I have 14 panels at 545w each which equates to 7630Kw but am only able to generate a max of 3Kw on a clear day at this time of year. I am wondering if they are wired in optimally and could use any advice.

I am in Cape Town and there are 6 panels facing North East and 8 panels facing South West. They are on one string going to the inverter. At peak time all the panels are in the sun but the angle to the 8 panels is not ideal.

My DC voltage is about 260vDC.

Any suggestions on how best they should be connected will be most welcome.

You please need to provide as much info as possible, like Current specs of inverter, mppt ranges,  max watts pv inputs etc etc.

Paste some pics of setup too, thanks

People will need this to check.

Edited May 22, 20233 yr by Eurard

The orientation of those 8 facing SW is not ideal at all and will hamper the production of the 6 facing north. Especially as they are all on the same string 

Edited May 22, 20233 yr by mzezman

3 hours ago, Stu_D said:

I have 14 panels at 545w each which equates to 7630Kw but am only able to generate a max of 3Kw on a clear day at this time of year. I am wondering if they are wired in optimally and could use any advice.

If your panels are in series in only one string then any panel that is in the shade will shut down the whole operation. You must wire your panels into a number of parallel strings for redundancy. eg: Have 3 separate strings, one string for morning, one for midday and one for afternoon - facing in the appropriate direction. With parallel strings it is important that you have a fuse on the +ve of each string.

Edited May 22, 20233 yr by TonyB

10 minutes ago, TonyB said:

If your panels are in series in only one string then any panel that is in the shade will shut down the whole operation. You must wire your panels into a number of parallel strings for redundancy. eg: Have 3 separate strings, one string for morning, one for midday and one for afternoon. With parallel strings it is important that you have a fuse on the +ve of each string.

As mentioned earlier the SW panels are like a tap only partially open and will be blocking a descent current to flow through them. 

Also during the day when there is light then 260V is very low for 14 panels in series. 

We need to know the inverter used in order to advise as suggested to create 3 strings in different direction. Also the current Imp of the panels to work out if one can use 2 to 3 parallel strings. 

Also roof space in different directions would help for a better guidance. 

8 minutes ago, Scorp007 said:

Also during the day when there is light then 260V is very low for 14 panels in series. 

Yip, if some panels are in the shade they become a large resistor!

This creates a 40% drop. 

@Stu_D Bear in mind that by going parallel you will be reducing the voltage but increasing the amperage. You'll need to check your wiring, and your charge controller, to see if they can handle that. You may need to beef them up somewhat.

Edited May 22, 20233 yr by TonyB

I have a Deye 8Kw inverter that can handle two strings. Currently I suspect there are two series strings - one with 6 panels and one with 8 panels that are then paralleled before into one string before entering the inverter. This would be the reason why the voltage is the lower of the two at +_250vDC. (6 X 41v).

12 minutes ago, Stu_D said:

I have a Deye 8Kw inverter that can handle two strings. Currently I suspect there are two series strings - one with 6 panels and one with 8 panels that are then paralleled before into one string before entering the inverter. This would be the reason why the voltage is the lower of the two at +_250vDC. (6 X 41v).

Ah yes, I would separate them, one to each input. 

16 minutes ago, Stu_D said:

I have a Deye 8Kw inverter that can handle two strings. Currently I suspect there are two series strings - one with 6 panels and one with 8 panels that are then paralleled before into one string before entering the inverter. This would be the reason why the voltage is the lower of the two at +_250vDC. (6 X 41v).

The 250V seems correct as indicated. I would put each string on its own MPPT and you will see the output from each one. This will also allow each one to deliver it's best output during the day. SW will be bad this time of the year. 

@TonyB

You beat me to a reply 😀😀

Edited May 22, 20233 yr by Scorp007

Thank you - Will have a chat with the installer about using two separate strings. Makes a lot of sense.

 

11 minutes ago, Stu_D said:

Thank you - Will have a chat with the installer about using two separate strings. Makes a lot of sense.

Hopefully you can monitor each strings performance going forward then and see what's up. Given that they are already in parallel, separating them may not show a massive improvement sadly. Because if one string becomes shaded it just becomes a resistor. The other string should still be operating fine. I suspect that your SW facing ones are the real problem (apart from it being winter), as @Scorp007 says.

Edited May 22, 20233 yr by TonyB

So I had the installer separate the panels onto two strings so I have PV1 and PV2. At 12:00 midday I get 2,2Kw coming from the 6 NE panels and only 900w coming from the 9 SW facing panels. All the panels have good sunshine at this time of the day. I cant understand why the SW panels output is so low since even though the angle is not ideal they are still in the sun. On the 6 panels I get 230v and 10.1 Amps. On the 9 panels I get 337v at 2.8 Amps.

Can anyone help? Do I have a faulty panel?

Hi Stu_D

What make is your panels?

Edited May 29, 20233 yr by krugerjq

24 minutes ago, krugerjq said:

Hi Stu_D

What make is your panels?

Canadian solar 545w

On 2023/05/28 at 12:11 PM, Stu_D said:

So I had the installer separate the panels onto two strings so I have PV1 and PV2. At 12:00 midday I get 2,2Kw coming from the 6 NE panels and only 900w coming from the 9 SW facing panels. All the panels have good sunshine at this time of the day. I cant understand why the SW panels output is so low since even though the angle is not ideal they are still in the sun. On the 6 panels I get 230v and 10.1 Amps. On the 9 panels I get 337v at 2.8 Amps.

Can anyone help? Do I have a faulty panel?

It is pretty normal. It's not just to be in the sun that matters. Panels work best when sun hit them perpendicular and the angle on the SW panels is very far from perpendicular and that is the reason for only 2.8A. It could pick up a bit later in the afternoon but don't expect much power from them. 

Fit as many as you can on the NE string and the rest on the SW string. 

Edited May 29, 20233 yr by Scorp007

On 2023/05/28 at 12:11 PM, Stu_D said:

I cant understand why the SW panels output is so low since even though the angle is not ideal they are still in the sun.

@Scorp007is correct, you can't expect too much from the South facing panels, especially at this time of year when the sun is setting North of West. You could expect a bit more output from them in the afternoons from September onward as the sun starts to set further South.

20 hours ago, Scorp007 said:

On the 6 panels I get 230v and 10.1 Amps. On the 9 panels I get 337v at 2.8 Amps.

6x38=228V

9*38=342V

I've rounded the above a little to make it easier, but at least as far as voltage is concerned it seems you don't have a faulty panel... the lower amps is because of the panel angle and orientation as scorp mentioned.

Thank you all. It is indeed everything to do with the Panel orientation. I must say I am surprised just how bad it is. Im going to have to get more panels for the NE string. I did some checking and it seems that Canadian solar 545w panels are very scarce in Cape Town. Not sure if anyone knows of anyone that has stock?

6 hours ago, Stu_D said:

Thank you all. It is indeed everything to do with the Panel orientation. I must say I am surprised just how bad it is. Im going to have to get more panels for the NE string. I did some checking and it seems that Canadian solar 545w panels are very scarce in Cape Town. Not sure if anyone knows of anyone that has stock?

While you indicating you want more for the NE side why don't you just move a few from the SW under performing side to NE for a better yield? 

Keep say 6 on the SW side and up to 9 on the NE side. 

1 minute ago, Scorp007 said:

While you indicating you want more for the NE side why don't you just move a few from the SW under performing side to NE for a better yield? 

Keep say 6 on the SW side and up to 9 on the NE side. 

The SW panels come into action during the summer afternoons - They are a big boost then as the sun goes down that side and I have a pool heat pump that sucks a lot of energy.

6 minutes ago, Stu_D said:

The SW panels come into action during the summer afternoons - They are a big boost then as the sun goes down that side and I have a pool heat pump that sucks a lot of energy.

OK. You will know better how the 2 strings perform. It just seems like a lot of power can be generated during the course of the day on the NE side. Will the heat pump not be able to use this power during the day? 

2 minutes ago, Scorp007 said:

OK. You will know better how the 2 strings perform. It just seems like a lot of power can be generated during the course of the day on the NE side. Will the heat pump not be able to use this power during the day? 

Yes it will but I can run the heatpump longer with the combination of NE and SW panels in summer.

1 hour ago, Stu_D said:

Yes it will but I can run the heatpump longer with the combination of NE and SW panels in summer.

Usually you set a solar system up to perform adequately in winter. Summer then shouldn't be a problem. Your panels set up for summer will perform very poorly in winter as you have seen.

So here is the latest… I now have 12 panels facing North on one string. (2 series strings in parallel) and 6 panels facing South in a series string. 
A new problem appears to be that the North string is reaching the maximum current of 20Amps and then pegging out. 
I can solve this by splitting the 2 strings to have 9 panels each with both strings having 6 North panels and 3 South panels. 
I am wondering if this will affect the output as the south panels may drag the north panels down.