Panels underperforming or another limiting factor? I'm new!!!

[Savvoh]

Hello everyone. 

Just installed a 8kw SunSynk, 5kw battery and 6 x 550 or 555 watt panels in a line on my north facing roof. Its two stories up so not much shading.  

The battery and inverter seem to be working well and playing with the settings to try minimize grid power has been much fun. 

However during the day my panels at any stage only seem to reach max 2.2kw. I even try and force more load onto them to peak higher, but cant seem to get more juice. 

Question:

- Is there a chance that 2 of them are faulty?
- Is there any limiting factor that could be preventing them from performing on my inverter?
- Did i get hoodwinked and get sold 350w panels even though they seem to big for those :0
- Or is there something that I am missing completely?
This is a graph of what i am trying to explain, between about 11:30 and 12:30 i ran my geyser to try and see if i could suck more watts out of the panels. 

But to no avail. As u can see my general PV output is never more then 2.1 kw all day. 

Any advice would be amazing. 

Thanks, Sav

Edited May 18, 2023 by Savvoh

[Pumba]

That 8 kw Sunsynk needs 9 of those panel on one MPPT to give reasonable PV power. I have 8 of those panels on a 5 kW Sunsynk on one MPPT (east facing)

[Scorp007]

1 hour ago, Pumba said:

That 8 kw Sunsynk needs 9 of those panel on one MPPT to give reasonable PV power. I have 8 of those panels on a 5 kW Sunsynk on one MPPT (east facing)

9 panels would seem the maximum you can use on this inverter per MPPT. 

The inverter/panels combination should perform better. A friend op mine is currently getting about 1500W from only 4x455W with the same inverter. Those panels started early in the morning so no problem to get the MPPT working. 

Not knowing the area or the angle my estimate with high load it could go to about 2.7kW.

If the OP could supply the rating plate of the panels and the angle with area it would help as a starting point. 

Edited May 18, 2023 by Scorp007

[Savvoh]

Thanks for the replies. I do appreciate it. 

OK here is what I've got so far. 

Panel placement, directly North and i can only assume my roofs tilt is around 30%. I'm in Johannesburg. This was taken at 11:00, so the most shading that can occur is done. 

Panel stats, they the PNG144M-555 at the end

This is my max PV input at any time. 

This is my PV box thingy, im not sure if this could limit anything. 

Things I have tried:

- Moved the PV to priorities load, as i thought the max charge on my battery of 50A may have been the cause.

-  Checked the max Solar Power setting is 9000W. 

- Scratched my head a lot and watched YouTube videos and tried to find any solutions. 

Here are a couple more snaps of my settings incase this means anything. 

Appreciate any help i can get. 

Shot, Sav. 

[ZaydS]

I have 6.5kw panels that generates 4.5kw peak on a reasonable winter's day. They are split into 2 strings - 2/3 NNE and 1/3 NNW. That's about 70% of installed capacity.

So, I don't think your PV production is a problem as you getting about 2.2kw from 3.3kw panels.

My graph for yesterday. I'm in Cape Town.

 

Edited May 19, 2023 by ZaydS

[FixAMess]

Rule of thumb: Watts per day = 4 x installed PV in Winter, 5-6 times in summer, depending on location, temp, weather etc.

What is your daily production, not peak?

On 6000W installed PV, I'm getting max 25kWh per day now...N Facing at 22 degrees, JHB.

You should be getting 13kWh per day approximately if you're in JHB area.

Also remember that your panels will only provide enough to supply the load. If load (battery+essential) + Non-essential if configured is 100W, your panels will only produce 100W...

Try increasing your load at midday, kettle, mwave, etc and see if your pv output follows the load.

[Scorp007]

39 minutes ago, Savvoh said:

Thanks for the replies. I do appreciate it. 

OK here is what I've got so far. 

Panel placement, directly North and i can only assume my roofs tilt is around 30%. I'm in Johannesburg. This was taken at 11:00, so the most shading that can occur is done. 

Panel stats, they the PNG144M-555 at the end

This is my max PV input at any time. 

This is my PV box thingy, im not sure if this could limit anything. 

Things I have tried:

- Moved the PV to priorities load, as i thought the max charge on my battery of 50A may have been the cause.

-  Checked the max Solar Power setting is 9000W. 

- Scratched my head a lot and watched YouTube videos and tried to find any solutions. 

Here are a couple more snaps of my settings incase this means anything. 

Appreciate any help i can get. 

Shot, Sav. 

What is weird is that 2 strings are shown with their fuses. Being 6 panels they should be in series and connected to 1 MPPT. 

What is not shown is the voltage going to the MPPT? 

[mzezman]

25 minutes ago, Scorp007 said:

What is weird is that 2 strings are shown with their fuses. Being 6 panels they should be in series and connected to 1 MPPT. 

What is not shown is the voltage going to the MPPT? 

Good catch there...

[Savvoh]

38 minutes ago, FixAMess said:

Rule of thumb: Watts per day = 4 x installed PV in Winter, 5-6 times in summer, depending on location, temp, weather etc.

What is your daily production, not peak?

On 6000W installed PV, I'm getting max 25kWh per day now...N Facing at 22 degrees, JHB.

You should be getting 13kWh per day approximately if you're in JHB area.

Also remember that your panels will only provide enough to supply the load. If load (battery+essential) + Non-essential if configured is 100W, your panels will only produce 100W...

Try increasing your load at midday, kettle, mwave, etc and see if your pv output follows the load.

Busy testing that at the moment, but the flat line is what is concerning me, not even like a little hows ur mother ill give you 2.6 for a minute or 2. I get the same performance at 11:00 as 13:30, i will carry on pushing to later through the day, but seems to be flatlining like a champion. :0 

28 minutes ago, Scorp007 said:

What is weird is that 2 strings are shown with their fuses. Being 6 panels they should be in series and connected to 1 MPPT. 

What is not shown is the voltage going to the MPPT? 

That sir I'm afraid i don't know how to answer... Is there a setting or something i should be looking at or something i can do?

Or is this something i need to ask the installer?

Edited May 19, 2023 by Savvoh

[PearlJam]

38 minutes ago, Scorp007 said:

What is weird is that 2 strings are shown with their fuses. Being 6 panels they should be in series and connected to 1 MPPT. 

What is not shown is the voltage going to the MPPT? 

..and based on the system flow chart screenshot only MPPT1 is giving power

[mzezman]

2 minutes ago, PearlJam said:

..and based on the system flow chart screenshot only MPPT1 is giving power

the panels are only connected to MPPT1 - 2 is free and unused at the moment

[Eurard]

Eish move your dish, you are also literally losing some of that panel, and since it is Series, I assume, maybe more, same with the last panel bottom.

[Savvoh]

2 minutes ago, Eurard said:

Eish move your dish, you are also literally losing some of that panel, and since it is Series, I assume, maybe more, same with the last panel bottom.

Will get back up there and take it off tomorrow. Thanks.  

[Scorp007]

3 minutes ago, mzezman said:

the panels are only connected to MPPT1 - 2 is free and unused at the moment

So for this topic the 2.1kw produced is very good. 

I would bridge string 2 in series with 1 to use them as 6. Output will be higher. 

[P1000]

It looks like the string is split in 2 and connected in parallel to one MPPT. That would explain the flatline - the current is clipping.

Edited May 19, 2023 by P1000

[Eurard]

48 minutes ago, Savvoh said:

Will get back up there and take it off tomorrow. Thanks.  

Just move your panel down 10cm or so. The last panel just move it up 10cm. Yes your OCD will make you run for the hills but at least there is not a single part or part of a cell in shade then.

[spotity]

1 minute ago, Eurard said:

Just move your panel down 10cm or so. The last panel just move it up 10cm. Yes your OCD will make you run for the hills but at least there is not a single part or part of a cell in shade then.

Most people don't use DSTV dishes anymore. Probably the case here, and much easier to remove then try and move the mountings. 

[Savvoh]

4 minutes ago, spotity said:

Most people don't use DSTV dishes anymore. Probably the case here, and much easier to remove then try and move the mountings. 

This is true in my case.  Fiber changed the world.

[Eurard]

47 minutes ago, P1000 said:

It looks like the string is split in 2 and connected in parallel to one MPPT. That would explain the flatline - the current is clipping.

How do you deduct this through the box? Isnt the box just catering for two, but only one is in use?

 

Surely with only 6 x 555 panels: All can be put in series on MPPT 1: 234V x 10.63A = 2487.42W

Or two strings of 3 panels each on MPPT 1 & MPPT2: (117V x  10.63W) x 2 = 2487.42W

 

With start up at 150V, personally I would go 6 in series.

Edited May 19, 2023 by Eurard

[Eurard]

46 minutes ago, P1000 said:

It looks like the string is split in 2 and connected in parallel to one MPPT. That would explain the flatline - the current is clipping.

The current on NOCT is only 10.63 x 2 (if in parallel), why would there be clipping under load?

Edited May 19, 2023 by Eurard

[Eurard]

Hang on:

Okay so you got 2.09kW.

At NOCT with all six in series, you are at best gonna get 2487.42W, consider winter, and a cell or two in shade, the 2.09 actually looks good ???

 

I actually do this to sort of get an idea:

Take Vmp x Imp (STC) x 0.8 (this to sort of get close to NOCT, and then x this by 0.85 for winter.

If I do this to your panels, then 2487.42 (NOCT) x 0.85 (winter) = 2114.307W, which is 24 Watt more than what you are getting.

 

Something tells me you are seeing the 555w and did calculations on 555 x 6 = 3.3kW. You will never get this.

 

I recently bought 8 x 620w panels, and what I am expecting is just north of 3kW this time of year.

 

Mid December I am expecting to get mid to high 4kW's, with the occasional perfect day conditions almost hitting 5kW

Edited May 19, 2023 by Eurard

[Savvoh]

12 minutes ago, Eurard said:

Hang on:

Okay so you got 2.09kW.

At NOCT with all six in series, you are at best gonna get 2487.42W, consider winter, and a cell or two in shade, the 2.09 actually looks good ???

 

I actually do this to sort of get an idea:

Take Vmp x Imp (STC) x 0.8 (this to sort of get close to NOCT, and then x this by 0.85 for winter.

If I do this to your panels, then 2487.42 (NOCT) x 0.85 (winter) = 2114.307W, which is 24 Watt more than what you are getting.

 

Something tells me you are seeing the 555w and did calculations on 555 x 6 = 3.3kW. You will never get this.

 

I recently bought 8 x 620w panels, and what I am expecting is just north of 3kW this time of year.

Thanks for all the replies.  Do appreciate it. The panels are all in series.  One line. 
 

Well in that case I can’t complain.  The maths is to higher grade for me, but makes sense. 
 

I just thought I would see some sort of fluctuation in the mid day range.  And not a flat line.  
 

but I will be happy with what I got cause it’s seems to get to max by 10:30. So can’t complain. 

[Eurard]

8 minutes ago, Savvoh said:

Thanks for all the replies.  Do appreciate it. The panels are all in series.  One line. 
 

Well in that case I can’t complain.  The maths is to higher grade for me, but makes sense. 
 

I just thought I would see some sort of fluctuation in the mid day range.  And not a flat line.  
 

but I will be happy with what I got cause it’s seems to get to max by 10:30. So can’t complain. 

I can tell you that from around 10am to 2pm now I don't see much increase, summer is a different story.

 

If you want to see a little more, just place a spacer between top roof bracket and rail and lift the top edge your panels slightly, a spacer of 10cm should see some improvement.

Edited May 19, 2023 by Eurard

[Savvoh]

Maybe I’ll throw 2 more panels below then horizontally and see if I can get some more juice.  I’m just very short on roof space. Haha. 
 

Thanks everyone.  Appreciate it. 

Edited May 19, 2023 by Savvoh

[PsyCLown]

32 minutes ago, Eurard said:

I can tell you that from around 10am to 2pm now I don't see much increase, summer is a different story.

 

If you want to see a little more, just place a spacer between top roof bracket and rail and lift the top edge your panels slightly, a spacer of 10cm should see some improvement.

This would obviously change the angle.

 

For interest sake, what would the ideal angle be in summer vs in winter?