12KW Growatt increasing size of my PV array and need advice please.

[hotrod]

According to Growatt USA and Signature Solar I only have my 12 kw Growatt inverter running at about half capacity with my currant solar array. I have 24 - 260 watt panels running to my growatt inverter now 12 panels 3s4p on each pv string. I currently have it set up as 12 panels 3s4p on each pv string going into the inverter. which gives me 113.7 voc , 35.6 Isc and 3120 watts on each string. According to Growatt and Signature Solar I can go as high as 250 vdc 7000 watts on each string of this inverter. Not to exceed 120 charge amps combined on both strings. So now I want to put all 24 -260 panels on 1 pv string and I have purchased 30 used Q-cell 265 watt panels that I want to install on the other pv string on my inverter. 15 panels facing east and 15 panels facing west can you suggest what will be the best way to configure these panels for each string. I am currently running everything thru 2 Midnight solar 6 string combiner box's with 20 amp breakers on each string only using 4 strings in each box at this current setup.

Would this combination work ok
1st string Hyundai 260 watt panels.
24 panels 4s6p 6240 watts voc = 151.6 and Isc 53.4

2nd string Q-cell 265 watt panels.
30 panels 5s6p 7950 watts voc = 191.75 and Isc 55.08
1 string going into 1 midnight solar 6 string combiner box and 2nd string going thru the other 6 string Midnight solar combiner box.
I know the 7950 watts will be more than the 7000 watts max on each pv string input to the inverter but I'm thinking with 15 panels facing east on my shop 4x12 pitch roof and the other 15 facing west shouldn't ever produce the full 7950 watts its rated at.
What you guys and gals think, would this be the best way to configure these panels for my inverter. or is there a better setup for them.
By the way I just purchased these 31- 4 year old used 265 watt Q-Cell panels for 1000.00 cash local pickup couldn't pass that deal up for sure.

 

[Vigo]

What purpose are the combiner boxes serving in this case?

I agree that you likely dont need to worry about exceeding the solar input limit. You probably aren’t ever hitting the existing 3120w number either.

I’ve made absolutely no attempt to improve my panel orientation or wiring yet (although i plan to eventually) and have never seen more than 7xxx watts from my 10000w of panels. The only time ive even seen the 7kw was when i had all my normal loads covered at 5-6kw and was turning on ‘spurious’ loads to see what was left in the solar. ?

But that’s why i bought 10,000w of panels. So i could choose to be lazy! Considering you are doubling your PV for $1k you can probably choose to be happy with whatever you get here too. I dont think the mppts are in any danger.

 

[hotrod]

What purpose are the combiner boxes serving in this case?

I agree that you likely dont need to worry about exceeding the solar input limit. You probably aren’t ever hitting the existing 3120w number either.

I’ve made absolutely no attempt to improve my panel orientation or wiring yet (although i plan to eventually) and have never seen more than 7xxx watts from my 10000w of panels. The only time ive even seen the 7kw was when i had all my normal loads covered at 5-6kw and was turning on ‘spurious’ loads to see what was left in the solar. ?

But that’s why i bought 10,000w of panels. So i could choose to be lazy! Considering you are doubling your PV for $1k you can probably choose to be happy with whatever you get here too. I dont think the mppts are in any danger.

The combiner box gives a good place to tie all of the strings into one place with a breaker on each string and then leave with only 1 run from the combiner box at the pv array to the inside pv breaker before going into the inverter pv input.

 

[hotrod]

What purpose are the combiner boxes serving in this case?

I agree that you likely dont need to worry about exceeding the solar input limit. You probably aren’t ever hitting the existing 3120w number either.

I’ve made absolutely no attempt to improve my panel orientation or wiring yet (although i plan to eventually) and have never seen more than 7xxx watts from my 10000w of panels. The only time ive even seen the 7kw was when i had all my normal loads covered at 5-6kw and was turning on ‘spurious’ loads to see what was left in the solar. ?

But that’s why i bought 10,000w of panels. So i could choose to be lazy! Considering you are doubling your PV for $1k you can probably choose to be happy with whatever you get here too. I dont think the mppts are in any danger.

 

[Vigo]

I cant see the column titles but im guessing the 3000 number is watts, in which case you’re getting dang close. My strings are 11s2p, and as i understand it the longer your series strings the greater the chance for the conditions of any one panel or connections between any two panels or just the total length of wiring in the string etc to degrade the putput of the whole string. Even bypass diodes aren’t ‘free’. I didn’t even take any particular care for the cleanliness of the mc4s on my used panels. I think i blew in them like an old nintendo cartridge and slammed em home. I anticipate i could probably get ~1000-1500w more watts out of what i have by orienting better, cleaning connections, etc.

But hopefully one thing you WILL have in common with my lackadaisical install, is that if you were getting by before and then double your pv, you get to the point where ‘getting the last nth out of it no longer matters’.

 

[hotrod]

I cant see the column titles but im guessing the 3000 number is watts, in which case you’re getting dang close. My strings are 11s2p, and as i understand it the longer your series strings the greater the chance for the conditions of any one panel or connections between any two panels or just the total length of wiring in the string etc to degrade the putput of the whole string. Even bypass diodes aren’t ‘free’. I didn’t even take any particular care for the cleanliness of the mc4s on my used panels. I think i blew in them like an old nintendo cartridge and slammed em home. I anticipate i could probably get ~1000-1500w more watts out of what i have by orienting better, cleaning connections, etc.

But hopefully one thing you WILL have in common with my lackadaisical install, is that if you were getting by before and then double your pv, you get to the point where ‘getting the last nth out of it no longer matters’.

Yea I don't see the 6000 watts very often it normally peaks at 5000 to 5500 watts for a brief time during the day if I have no clouds and my 600 ah battery needs a good bit of charging and I have a decent load on the inverter. Adding this new array should give me a possibility of up to 14,000 watts with perfect conditions which I don't think I will ever see. As long as the voltage don't go over the 250v per string I think the wattage will throttle itself back if 1 string gets above the 7000 watts. And yes I really don't think I will have to try to pinch every little watt I can get out of this system once I get the second array installed and up and running.

 

[hotrod]

I'm getting 25 to 30 KW of solar a day pretty regularly now with my 6.2 kw's of solar panels. So hopefully I will see 50 kw and above pretty regular after I get the other 8 kw of panels installed.

 

[godsglory22]

According to Growatt USA and Signature Solar I only have my 12 kw Growatt inverter running at about half capacity with my currant solar array. I have 24 - 260 watt panels running to my growatt inverter now 12 panels 3s4p on each pv string. I currently have it set up as 12 panels 3s4p on each pv string going into the inverter.t

Ok you guys are right where I'm very confused about.
And thank u in advance as im a mom of 6 doing this all on my own due to finances and only have YouTube education on solar
??
I have the same growatt inverter 12kw off grid. I'm doing this all myself with only internet education lol. I just do t understand if each array can be up to 150vdc, or is that the total maximum all arrays should equal?
What I currently wired I'm now reading it's wrong, I've yet to flip the switch thank God.
Here's what I did:
1 (6) combiner box
18 Canadian (395w) 46.7v & 10amp
bifacial panels
Wired 3 in series, 6 a5rd rrays
Gave me 144voc

According to Growatt USA and Signature Solar I only have my 12 kw Growatt inverter running at about half capacity with my currant solar array. I have 24 - 260 watt panels running to my growatt inverter now 12 panels 3s4p on each pv string. I currently have it set up as 12 panels 3s4p on each pv string going into the inverter. which gives me 113.7 voc , 35.6 Isc and 3120 watts on each string. According to Growatt and Signature Solar I can go as high as 250 vdc 7000 watts on each string of this inverter. Not to exceed 120 charge amps combined on both strings. So now I want to put all 24 -260 panels on 1 pv string and I have purchased 30 used Q-cell 265 watt panels that I want to install on the other pv string on my inverter. 15 panels facing east and 15 panels facing west can you suggest what will be the best way to configure these panels for each string. I am currently running everything thru 2 Midnight solar 6 string combiner box's with 20 amp breakers on each string only using 4 strings in each box at this current setup.

Would this combination work ok
1st string Hyundai 260 watt panels.
24 panels 4s6p 6240 watts voc = 151.6 and Isc 53.4

2nd string Q-cell 265 watt panels.
30 panels 5s6p 7950 watts voc = 191.75 and Isc 55.08
1 string going into 1 midnight solar 6 string combiner box and 2nd string going thru the other 6 string Midnight solar combiner box.
I know the 7950 watts will be more than the 7000 watts max on each pv string input to the inverter but I'm thinking with 15 panels facing east on my shop 4x12 pitch roof and the other 15 facing west shouldn't ever produce the full 7950 watts its rated at.
What you guys and gals think, would this be the best way to configure these panels for my inverter. or is there a better setup for them.
By the way I just purchased these 31- 4 year old used 265 watt Q-Cell panels for 1000.00 cash local pickup couldn't pass that deal up for sure.

What your doing is exactly what I'm confused about .
I too have have the off grid 12kw growatt inverter.
I'm confused at the basic understanding of how much amps or volts I can have in each array and total.
Here's what I have and how I configured it.
What I have:
1 (6) combiner box
18 Canadian bifacial panels
395w 46.7v 10amps

How I Wired it:
6 arrays
3 panels each connected in series

Is this ok???
Or:
3 arrays with 3 panels in series
and
3 arrays with 3 panels each in parallel?

Or?

 

[kromc5]

I went through something similar with my two 12kw growatts. Many say its ok to over panel but speaking directly to growatt they are emphatically against it. It's 7000w input but that is split among the two chargers.

 

[kromc5]

Ok you guys are right where I'm very confused about.
And thank u in advance as im a mom of 6 doing this all on my own due to finances and only have YouTube education on solar
??
I have the same growatt inverter 12kw off grid. I'm doing this all myself with only internet education lol. I just do t understand if each array can be up to 150vdc, or is that the total maximum all arrays should equal?
What I currently wired I'm now reading it's wrong, I've yet to flip the switch thank God.
Here's what I did:
1 (6) combiner box
18 Canadian (395w) 46.7v & 10amp
bifacial panels
Wired 3 in series, 6 a5rd rrays
Gave me 144voc

What your doing is exactly what I'm confused about .
I too have have the off grid 12kw growatt inverter.
I'm confused at the basic understanding of how much amps or volts I can have in each array and total.
Here's what I have and how I configured it.
What I have:
1 (6) combiner box
18 Canadian bifacial panels
395w 46.7v 10amps

How I Wired it:
6 arrays
3 panels each connected in series

Is this ok???
Or:
3 arrays with 3 panels in series
and
3 arrays with 3 panels each in parallel?

Or?

Your in problematic area with your panels as they are very similar to mine. You cannot run a 3s if it gets cold where you live. The problem I had was the inverters would not run on 92v. Soon as the loads came on the panels would sag and the inverters would turn off pv all together. In the end I had to buy 250v charge controllers and stop using the growatts all together. There have been firmware updates so I not sure if you will run into this issue.

 

[hotrod]

Ok you guys are right where I'm very confused about.
And thank u in advance as im a mom of 6 doing this all on my own due to finances and only have YouTube education on solar
??
I have the same growatt inverter 12kw off grid. I'm doing this all myself with only internet education lol. I just do t understand if each array can be up to 150vdc, or is that the total maximum all arrays should equal?
What I currently wired I'm now reading it's wrong, I've yet to flip the switch thank God.
Here's what I did:
1 (6) combiner box
18 Canadian (395w) 46.7v & 10amp
bifacial panels
Wired 3 in series, 6 a5rd rrays
Gave me 144voc

What your doing is exactly what I'm confused about .
I too have have the off grid 12kw growatt inverter.
I'm confused at the basic understanding of how much amps or volts I can have in each array and total.
Here's what I have and how I configured it.
What I have:
1 (6) combiner box
18 Canadian bifacial panels
395w 46.7v 10amps

How I Wired it:
6 arrays
3 panels each connected in series

Is this ok???
Or:
3 arrays with 3 panels in series
and
3 arrays with 3 panels each in parallel?

Or?

Do you have the 150vdc pv array version of the 12kw Growatt or do you have the 250vdc PV array version like I have . I talked directly with the Growatt customer service office in California and they confirmed to me that my 250vdc PV array max voltage is per string and not a combined max voltage for the 2 strings. I am using 2- 6 string combiner boxes 1 for each PV sting to my inverter. If you add another combiner box to your set up it will make it a lot easier to split your array up so it will work well with your inverter. 46.7vdc times 3 equals 140.1 vdc unless you live up north it should be ok my array is set up to have a max of 113.7 vdc and the most I have ever seen is 109.3 I've never had it go over the rated voltage but I do live In south MS and only see temps get into the teens a few times a year.

 

[Kornbread]

Ok you guys are right where I'm very confused about.
And thank u in advance as im a mom of 6 doing this all on my own due to finances and only have YouTube education on solar
??
I have the same growatt inverter 12kw off grid. I'm doing this all myself with only internet education lol. I just do t understand if each array can be up to 150vdc, or is that the total maximum all arrays should equal?
What I currently wired I'm now reading it's wrong, I've yet to flip the switch thank God.
Here's what I did:
1 (6) combiner box
18 Canadian (395w) 46.7v & 10amp
bifacial panels
Wired 3 in series, 6 a5rd rrays
Gave me 144voc

What your doing is exactly what I'm confused about .
I too have have the off grid 12kw growatt inverter.
I'm confused at the basic understanding of how much amps or volts I can have in each array and total.
Here's what I have and how I configured it.
What I have:
1 (6) combiner box
18 Canadian bifacial panels
395w 46.7v 10amps

How I Wired it:
6 arrays
3 panels each connected in series

Is this ok???
Or:
3 arrays with 3 panels in series
and
3 arrays with 3 panels each in parallel?

Or?

There are to versions of the spf12000t, one with 150v max Voc, the other 250v max Voc. From what I could gather, you have the 150v version. 144v is very close to the upper limit of the SCC's max Voc input. Somewhere on the panels datasheet, there should be a (cannot remember what it is called) a coefficient to multiply the stated Voc of the panel vs temperature. This will tell you how much higher the pv panel's Voc rises in cold temperatures.

 

[hotrod]

With a quick glance you can see for instance that at 0*C you should assume 110% of your arrays rated open circuit voltage, and at -25*C you should assume 120% of your arrays rated Voc.

 

[kromc5]

With a quick glance you can see for instance that at 0*C you should assume 110% of your arrays rated open circuit voltage, and at -25*C you should assume 120% of your arrays rated Voc.

It's definitely going way over and the 12k units do not warn you of this, the charge controllers will send an audible tone when its getting close.

 

[godsglory22]

Do you have the 150vdc pv array version of the 12kw Growatt or do you have the 250vdc PV array version like I have . I talked directly with the Growatt customer service office in California and they confirmed to me that my 250vdc PV array max voltage is per string and not a combined max voltage for the 2 strings. I am using 2- 6 string combiner boxes 1 for each PV sting to my inverter. If you add another combiner box to your set up it will make it a lot easier to split your array up so it will work well with your inverter. 46.7vdc times 3 equals 140.1 vdc unless you live up north it should be ok my array is set up to have a max of 113.7 vdc and the most I have ever seen is 109.3 I've never had it go over the rated voltage but I do live In south MS and only see temps get into the teens a few times a year.

I do have the 12kw 150vdc
So doing my current set up of,
6 arrays, 1 combiner
3 panels each array wired in series,
Total equaling 140 vdc each array,
will work?

 

[godsglory22]

It's definitely going way over and the 12k units do not warn you of this, the charge controllers will send an audible tone when its getting close.

I do have the 12kw 150vdc

So doing my current set up of,

6 arrays, 1 combiner

3 panels each array wired in series,

Total equaling 140 vdc each array,

will work?

 

[kromc5]

I do have the 12kw 150vdc

So doing my current set up of,

6 arrays, 1 combiner

3 panels each array wired in series,

Total equaling 140 vdc each array,

will work?

For your area look up the average temperatures if you going below 40f then your taking a chance of damaging the capacitors on the main board.

 

[godsglory22]

For your area look up the average temperatures if you going below 40f then your taking a chance of damaging the capacitors on the main board.

Well Colorado, on the plains, we have mild winter days, not too many under 40 during the day,
What if I do
2 in series, and the 3rd in parallel on each of the 6 arrays?
Can you even do that?
Does that work on each array?
Giving me 95vdc?
Or is that too low to operate you think?

 

[hotrod]

I do have the 12kw 150vdc

So doing my current set up of,

6 arrays, 1 combiner

3 panels each array wired in series,

Total equaling 140 vdc each array,

will work?

You should purchase another 6 string combiner box so you can split your array up into two strings 1 for each pv input on your 12kw Growatt inverter. 1 combiner box would have 2 panels in series and 5 strings going to it and the other combiner box would have 2 panels in series 4 strings going to the second combiner box. This way would keep your pv voltage under 100 vdc.

 

[kromc5]

Well Colorado, on the plains, we have mild winter days, not too many under 40 during the day,
What if I do
2 in series, and the 3rd in parallel on each of the 6 arrays?
Can you even do that?
Does that work on each array?
Giving me 95vdc?
Or is that too low to operate you think?

Our panels are very similar, neither of my 150v growatts would function on 2s. Growatt logged in via the wifi dongle to confirm that it was not enough power. You can try 2s and see if it works but if you have already wired the panels then you could do the same as me and install a 250v charge controller. My growatt inverters have run fine for 7 months with no pv or ac input.