonable amount past edge of the deadband.

Smart meter sees that you haven't cut back power like you were supposed to. It knows you were supposed to because it easily knows what the frequency is with some basic signal processing & resolution it operates at.

I don't believe that can happen. If the grid is active the whole system follows the grid so no way the grid can send a signal to curtail and inverter still be active.

The inverter can only form the grid if the actual utility grid is down

 

[zanydroid]

I don't believe that can happen. If the grid is active the whole system follows the grid so no way the grid can send a signal to curtail and inverter still be active.

The inverter can only form the grid if the actual utility grid is down

The reason Frequency Watts was added to 1741SA was not so you could use it to AC couple.

It was so that the grid can change the frequency (or voltage, for the other functions) for the "whole grid" as a whole, and force every inverter on 1741SA to respond.

If you set the Growatt to a 0.2 Hz deadband and you're supposed to be on a 0.1 Hz deadband, presumably the growatt will always be at 0.2 Hz regardless of whether it's on or off grid (since it knows nothing about the on or off grid state). So when you're on-grid you have the wrong deadband value and will curtail less aggressively than your neighbors when the POCO decides to frequency shift the whole grid.

I guess what you could do is add some automation that adjusts the deadband.

 

[OffGridForGood]

Edit: Snow removal? The Photo Diary has a little video of 8-10" of snow sliding off the panels. Gravity seemed to take care of that.

if it is warm enough and the PV steep enough, snow should slide.

If it is cold, and the panel not very steep, could be less likely it will slide. My worst situation last year was freezing rain followed by cold night of snow sticking to the layer of ice on the panels. If it says cold, the ice layer will not let anything slide and the deep snow layer prevents the panel from warming up from solar (It seems snow blocks PV far more than ice does).

 

[1201]

The reason Frequency Watts was added to 1741SA was not so you could use it to AC couple.

It was so that the grid can change the frequency (or voltage, for the other functions) for the "whole grid" as a whole, and force every inverter on 1741SA to respond.

If you set the Growatt to a 0.2 Hz deadband and you're supposed to be on a 0.1 Hz deadband, presumably the growatt will always be at 0.2 Hz regardless of whether it's on or off grid (since it knows nothing about the on or off grid state). So when you're on-grid you have the wrong deadband value and will curtail less aggressively than your neighbors when the POCO decides to frequency shift the whole grid.

I guess what you could do is add some automation that adjusts the deadband.

Oh, I see what you mean now. So basically setting the wrong country code could cripple control from an active grid

 

[zanydroid]

Oh, I see what you mean now. So basically setting the wrong country code could cripple control from an active grid

Yeah, I don't know off hand what all is in the grid profile but it will most likely include the response parameters, which includes deadband size and how sharp the slope is. And probably things like the ride-through behavior.

 

[Ryushin]

BDM600, most recent version.

Note we're talking about the Grid tie Growatts here. Which I understand to be very different beasts from the off-grid Growatts. I keep them separate in my head.


Oh, do they do the flavor of UL1741 anti-islanding where they intentionally try to destabilize each other out of equilibrium until they lock out? I've sort of theory crafted that as a higher risk when AC coupling.

That is what it seemed to be in the beginning. James West from Growatt said that at 60.03 Hz the Growatt's start to curtail their output and that the Sol-Ark was not outputting 60.00 Hz. I've asked Sol-Ark to add another zero so we can see hundreds of a Hz. Either way, once James set the curtail to start at 60.2 Hz, the problem went away and both Growatts are running great.

 

[Ryushin]

Have you tried stress testing the SolArk with DC string off and turning loads on/off (to force the inverter to switch back and forth between invert and charge mode)? When I get more time I'll dig up a test plan I wanted some folks to do for science. I don't think SolArk recommends that you do that, I just want to understand a bit more about what kind of bad things happen when you abuse it like this.

I ran a day on just AC Coupled with no issue. From what I understand, Sol-Ark 15K has no problems running pure AC Coupled with no DC Input, as long as you have grid connected or a battery.

 

[Ryushin]

Just one for now but may add a smaller one later. What's the factory curtailment set at? Do you have yours set to ca rule 21?

Mine are set for the default grid input. James just made that one change. When off grid, I did see the Sol-Ark vary the frequency to curtail the output from the Growatts until the DC PV got to around 10kW, then the Sol-Ark just set the frequency to 62 Hz to shut down the Growatts all together.

 

[Ryushin]

if it is warm enough and the PV steep enough, snow should slide.

If it is cold, and the panel not very steep, could be less likely it will slide. My worst situation last year was freezing rain followed by cold night of snow sticking to the layer of ice on the panels. If it says cold, the ice layer will not let anything slide and the deep snow layer prevents the panel from warming up from solar (It seems snow blocks PV far more than ice does).

That could be a problem then. The video that shows the snow sliding off only as a 12:2 pitch. There is 38" of space on either side of that 16.8kW array. I could probably fairly safely get the nice 12' A-Frame ladder out that has a stand at the stop to move some of the snow off. If I was off grid I'd be more worried about it. If the grid goes down, and it's my only source of power, up on the roof I go. Not going to worry about the panels on the second story with a 12:6 pitch. When it warms up even a little they should slide off without a problem. Denver area snow usually does not stick around very long on roofs.

 

[zanydroid]

I ran a day on just AC Coupled with no issue. From what I understand, Sol-Ark 15K has no problems running pure AC Coupled with no DC Input, as long as you have grid connected or a battery.

Grid connected should be pretty stable with only questions about efficiency.

Was that one day with DC off and no grid? Full 24-48 hours that way, with battery cycling?

 

[Ryushin]

Grid connected should be pretty stable with only questions about efficiency.

Was that one day with DC off and no grid? Full 24-48 hours that way, with battery cycling?

20 hours DC off, no grid at the time. Sol-Ark charged the batteries up to my threshold for AC coupling, 95% at the time and shutdown the AC Coupling until the batteries got to 90% then kicked the Growatts back on to get it to 95% then off again. Ran on battery the whole night, in the morning it was down to 15% and the Sol-Ark had already dropped the frequency back to 60Hz when it dropped below 90%, so the Growatts started charging first thing in the morning.

 

[Ryushin]

Added more parts and source information to the first post. I think that will cover the equipment shown in the Line Diagram. Hopefully it will helps others as I spent a lot of time researching parts.

Saw a freak PV input of 26.1kW when the sun was shining directly on the panels and some puffy clouds were lit up as well. I seem to average about 17-19kW around noonish. Not too bad for November. Had a couple of cloudy days, one with some dusting of snow. Battery is usually topped off to 100% around 11:30. Seem to pull about 8-10kW from the grid during the morning before the sun comes up. Will need to add another three batteries to offset this so I can get through the night without using any grid. That will take us up to 40kWh.

November graph so far (got PTO on the 8th, but it was raining/snowing).

 

[zephyranthes]

I wondering if I should change the first post and add all the parts used and sources for those parts. I know it was a pain doing all the research needed for everything and sourcing it. Would this be beneficial for others?

I’m taking notes for my system. Thank you sir for this.

 

[Ryushin]

I was getting some questions in another thread about how much I spent and I kinda wanted to keep what I spent personal, but I guess that will be a big deciding factor for many. So I'll add to this thread what I posted.

I originally budgeted $38K. The system cost me about $55K. Went way over budget as you can see. Electrical components, wire, racking, were a lot more than I anticipated. I also added two more batteries to be able to supply power to the house during the night for us to go off grid for the estimated 7-10 days so I could finish the installing and wire up the grid portion of the install.

My total out of pockets costs, minus the 30% for the tax credit will be $39K. I expect my ROI will be about 8-9 years, including the batteries. But more importantly, we can be off grid if we need to. Though I still need to add a smallish 10kW NG generator with a EG4 Chargeverter to dump power into the batteries to be able to be fully off grid.

I built a large system to be more future proof. We want to add heat pumps for heating and cooling, along with heat pump for water heating. Also planning to add an EV in the future.

System has only had PTO for about 42 days at this point and we were off grid for about 25 days before that. The numbers:

October:
PV: 953 kWh
Load: 858 kWh
Export: 0 kWh
Import: 0 kWh
Discharge: 444 kWh
Charge: 476 kWh

November (PTO on the 9th)
PV: 2212 kWh
Load: 1545 kWh
Export: 888 kWh
Import: 373 kWh
Discharge: 681 kWh
Charge: 693.4 kWh

December (as of the 18th)
PV: 1140 kWh
Load: 1024 kWh
Export: 388 kWh
Import: 355.6 kWh
Discharge: 408 kWh
Charge: 409 kWh

In November, once we got PTO during sunny days we generated about 110 kWh on average. So far in December on sunny days we are generating about 92 kWh. December has been fairly hard so far as we've had some very cloudy days and snow covered panels a few times. Seeing about 17kW PV charge rate from 11am to 1pm in December. 25 kWh Batteries are usually topped off from 20% to 100% by 11:30am.

The Sol-Ark 15 is configured to not pull any power from the grid from 4pm-8pm as that is when my Time of Use rate starts and after 8PM I'll do grid shaving so that battery reaches about 20% by the morning. I'm still using about 8-11 kWh from the grid. We are planning on adding three more batteries that should take care of that so hopefully we won't use any grid at all if we have fairly sunny days.

Overall, I'm amazed at the system and geek out a bit watching it. Can't wait to see what we do closer to June 21.

 

[1201]

Hi. Quick question- the growatt manual says it has rs485 comms. Do you know where it is? Looking to do some solar assistant logging. Thanks

 

[Ryushin]

Hi. Quick question- the growatt manual says it has rs485 comms. Do you know where it is? Looking to do some solar assistant logging. Thanks

Yea, I found that information before in another of Growatts MIN 3000 manual:

Growatt MIN 3000TL-XH-US Installation And Operation Manual (Page 21 of 34) | ManualsLib

www.manualslib.com

James West from Growatt confirmed that information is correct.

 

[1201]

Yea, I found that information before in another of Growatts MIN 3000 manual:

Growatt MIN 3000TL-XH-US Installation And Operation Manual (Page 21 of 34) | ManualsLib

www.manualslib.com

James West from Growatt confirmed that information is correct.

wow this is excellent information, thanks!!
the inverter has THREE AGB ports and the 11.4 manual did not explain what they did or which one was which. so this helps a lot.

i hope it connects with solar assistant just fine.

gracias.

 

[1201]

Yea, I found that information before in another of Growatts MIN 3000 manual:

Growatt MIN 3000TL-XH-US Installation And Operation Manual (Page 21 of 34) | ManualsLib

www.manualslib.com

James West from Growatt confirmed that information is correct.

Got connected. I updated to latest version of solar assistant(the version I downloaded two days ago was not the latest ?)
.

For posterity, The port in the manual does not work with solar assistant. You have to use the rightmost port


growatt min tl-xh-us solar assistant

 

[Jbird905]

• Siemens 200 Amp 2-Pole 3-Wire General Duty Fused Outdoor AC Disconnect: https://www.homedepot.com/p/Siemens...-General-Duty-Fused-Outdoor-GF224NR/302352591

I have this exact disconnect and have an anecdotal story about it... Electrician was landing some circuits in the main panel (also the same exact panel as you). He was working live and with a slip of a ground wire, POW! It touched a bolt of the bus bar. After a bit of troubleshooting, we found it blew one of the 200A() fuses in the disconnect. One heck of a short circuit. Of course, this was Friday at 3:15pm, before a long holiday weekend. No area supply houses had that fuse in stock. Closest I could get was 150A, which at least got us running again. Note, we were able to run off-grid from the 15k, just couldn't use the grid, due to one leg gone.

^ Moral for me - Order one or two of those big fuses for backup. This stuff shouldn't happen, but when it does, it could be at the worst time.

Also Ryushin, I have been researching (and have posted a couple other places) for how to solve my needs. I have 22 more panels I'd like to AC couple to the 15k. Another inverter would be great for several reasons, including having a "backup" to the 15k. I couldn't find suitable inverters until I came across this thread. Thanks very much!

Here is what I am deciding between:

- Growatt MIN11400TL-XH-US: About $1000 after tax credit.

- Solis S6-EH1P11.4K-H-US-RSS: About $1400 after tax credit.

- Sol-Ark 15k: About $4150 after tax credit.

Main thing I don't like about the Growatt and Solis is that they are HV battery, with Growatt only theirs. Solis can do others. I have 48v Homegrid batteries now, so those two inverters could not charge my batteries. Of course, the 15k checks all boxes, but is $3k more.

As you did, I will run this by the home boss. Perhaps she'll just say "what the heck, just get the 15k."