What is better for best performance of a high voltage inverter, more volts or amps? i Have 12x330w panels, 38voc and 9A each. Do i arrange them in 3 strings of 4 panels(series) per string (152v at 9A) or 6 panels per string (228v at 9A) series then paralleled for total 152v at 27A or 228v at 18A. 450voc at 100A inverter.

Edited July 5, 20232 yr by Off Grid Farmer
better explanation

Your inverter spec sheet should indicate the optimal voltage to use, arrange the panels according to that.
e.g. sunsynk 5kW
PV Input Voltage 370Vd.c (125Vd.c ~ 500Vd.c) the 370V is where the mppt works at it's most efficient point

32 minutes ago, WannabeSolarSparky said:

Your inverter spec sheet should indicate the optimal voltage to use, arrange the panels according to that.
e.g. sunsynk 5kW
PV Input Voltage 370Vd.c (125Vd.c ~ 500Vd.c) the 370V is where the mppt works at it's most efficient point

This is exactly it, also make sure you do not exceed the voltage of your MPPT / PV input as that can cause damage.

Also keep in mind that excess current could cause some issues with the inverter or cause the inverter to clip the excess current which would mean you are not able to use the full amount of power being generated by the panels.

 

The correct voltage is would what lead to better efficiency if that is what you are asking.

My Mppt input on the inverter says 450voc at 100A so I'm still well below the max if i re-wire the panels for 2 strings of 6 panels each then parallel to end up with 228V 18A. i Was looking for that nominal voltage point. I'm planning to add more panels soon if the price of solar panels don't go up to much. Thank you for your replies guys.

If your Inverter is a Growatt 5000ES then your max is 22A from the panels, anything above that will be clipped.
The 100A is the max charge current not the max panel current.

19 minutes ago, Off Grid Farmer said:

My Mppt input on the inverter says 450voc at 100A so I'm still well below the max if i re-wire the panels for 2 strings of 6 panels each then parallel to end up with 228V 18A. i Was looking for that nominal voltage point. I'm planning to add more panels soon if the price of solar panels don't go up to much. Thank you for your replies guys.

Please state the name, the make and model of your inverter, or post a pic of the datasheet or plaque on the side of it.

My concern is that you might be mis-reading the specs. Just basics - 450V x 100A says you've got a 45-kiloWatt MPPT input, which doesn't sound right for a panel set of just 12x330W, or just under 4kW. You're out by a factor of 10, and possibly thinking you're way under when you're not. Just comparing to the typical Sunsynk 5kW inverter, there's a 13A panel current input, while though the charge current being output to the battery is 100A.

Basically what  @zsde said. He just beat me to the punch, but then i couldn't stop mid-sentence and had to repeat it just to re-inforce the point. Sorry.

6 minutes ago, GreenFields said:

Please state the name, the make and model of your inverter, or post a pic of the datasheet or plaque on the side of it.

My concern is that you might be mis-reading the specs. Just basics - 450V x 100A says you've got a 45-kiloWatt MPPT input, which doesn't sound right for a panel set of just 12x330W, or just under 4kW. You're out by a factor of 10, and possibly thinking you're way under when you're not. Just comparing to the typical Sunsynk 5kW inverter, there's a 13A panel current input, while though the charge current being output to the battery is 100A.

Basically what  @zsde said. He just beat me to the punch, but then i couldn't stop mid-sentence and had to repeat it just to re-inforce the point. Sorry.

The max panel current is 22A as you said on my Growatt spf 5000es. So does this mean the total of the series strings then parallel to inverter can not exceed 22A?

2 minutes ago, Off Grid Farmer said:

inverter can not exceed 22A?

It can within a reasonable amount, the Amps above 22 will just be clipped, i.e. you will loose some of the potential energy on sunny days, but you will have higher yield on days that are cloudy.
My 2 parallel strings add up to ~26Amps and I have the same Inverter and it just flatlines at 22A. Although my panels are potentially 6400W, the max I can draw from them is around 5600W due to the 22A limit and the 6S giving me a VOC of ~300V but under load they are always around 230-250 and in idle around 270V.

So it's a trade off. Stay within the max voltage range. Excess voltage is the killer. Oversizing on the Amps (within limits) improves potential yield on less stellar days.

 

12 minutes ago, Off Grid Farmer said:

The max panel current is 22A as you said on my Growatt spf 5000es. So does this mean the total of the series strings then parallel to inverter can not exceed 22A?

Correct, if you have that model inverter.
Best is to say what inverter you have and model.

7 minutes ago, zsde said:

It can within a reasonable amount, the Amps above 22 will just be clipped, i.e. you will loose some of the potential energy on sunny days, but you will have higher yield on days that are cloudy.
My 2 parallel strings add up to ~26Amps and I have the same Inverter and it just flatlines at 22A. Although my panels are potentially 6400W, the max I can draw from them is around 5600W due to the 22A limit and the 6S giving me a VOC of ~300V but under load they are always around 230-250 and in idle around 270V.

So it's a trade off. Stay within the max voltage range. Excess voltage is the killer. Oversizing on the Amps (within limits) improves potential yield on less stellar days.

 

So i can change the panel strings to 6 panels in series that gives me 228Voc and 9A and the other string the same and that will give me 228Voc at 18A together?

1 minute ago, Off Grid Farmer said:

So i can change the panel strings to 6 panels in series that gives me 228Voc and 9A and the other string the same and that will give me 228Voc at 18A together?

Sounds perfect to me

 

1 minute ago, zsde said:

Sounds perfect to me

 

Thanks. I'm use to my other system is the old separate charge controller and inverter.

59 minutes ago, Off Grid Farmer said:

The max panel current is 22A as you said on my Growatt spf 5000es. So does this mean the total of the series strings then parallel to inverter can not exceed 22A?

That equates to 9.9kw of panels. Panels in series requires less copper(thinner wires) at higher voltage rather than higher current. It is like power transmission high voltage at the generating units that gradually steps down to end user consumption. The only hazard with high voltage Mppt is arc fault on loose connections so care must be taken to secure all cabling properly on combiners and use adequate fuse and spd protection. Sunsynk inverters can detect arc fault that causes noise on the line F63 error code.

Great reading ...I'm interested in the ,rated current 120A ,is this what it can accept or what it puts out ?

I have 12 panels 550w ,imp current 13.11a, vmp 41.96 ,VOC 49.90,isc14.00a

Should I run 3 strings of 4 panels in series

Or 4 strings of 3 panels in series?

Or will it not matter either way as the mppt controller will take care of business either way ....I used all 200 amps on the inverter  welder the other day and everything worked as it should  on (10mm plate) 

Just trying to optimise and protect the inverter for peace of mind .

Are all your panels on the same orientation?   Eg all face NW and at 20 degree angle.      You must have, per MPPT, all the panels the same orientation.    If half your panels face NE and half NW then you’ll be forced into at least two strings.

1 hour ago, Nepia said:

I'm interested in the ,rated current 120A ,is this what it can accept or what it puts out ?

That is output current from the mppt.

1 hour ago, Nepia said:

Should I run 3 strings of 4 panels in series

That would be at the max Voc input of the inverter so no not 4 in series.

1 hour ago, Nepia said:

4 strings of 3 panels in series?

That would be good then Voc 50v below max Voc of Mppt

Edited July 20, 20241 yr by TaliaB

Thankyou very much 👍my mind is at ease 🙏

1 hour ago, macafrican said:

Are all your panels on the same orientation?   Eg all face NW and at 20 degree angle.      You must have, per MPPT, all the panels the same orientation.    If half your panels face NE and half NW then you’ll be forced into at least two strings.

Yes all panels are on the same orientation facing north . However they are bifocals,but just using them normally for now....thanks 

Just now, Nepia said:

Yes all panels are on the same orientation facing north . However they are bifocals,but just using them normally for now....thanks 

*Bifacils

Just now, Nepia said:

Bifacial

 

On 2024/07/20 at 4:10 PM, TaliaB said:

That is output current from the mppt.

That would be at the max Voc input of the inverter so no not 4 in series.

That would be good then Voc 50v below max Voc of Mppt

I'm now curious as I'm learning more.......if the preferred vmp voltage is 60-105v ...would bumping up the amps be more advantageous by running 6 strings of 2 in series?

1 minute ago, Nepia said:

I'm now curious as I'm learning more.......if the preferred vmp voltage is 60-105v ...would bumping up the amps be more advantageous by running 6 strings of 2 in series?

Or would the extra amps just be wasted/ not used ?

On 2024/07/20 at 3:22 PM, macafrican said:

Are all your panels on the same orientation?   Eg all face NW and at 20 degree angle.      You must have, per MPPT, all the panels the same orientation.    If half your panels face NE and half NW then you’ll be forced into at least two strings.

I'm interested in more information about this type array could 4 strings work better or worse 

On 2024/07/22 at 12:47 PM, Nepia said:

I'm interested in more information about this type array could 4 strings work better or worse 

Your inverter can charge a maximum of 5800W. Thus you can use 4 east and 4xwest in 4 strings. Thus you waste 1400W that the inverter can use. This based on the 550W panels you indicated on the other topic. 

I would choose a different panel to get closer to 5800W from groupings of 4. 12 x 455/465/470W if you have space. 

On 2024/07/20 at 4:10 PM, TaliaB said:

That is output current from the mppt.

That would be at the max Voc input of the inverter so no not 4 in series.

That would be good then Voc 50v below max Voc of Mppt

Today I did some testing .

To date I've only been running 1 string with two panels in series... while I'm still exploring where and how I'm going  to mount my other 10 panels.... This has been running 96volts around 12amps.

So First i tested the 1 string with three panels in series ....at 115 volts (earlier morning ) the fans kept switching on and off.( Zero load)

Then I went to 2 strings with two panels in series on each string.....the volts hovered around the mid 90s ...and around 24amps dropping up and down regularly ...and the fans stayed off .

At this time my wife had started cooking so not the best time I guessed to keep testing.

From what I've tried so far the inverter prefers to be happy at the 105volts as per the label on its cabinet.

Will carry on testing tomorrow if I can ( with pics)