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East/west solar installation Help

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Hi All

I've got a 5kw Sunsync inverter with a 5.5kw Hubble battery atm to beat load shedding.

However I want to install some panels to help cut my bill Aswell. My roof layout makes it almost impossible to get panels facing North so I will have to do a east/west installation.

 

I was thinking to start out to either opt for 5*540W panels facing east and another 5 facing west. I i cant get hold of 540W I might gou for 6*455W east and another 6 west. I do have roof space left to add more panels later on if needed Im on a budget :). Currently there are nothing that would place any shadows onm y roof space either side.

 

My concern however is would the east west installation with this setup make a noticeable difference? Im currently using about 17Kw/h a day. Already purchased a smart timer for geyser to allow pv to heat that up aswell.

 

Any help would be much appreciated to try and get this setup working as good as possible with my situation.

1 hour ago, Be4dawn said:

My concern however is would the east west installation with this setup make a noticeable difference?

The short answer is yes, especially in winter.

The tables at the top of the graphs below show PV yields (kWh per day per kW installed) for a North facing installation, and one that is a combination of East/West.  Roof angle is assumed at 35 degrees.

What you can see is that the East/West combination is slightly better in January (7.1kWh/day vs 6.8kWh/day, and a flatter distribution) but July is a disaster: 2.5kWh/day for East/West vs 4.9 for North.  Average for the year is about 28% better for North facing panels.

The effect will vary with roof angle (steeper is worse) and latitude: further from the equator is worse.  I can run the graphs for your location / roof angle if you send me the details.

North facing:

image.png.54afa3f2ac29517fb92ab9b7b084cf72.png

 

East/West facing:

image.png.3de0b7e749fae6e0cdfea6aa17117fc2.png

 

@Calvin North facing panels are almost always more productive that an East/West split, the thing to keep in mind with those comparisons is that you are assuming 100% utilisation of the energy that the panels are able to produce. In reality that is very seldom the case as there are very few people who can feed their extra energy back into the grid and batteries are often fully charged early in the day.

Making good energy earlier in the morning and later into the afternoon more than makes up for the slightly lower peak production in my opinion

1 hour ago, Sc00bs said:

@Calvin North facing panels are almost always more productive that an East/West split, the thing to keep in mind with those comparisons is that you are assuming 100% utilisation of the energy that the panels are able to produce. In reality that is very seldom the case as there are very few people who can feed their extra energy back into the grid and batteries are often fully charged early in the day.

Making good energy earlier in the morning and later into the afternoon more than makes up for the slightly lower peak production in my opinion

Fair enough, depending on your requirements.

For many (most?) people the system design is driven by winter demands.  The problem with the East/West configuration is winter - it never produces more power than North facing panels and only half in total.  Look at the curves for July.

Also, 50% less in winter, 28% less annual production stretches my understanding of "slightly lower peak production" 🙄

As long as your east/west panels are spec'd sufficiently to fully charge your batteries in the middle of winter then you should be ok.
My East/West setup are perfectly spec'd for my use case and winter worked out just great, still ended up with excess power.

If however you are going to rely on production feedback to the grid to offset costs then North facing would always be the ideal way to go.

Picking up on this thread:  I currently have 12 x 255W [old] panels, North facing with a Synsynk 5kw. I have no more space on the north facing section and was considering 5 x 540W panels to supplement on available East facing section, wired to the second MPPT of the inverter.  Any thoughts/criticisms on this would be highly appreciated. 

Edited by shovelhead

18 minutes ago, shovelhead said:

Picking up on this thread:  I currently have 12 x 255W [old] panels, North facing with a Synsynk 5kw. I have no more space on the north facing section and was considering 5 x 540W panels to supplement on available East facing section, wired to the second MPPT of the inverter.  Any thoughts/criticisms on this would be highly appreciated. 

Should work perfectly.

42 minutes ago, Be4dawn said:

Would you guys recommend i go for Longi 540W? 

 

ans should i install 12 or can i start with 10?

either 12 or 10 will work just fine, the sunsynk mppt's can easily startup with 4 on each mppt, so 5 or 6 on each will work just fine.

On 2022/09/22 at 10:16 PM, Calvin said:

The short answer is yes, especially in winter.

The tables at the top of the graphs below show PV yields (kWh per day per kW installed) for a North facing installation, and one that is a combination of East/West.  Roof angle is assumed at 35 degrees.

What you can see is that the East/West combination is slightly better in January (7.1kWh/day vs 6.8kWh/day, and a flatter distribution) but July is a disaster: 2.5kWh/day for East/West vs 4.9 for North.  Average for the year is about 28% better for North facing panels.

The effect will vary with roof angle (steeper is worse) and latitude: further from the equator is worse.  I can run the graphs for your location / roof angle if you send me the details.

North facing:

image.png.54afa3f2ac29517fb92ab9b7b084cf72.png

 

East/West facing:

image.png.3de0b7e749fae6e0cdfea6aa17117fc2.png

 

I just got worried about the yields shown.

Then I saw the xxkWh/day should be xxkWh/kW of PV installed per day. 😄😄😄

With the PV lost due to not enough load or batteries full it would not matter if 1 make provides 3% more or less than the other when choosing between different top tier makes.

Edited by Scorp007

  • Author

Just got off the phone with sunsync. They said the 540W panels Amp per kppt is to close and I should rather install panels with a lower current.

  • 1 year later...
  • 1 month later...
  • Author

@shovelhead Sorry man been a while since I was on here, I ended up going for Longi 440W.

 

The NTC on the 550w panels is 13.1 A or something witch is over the max amp rating for the inverter MPPT, Even though it should be fine it will cause the inverter to run hotter when clipping accurs. They told me that they have had inverters come in were the MPPT gave issues. So they don't  recommend going for 540W panels

 

 

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