What Solar Panels to Buy

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WarrenK
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What Solar Panels to Buy

Post by WarrenK »

I pulled out our caravan from its 3 year hibernation and went to give it a well deserved wash. While up washing the roof it could plainly be seen the solar panels were not in a very good condition. These are a 45w light weight panel. The shine had gone from the plastic coating on them with a few of them also having the coating above the cell breaking away. I don't know what output I have(if any) as the weather in Qld presently is cloud and rain with no sunshine. I think I will replace them all.
I would like reasonably light weight panels that will with stand UV better than the ones I have. I have 600 watts made up of 13 -45watt panels. This time I think I would go for 100w panels, although the idea with the small panels is, if any were shaded I would only loose 45w per shaded panel.
As I have not been looking at panels and the outputs available for the last 8 years I would like to hear from anyone that has any experience with the latest panels. Thanks.
This is what they looked like and the layout of the panels when they were first installed.
IGO Solar.jpg
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BruceS
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Re: What Solar Panels to Buy

Post by BruceS »

Give them a good buff up & check them first as it's surprising sometimes just how little they do lose.
Unfortunately you have that much 'furniture' all over the top that you are restricted in type/shape of panels to use.
good luck.
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Re: What Solar Panels to Buy

Post by RobertNotBob »

Bruce do you mean just a good scrub and wash or use a polish on them?
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Re: What Solar Panels to Buy

Post by BruceS »

Couple of times I've just used ordinary fine cut'n'polish for doing a car & in between I just use polish'n'wax. After the polish the dirt, dust & bird poop washes of so much easier with just water through a gun on the end of a hose.
In the original persons position I'm not real sure because a couple of things threw me out. They might be those 'plastic' roll up portable things?
"QUOTE:The shine had gone from the plastic coating on them with a few of them ENDQUOTE.
I've never seen panels with plastic coating?
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Re: What Solar Panels to Buy

Post by RobertNotBob »

Flexable panels the one on my ute peeled off and I replaced end last year.
WarrenK
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Re: What Solar Panels to Buy

Post by WarrenK »

The two attached photos are what the panels looked like when they were installed and what they look like now. The picture of the now one has the plastic peeling and the wire running around the cell broken. There are 4 panels that look like it. The surface of them is like sandpaper, but strangely enough happened when they had been undercover. These cells are about 3mm thick and although lightweight not flexible.
Solar1.jpg

New

Solar2.jpg
Now
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Re: What Solar Panels to Buy

Post by supersparky »

Warren, I would wait for a couple of days and see what T1 has to say, when he gets back on the forum. I know he uses the square 60w panels on a lot of his jobs now.
From my experience, the output of some of the older panels decreases remarkably, over time.
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Re: What Solar Panels to Buy

Post by nut17 »

Once the surface layers start breaking up those panels are beyond repair and will need replacing. I went down that track back in 2015 with semi flexible panels that failed inside twelve months and would never fit them again.
This link does cover my story. https://www.nzmotorhome.co.nz/forum/vie ... re#p101750
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Re: What Solar Panels to Buy

Post by T1 Terry »

They look like the Q Solar semi flexible panels. Most of these started to roll up and the surface cracked open when attempting the flatten them out again.
We use the 60w panels now, rigid frame and glass top so they don't suffer the roll p problem. Flat mounted on the roof they really only produce 50w on average, but the smaller size makes them great for fitting in spots that would normally suffer shade for most of the day.
These 60w panels work best in series strings of 4 or more panels, depends on the MPPT controller you use but worth spending the extra money for a controller that will handle more than 100v open circuit. 4 x these 60w panels adds up to 88v open circuit, so 5 panels in series is 110v and the 100v MPPT will just shut down if they see over their 100v limit.
If you build a system with multiple strings of series linked panels and feed them into a single MPPT controller, you will need to add a diode on the positive output of each series string before it joins together with the other cables from the rest of the series strings. This will stop the output from the higher voltage output strings from flowing into any shaded panel strings and turn them into heaters and wrecking the panels.

T1 Terry
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WarrenK
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Re: What Solar Panels to Buy

Post by WarrenK »

Thanks Terry for the information. Although I was trying to avoid the extra weight of glass(44 kg spread over the frame I have attached to my roof should be OK) the rigid frame glass would the ideal way to go. What brand panels would you reccomend? Currently I have a 20a Dingo solar with solid state relays, what would the best solar controller to replace this(I will have twelve 60watt panels)/

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