Let's have a discussion around the pros and cons regarding the different solar panel mounting systems.

Is it worth going for more expensive systems like Renusol or Schletter vs a cheaper galvanized steel rail systems?

How much is corrosion an issue in the inland areas - Gauteng, etc.?

Any other general observations and tips?

 

Personally I would say go for the best your budget can absorb.

That said, my diy frame with parts from builders warehouse and some 100mm k2-multi rails and clamps does the trick just fine for me.
How long it will last here in Cape Town close to the sea is another matter altogether 🤪

Good question - first install I used Renusol. 2nd install i went cheaper option (can't remember name) - maybe a slightly more "cumbersome" install than the Renusol, but its a once off and when installed then its done...

 

As for longevity - good question...

The most expensive part of any home is undoubtedly the roof. Foundations, bricks, mortar and plaster are very cheap in comparison. Installing solar panels on a roof is typically an invasive procedure, because it involves permeating and /or altering the roofing material to achieve purchase for solar panel rails. The integrity of the roof needs to be maintained and preserved, because if it isn't, it can turn out to be very costly. 

Solar panels themselves are typically guaranteed for 25 years, and are exposed to the harshest possible conditions, and the mounting structure / rails are no exception. It makes sense to use mounting structure that has been designed by a team of engineers to carry the load whilst being exposed to the elements. It goes beyond just the design, also the selection of materials and fasteners. These are important because dissimilar metals fastened together speed up corrosion. Aluminium is stronger and weighs far less that galvanised iron.    

I guess that it all depends on how much one values the home's roof. I have seen some very poor installs in this regard, and have no doubt that panels will probably outlast the mounting structure. This is a problem because the panels are going to end up somewhere during a windstorm, creating a potential liability, and the roof is probably going to leak.

I am sure that there are some DIY installs that are very good, but personally, I would rather pay a small premium for engineered mounting structure upfront, and have peace of mind for the next 25 years.

Edited March 9, 20233 yr by YellowTapemeasure

5 hours ago, YellowTapemeasure said:

The most expensive part of any home is undoubtedly the roof. Foundations, bricks, mortar and plaster are very cheap in comparison. Installing solar panels on a roof is typically an invasive procedure, because it involves permeating and /or altering the roofing material to achieve purchase for solar panel rails. The integrity of the roof needs to be maintained and preserved, because if it isn't, it can turn out to be very costly. 

Solar panels themselves are typically guaranteed for 25 years, and are exposed to the harshest possible conditions, and the mounting structure / rails are no exception. It makes sense to use mounting structure that has been designed by a team of engineers to carry the load whilst being exposed to the elements. It goes beyond just the design, also the selection of materials and fasteners. These are important because dissimilar metals fastened together speed up corrosion. Aluminium is stronger and weighs far less that galvanised iron.    

I guess that it all depends on how much one values the home's roof. I have seen some very poor installs in this regard, and have no doubt that panels will probably outlast the mounting structure. This is a problem because the panels are going to end up somewhere during a windstorm, creating a potential liability, and the roof is probably going to leak.

I am sure that there are some DIY installs that are very good, but personally, I would rather pay a small premium for engineered mounting structure upfront, and have peace of mind for the next 25 years.

The life expectancy of galvanized iron rails is 50 years. That is double the panels life expectancy. Yes, they are slightly heavier but I don't think that will be an issue for the roof structure.

Galvanized steel brackets are also substantially cheaper. They don't have contact with other metals than the rails.

I'm not talking about incorrect mounting by not following the recommended guides and compromising the installation. How would the panels end up somewhere during a windstorm, creating a potential liability, by using galvanized iron, instead of aluminum rails. Would you be able to explain that?

Has anyone noticed significant corrosion issue in inland areas, using the cheaper mounting options?

 

26 minutes ago, PowerUser said:

The life expectancy of galvanized iron rails is 50 years.

Location location location. I live by the coast. Galvanised iron life expectancy is 10years max over here. Inland you could get the same 10y with no coating whatsoever. So be careful with blanket statements like that.

A important and often overlooked problem is galvanic corrosion. Dissimilar metals corrode each other when mixed. There is a galvanic scale for this reason.

Edited March 9, 20233 yr by root
additional info

3 hours ago, PowerUser said:

The life expectancy of galvanized iron rails is 50 years. That is double the panels life expectancy.

There are varying degrees of quality of galvanised iron, so that may be true for the galvanised iron that you are working with, some that I have seen is pretty shocking, already rusting at the warehouse, or in the shop at the China mall. It largely depends on the thickness of the zinc coating. Do you have a source to back your claim of 50 years' life expectancy up, and what point does this source declare that the galvanised iron has reached end of life? 

3 hours ago, PowerUser said:

Yes, they are slightly heavier but I don't think that will be an issue for the roof structure.

Not slightly heavier, it is significantly heavier -- more than double the weight. Whether it affects the roof or not would be dependent on the roof itself.

3 hours ago, PowerUser said:

I'm not talking about incorrect mounting by not following the recommended guides and compromising the installation.

This is exactly the problem: When working with a standard mounting structure system like that provided by Renusol or Schletter, it is difficult to deviate from their engineered solution, and the customer gets the engineering that they paid for, both in strength of design as well as selection of materials. With raw materials, everyone is an engineer and gets to do their own thing. Some will do a good job, some will over-engineer, and some will take short-cuts. To the customer, it's a lottery.

3 hours ago, PowerUser said:

How would the panels end up somewhere during a windstorm, creating a potential liability, by using galvanized iron, instead of aluminum rails. Would you be able to explain that?

Sure, it was pretty self-explanatory to me, but I will do my best. Aluminium is corrosion resistant, without any further treatment after it is spun, that means that it doesn’t rust. Iron / steel / alloys are prone to rust without treatment. Galvanised iron is treated with Zinc, the quality which varies from the process used and the thickness of the zinc. I have already mentioned that dissimilar metals fastened together speed up corrosion. This was further reinforced by @root who has given us the correct term for it: Galvanic corrosion. Galvanic corrosion occurs when an anode loses electrons to the cathode in the presence of an electrolyte, such as water. This process is sped up by contaminants in the atmosphere (acid rain) and exposure to the elements in general, as well as the fact that some panels' frames actually carry some electricity (hence they are earthed). The panels' edges, where they are fastened, are aluminium, so it makes sense to use aluminium clamps and anodised fasteners to avoid galvanic corrosion. If using another metal and not aluminium, there is a good chance that the fastener and other dissimilar metals such as clamps will corrode. Corrosion weakens the metal fastener/ clamp, and over a period of time the metal becomes fatigued. In other words, it is not very well fastened anymore. You can therefore imagine that because it is not well fastened, a strong wind could easily lift it and blow it about to wherever it eventually lands. 

Examples of galvanic corrosion:

 

Edited March 9, 20233 yr by YellowTapemeasure