Choosing panels - by wattage or by size?

[Solo]

I am a trustee on a body corporate with a shared roof.

We are considering solar, and the 2 options are:

1. Body corporate owns the roof.

2. Owners share the roof.

It is likely that Opt 2 will be chosen, due to the complexity of obtaining agreement on Opt 1

My question is, how does one choose the panel size, as the roof space can be better utilised if we use 3 rows of 450W panels vs 2 rows of 550W panels?

Using landscape instead of portrait  layout is also possible.

The issue is that smaller panels are 1.7m high, large panels are 2.3m high.

A 6m roof will not take 3 rows of 2.3m panels, but it will take 3 rows of 1.7m panels.

Other panels sizes are 1.9m or 2.1m high

As newer panels come to market, the older panels are phased out, so in a short period, the original design layout is obsolete, as the panels can no longer be sourced.

Any advice would be appreciated!

 

 

 

 

 

 

Edited July 21 by Solo

[Solo]

Some interesting commentary at the FB link below

https://www.facebook.com/share/p/6jWyJgp4C1L54hYz/?mibextid=oFDknk

 

Edited July 23 by Solo

[Kalahari Meerkat]

On 2024/07/21 at 9:55 PM, Solo said:

Any advice would be appreciated!

Not really much advice, other than you need enough space between the rows of panels, so someone can walk in between for potential maintenance, maybe a cable connection has picked up problem etc. and possible cleaning, here in the last 3 months, I've probably cleaned the panels every 2nd or 3d week... dry... dusty...

[Scorp007]

On 2024/07/21 at 9:55 PM, Solo said:

I am a trustee on a body corporate with a shared roof.

We are considering solar, and the 2 options are:

1. Body corporate owns the roof.

2. Owners share the roof.

It is likely that Opt 2 will be chosen, due to the complexity of obtaining agreement on Opt 1

My question is, how does one choose the panel size, as the roof space can be better utilised if we use 3 rows of 450W panels vs 2 rows of 550W panels?

Using landscape instead of portrait  layout is also possible.

The issue is that smaller panels are 1.7m high, large panels are 2.3m high.

A 6m roof will not take 3 rows of 2.3m panels, but it will take 3 rows of 1.7m panels.

Other panels sizes are 1.9m or 2.1m high

As newer panels come to market, the older panels are phased out, so in a short period, the original design layout is obsolete, as the panels can no longer be sourced.

Any advice would be appreciated!

 

 

 

 

 

 

2.1m high panels are still popular and at times a better fit for some smaller/older inverters. 

Not many apartments have the over 4.6m from the ridge tile to the gutter to fit 2 rows of 2.3m panels. 

[mmandcoroofing]

In short, I'd suggest you go with three rows of 450W panels. You'll maximize your energy production and have a smoother ride with maintenance and future-proofing.
https://www.mmandcoroofing.com/solar-panel-installation/

[PsyCLown]

On 2024/07/23 at 3:38 PM, mmandcoroofing said:

In short, I'd suggest you go with three rows of 450W panels. You'll maximize your energy production and have a smoother ride with maintenance and future-proofing.
https://www.mmandcoroofing.com/solar-panel-installation/

The concern is with regards to future proofing as the older, smaller panels may become obsolete.

Whether that will happen or when, who knows. However I feel it might start happening sooner than we think but I could be very wrong.

 

If we look at SIW: https://www.inverter-warehouse.co.za/collections/jinko-solar

They only have a single panel option in the 400W range, price per watt is also higher (R3.24) vs the price per watt on the 555W panel (R2.93)

 

So for now, it might make sense and be fine to limit it to the size of the older and smaller panels but in the future when they need to be replaced, if smaller sized panels cannot be sourced or perhaps end up most expensive due to them being hard to find it poses a challenge.

 

It makes sense to allocate a portion of the roof to the owner and let them decide how they want to best utilize it, although if you want to specify rows and how many panels I would rather opt to base it off the typical size of a 550W panel and provide panel size limitations (dimensions & not watts).

[Scorp007]

9 hours ago, PsyCLown said:

 

If we look at SIW: https://www.inverter-warehouse.co.za/collections/jinko-solar

They only have a single panel option in the 400W range, price per watt is also higher (R3.24) vs the price per watt on the 555W panel (R2.93)

If we look at this link you are not comparing like for like. The 440W panel is the NEO model with a 5 year longer warranty than the 555W. This will partially explain the price gap. Using the 575W NEO that is priced at R3.04

Using another web site you will find 4 sizes of 400+W and also 4 sizes of 500+W.

[PsyCLown]

On 2024/07/26 at 10:01 PM, Scorp007 said:

If we look at this link you are not comparing like for like. The 440W panel is the NEO model with a 5 year longer warranty than the 555W. This will partially explain the price gap. Using the 575W NEO that is priced at R3.04

Using another web site you will find 4 sizes of 400+W and also 4 sizes of 500+W.

I did not realise there was a difference, I thought it was the same. They're all from the Tiger line.

I see now that the 440W states 15 year warranty and the 555W and 575W state 12 year warranty, despite the 575W being listed as a Neo model as well.

 

Although as you said, even the 575W offers better rand per watt value.