Growatt 6KW inverters and over paneling

[terrango]

Before i start... i search the forum and i saw a lot of back and fourth on yes over panel and no.

I have 3 6KW Growatt inverters. Right now all 3 inverters are have about 3kw of solar attached.
I just finished building a new solar mount and i want to max out these units.
My max PV for this units are 5000W in 1 solar input.
My input voltage is sitting around 180-190V well under the max 245V.
The total current from the arrays (40amps maybe slightly under that).
I have a very large battery bank about 1500 amps.
Now Signature solar stated i could over panel these inverters by up to 20%.

My plan was to increase from 3000w to 5600w of solar. S0 about 12% over.
In summer even at max sun i was always producing 2.4kw out of 3Kw.

So what do you guys think, will it be an issue adding a bit more power?
Thanks

 

[Northernchateau]

I have 3 6KW Growatt inverters. Right now all 3 inverters are have about 3kw of solar attached.

Are you saying each inverter has 3kw attached? Or each inverter has 1kw attached for a total 3kw
Also what are the panel specs and how are the configured/connected?

My max PV for this units are 5000W in 1 solar input.
My input voltage is sitting around 180-190V well under the max 245V.

The Max listed voltage is normally VOC. There should also be a operating Range listed of that unit, what is it?

Now Signature solar stated i could over panel these inverters by up to 20%

My plan was to increase from 3000w to 5600w of solar.

5000 x 1.2 (20%)= 6000 watts so 5600 watts will be ok ad long as the operating voltage and current are not exceeded

 

[BentleyJ]

5000 x 1.2 (20%)= 6000 watts so 5600 watts will be ok as long as the operating voltage and current are not exceeded

Voltage and Current need to be considered in slightly different ways. The Max voltage rating of the SCC input should never be exceeded by the Voc of a series panel array. The SCC "sees" the full voltage of the solar array. 180V to190V is well below the stated 245V limit.
On the other hand, the amount of current that passes through the SCC is determined by the electronics and the MPPT algorithm not the solar panels. Therefore its ok to over panel such that the solar array may be capable of providing more current than the SCC can handle on a sunny day but the SCC will just ignore it, it only uses up the maximum it is capable of. Its called clipping and the potential extra current basically goes to waste. However, on a cloudy day you will get more production which is generally when you need it the most.

 

[Northernchateau]

Voltage and Current need to be considered in slightly different ways. The Max voltage rating of the SCC input should never be exceeded by the Voc of a series panel array. The SCC "sees" the full voltage of the solar array. 180V to190V is well below the stated 245V limit.
On the other hand, the amount of current that passes through the SCC is determined by the electronics and the MPPT algorithm not the solar panels. Therefore its ok to over panel such that the solar array may be capable of providing more current than the SCC can handle on a sunny day but the SCC will just ignore it, it only uses up the maximum it is capable of. Its called clipping and the potential extra current basically goes to waste. However, on a cloudy day you will get more production which is generally when you need it the most.

Any you slice it we need more information as just increasing the PV wattage may cause issues and may be fine.

 

[terrango]

Are you saying each inverter has 3kw attached? Or each inverter has 1kw attached for a total 3kw
Also what are the panel specs and how are the configured/connected?

The Max listed voltage is normally VOC. There should also be a operating Range listed of that unit, what is it?

5000 x 1.2 (20%)= 6000 watts so 5600 watts will be ok ad long as the operating voltage and current are not exceeded

Each inverter has a 3kw string of panels attached to it. Each inverter according to Growatt can handle up to 5000W of solar.
So in theory i should be able to connect up to 15000w between 3 inverters.

My PV input voltage range is 60-245V for the 6 KW inverter.
My VOC for my panels are 151.68V with 128.16v at the inverter.
So i do have a lot of room before i hit the max input voltage of 245.
I am using hanwha Q cells 480w panels. they perform really well and i seem to be able to get a good deal on them.
I have another skid of 30 panels coming and would like to max out the inverters if possible.

 

[Northernchateau]

Each inverter has a 3kw string of panels attached to it. Each inverter according to Growatt can handle up to 5000W of solar.
So in theory i should be able to connect up to 15000w between 3 inverters.

My PV input voltage range is 60-245V for the 6 KW inverter.
My VOC for my panels are 151.68V with 128.16v at the inverter.
So i do have a lot of room before i hit the max input voltage of 245.
I am using hanwha Q cells 480w panels. they perform really well and i seem to be able to get a good deal on them.
I have another skid of 30 panels coming and would like to max out the inverters if possible.

I do not know exactly which Growatt you have but the specs I just looked at show 60-245 volts working Max VOC 250.
That being said you can not run panels in series as 151.68v x 2 = 303.36v, that's 53 volts over the VOC spec limit.
Now lets do some more math, 5000 / 480 w = 10.41 panels
10 panels x 480w/128.16v = 30.75 amps well withing the Growatt limits
Please post a pic of the label on the panel just so we are speaking the same lingo but
if my math is right you need to run 1S30P configuration.

 

[terrango]

I do not know exactly which Growatt you have but the specs I just looked at show 60-245 volts working Max VOC 250.
That being said you can not run panels in series as 151.68v x 2 = 303.36v, that's 53 volts over the VOC spec limit.
Now lets do some more math, 5000 / 480 w = 10.41 panels
10 panels x 480w/128.16v = 30.75 amps well withing the Growatt limits
Please post a pic of the label on the panel just so we are speaking the same lingo but
if my math is right you need to run 1S30P configuration

I will post of photo of the label on the panels later when i get home.
Here is a link to the spec sheet: https://www.q-cells.us/dam/jcr:a842...EAK_DUO_XL-G10.2_470-495_2022-01_Rev03_NA.pdf
I have the 480w panels.
My idea was to rewire to 4 panels in series x 3 in parallel. giving a VOC of 202.24V and amps of 34a.
The total wattage would be 5760w per inverter
or stay with my 3 panels in series x4 parallel giving a VOC 151.68V and just under 40a and total PV watts 5760.
Here is my inverter specs

 

[BentleyJ]

4 in series is better, it reduces the amount of wiring and with the higher voltage the array will reach the minimum startup volts earlier in the morning. Also, the higher voltage will result in lower input amperage and potentially reduce the tendency for clipping since you will be over paneled. It depends on the maximum input amps listed on the datasheet for the inverter.

 

[Quattrohead]

Yeah your hard limit is 4 in series for those panels and inverter. 55 voc x4 = 220v PV input. 5 might be ok if you are feeling brave in a hot country.
Those panels are not a great match for those inverters so maybe a separate mppt charger that is more suited?

 

[terrango]

Max PV charge current is 80A.
I dont have smaller panels but i do have access to a lot of the larger panels.

These are the solar charge controller specs on my unit.

 

[Northernchateau]

I will post of photo of the label on the panels later when i get home.
Here is a link to the spec sheet: https://www.q-cells.us/dam/jcr:a842...EAK_DUO_XL-G10.2_470-495_2022-01_Rev03_NA.pdf
I have the 480w panels.
My idea was to rewire to 4 panels in series x 3 in parallel. giving a VOC of 202.24V and amps of 34a.
The total wattage would be 5760w per inverter
or stay with my 3 panels in series x4 parallel giving a VOC 151.68V and just under 40a and total PV watts 5760.
Here is my inverter specs

Ok now I understand my confusion so let me try solar math again:
VOC 53.61 x 4 panels in series = 214.44 volts
Vmp 44.81 x 4 panels in series = 179.24 volts
Imp 10.71 x 3 series sets in parallel = 32.12 amps
480 watts x 12 panels = 5,760 watts
Always go with the highest voltage as that yield the lowest current, lowest voltage drop in the wire and smallest wire size.
Remember
Panels in series, add all the panels in the string voltages together, works for both Vmp or VOC but don't mix the 2 as they are 2 different things.
Panels in parallel, add all the string currents (Imp) together.

 

[octal_ip]

Max PV charge current is 80A.
I dont have smaller panels but i do have access to a lot of the larger panels.
View attachment 119103
These are the solar charge controller specs on my unit.

Just be careful, that's the current on the battery charger side, not the MPPT side. The maximum current for the MPPT and therefore the solar panels will be much lower, in the 20 - 30 amp range, depending on the model.

 

[terrango]

OK thanks for the advice everyone and sorry for the confusion.
Ill change the strings up in spring when its warmer out.

 

[terrango]

Got one more question.
So i have 2 of these units also. What do you recommend for a panel setup with the same 480w panels?
I was thinking 2 series, 4 parallel. But would i be able to 2 series, 5 parallel or would that be too much for this unit to handle?

 

[Northernchateau]

Got one more question.
So i have 2 of these units also. What do you recommend for a panel setup with the same 480w panels?
I was thinking 2 series, 4 parallel. But would i be able to 2 series, 5 parallel or would that be too much for this unit to handle?

VOC 53.61 x 2 panels in series = 107.22 volts
Vmp 44.81 x 2 panels in series = 89.62volts
Imp 10.71 x 4 series sets in parallel = 42.84 amps
480 watts x 8 panels = 3840 watts
Imp 10.71 x 5 series sets in parallel = 53.55amps
480 watts x 10 panels = 4,800 watts
Either set-up will work. That unit is rated for 4500 watts so 4800 watts will be 6% over panel but that should not be a problem.
The only thing you need to make sure you do it use the right size wire from your combiner box to the inverter.
If you post how long the wires will be I will show you the calculation and wire size recommendation.

 

[terrango]

Thanks for the info.
I havent started making a plan for this install.
I am revamping my battery banks, but when i do ill definitely reach out. Thanks