Replacing solar panels

Brianvicki · Veteran Member

Replacing solar panels

Burt65 · Veteran Member

Brianvicki wrote:
We have 2 x 120w solarking panels on our poptop, seems like one is now faulty, and of course I that exact size one is not available now.
so it looks like I will need to replace both panels, we only use about 25 amps overnight from our 100 amp lithium, so anything from 240 to 300 watts is ample for us (were inWA, so lots of sun generally), what panels do people recommend, Im thinking of these new Renogy panels, but not sure if I really need them at the cost and the advantages I might get.
https://au.renogy.com/renogy-200w-shadowflux-anti-shading-n-type-solar-panel/?Rng_ads=56cd787036485d32&kw=&ad=&gr=&ca=22150515033&pl=ga&gclid=CjwKCAjwvuLDBhAOEiwAPtF0Vqmf1MMw2ddW9HY4XcORFw_lPtSt-QBC2ST-6fFMH9M85PSIC6aABhoCK-cQAvD_BwE&r_u_id=1912567345&gad_source=1&gad_campaignid=22150520040&gbraid=0AAAAADJwR9IRxGuMAR0C7LcF6-3ZzRQJO

also, is there any secrets to removing the current panels? Ive attached pictures to show the silastic etc..

I have two Renogy on my roof 100W each for the engine battery, and in all honesty the best wattage I got since day one was of 137 watts combined.. They are installed same way as all the other panels (Sunpower) I got, but the other panels have always given me a much more realistic wattage, as in close to the wattage rating of the panels.. You do as you wish with this info..

To remove the corner from the roof, there is only one way and it is mechanical. First remove the panel from the plastic mounting corner, then gently start to cut the silastic bit by bit with a good 25mm sharp blade. If cleaned properly, you can easily re-use those plastic mount..

Most silastic are removable only by mechanical mean. There are no chemical or trick of the trade available..

EDIT:

Also remember that the surface where the silastic will go and the thickness of the silastic are very important.. For instance Sikaflex, recommend a minimum thickness of 5-10mm of beed and not to be press down all the way, so to retain the elasticity required in such installations. They also recommend priming the ABS plastic mount with Primer Sika 215 to assure maximum adhesion to the plastic and Primer Sika 206 G+P for the actual roof..

Good luck..

-- Edited by Burt65 on Friday 18th of July 2025 12:26:24 PM

Are We Lost · Guru

A little surprising to see Burt's comment not being happy with Renogy. The brand has a reputation for quality (as does Sunpower), although I have no first hand experience of either to relate. Whatever you choose, check the dimensions and claimed watts. Particularly on ebay some sellers are quoting outrageous figures.

I note the linked panel quotes 25% efficiency but in the specs it refers to module efficiency of 20.7%. The difference is the first one relates to each cell in lab conditions, while module efficiency is the whole panel including frame and space between cells. 20.7% is good, but not leading edge. It seems to be priced about right for that.

I have a Jaycar 120 watt panel purchased 2012 and still performing fine. Then in 2018 I bought an ebay one quoted at 200 watts. I knew by its size it was overrated and I calculated 150 watts. When mounted, it did produce a bit more than the 120 watt Jaycar. But after a couple of years I could see fine cracks in the silicone. Now it has dropped to below the 120 watt Jaycar. Quality matters.

As for the mounts, I am not a fan of the plastic mounts. I came close to losing a panel where the mounts had degraded and cracked due to UV exposure in less than 2 years. Also, when you remove them, look underneath at the small surface area for adhesion. I replaced them with galvanised brackets.

Bunnings galvanised brackets

I actually used smaller ones but if doing it again would mount the panel a little higher so leaves etc don't collect underneath as much and can be cleaned more easily. Another mistake was to bolt the panels to the brackets instead of screws. I can't remove them without the tedious job of removing the brackets as well.

Burt65 · Veteran Member

I wasn't actually surprise by the lower wattage supplied by the Renogy considering their cost.. They are cheap panel and they seem to perform accordingly.. From 200watts of solar panel, I would say a good result would have been more around the 170watts or 85% of their capacity.. I never bought any other Renogy panel, so I can't say if this is the norm or an isolated case..

Also, regarding the Plastic mounts, mine have been going strong for 10 years now, but I agree with you. If I had to do it again, I would use the standard roof installation system. Much stronger and cheaper..

Edit:

at Brianvicki

After a quick search, I found those panel for sale at $305 per panel instead of $319.99 from the link you posted... Several sites have them for the $305 price.. HERE

-- Edited by Burt65 on Friday 18th of July 2025 02:19:22 PM

Are We Lost · Guru

Burt65 wrote:
..... regarding the Plastic mounts, mine have been going strong for 10 years now, but I agree with you. If I had to do it again, I would use the standard roof installation system. Much stronger and cheaper..

Perhaps 10 years ago they were quality. Here is one of the cracked and broken brackets from mine. Note the small surface area for adhesion and how much of that was broken away. I had used screws as well, but not much benefit if the mounting flange breaks away. I did break a bit more away when releasing from the adhesive but they were well and truly past it. The cracks are enough evidence of that.

-- Edited by Are We Lost on Friday 18th of July 2025 02:41:26 PM

Burt65 · Veteran Member

Are We Lost wrote:
Burt65 wrote:
..... regarding the Plastic mounts, mine have been going strong for 10 years now, but I agree with you. If I had to do it again, I would use the standard roof installation system. Much stronger and cheaper..
Perhaps 10 years ago they were quality. Here is one of the cracked and broken brackets from mine. Note the small surface area for adhesion and how much of that was broken away. I had used screws as well, but not much benefit if the mounting flange breaks away. I did break a bit more away when releasing from the adhesive but they were well and truly past it. The cracks are enough evidence of that.

-- Edited by Are We Lost on Friday 18th of July 2025 02:41:26 PM

Regarding the "small" surface for adhesion.. That's a lot bigger than what we use for the windows in coaches.. The biggest problem I can see there is that the plastic was not primed and therefore the silastic never actually had the chance to adhere to the plastic. You can still see the shining of the light on one side and the dirt from the weather and water on the other side of the plastic. Not sure what created those crack, but I wouldn't blame the sun for that... To my knowledge, ABS plastic does pretty well under the sun...

Like I said, I wouldn't use the ABS pieces (either the long one or the corners) anymore if I had to do the job again, but it is only for the cost involved in installing them properly, not for the reason you mentioned..

Are We Lost · Guru

Adhesion is a separate issue. As per my previous comment I broke the bracket a little more when releasing from the adhesive. It was still mostly adhered. But I know there are better choices for adhesive. My replacement brackets are affixed with Sikaflex 11FC. I think the previous one may have been 291.

There are no shiny parts on the surfaces for adhesion. Not sure what you think you are seeing. You can see the cracks have been there some time and these were only 2+ years old.

Anyway, adhesion was not the issue. I had one bracket where the flange was still stuck down, but had cracked and separated from the rest of the mount. Once the flange separates there is only about 10% of the surface area left for holding it in place.

Anyway, I have had my say and hope others using platic mounts check them for cracks. I will leave it with this image of all 4 brackets showing the flanges broken off. The one in the previous photo is the top left .... the mount with the most surface area remaining. I think the one on the bottom right was floating free, entirely disconnected with broken flanges, or part thereof still adhered to the roof.

-- Edited by Are We Lost on Friday 18th of July 2025 05:01:13 PM

Burt65 · Veteran Member

From the dictionary:

shine /shn/

intransitive verb

To emit light.
To reflect light; glint or glisten.
To distinguish oneself in an activity or a field; excel.

Can you see it?

I can...

Are We Lost · Guru

That is not a contact area. It is about 10mm higher than the adhesive surface.

Burt65 · Veteran Member

Sorry. I just re-read your reply.. Ok, you probably didn't use the shiny part for gluing but I did, just one big blob of Sikaflex. I just realised now what you meant for surface adhesion..

So you are right, there is no reflection where you meant. But there are no rules in how to glue those pieces down.. If you want to use only the edges, that's up to you..