Cheapest Simi-Flex Solar Panels

Ian_Rob said:
As I understand it, 8.9v panels like the 50W (1030 x 280 x 3mm) supplied by Photonics Universe require a so called buck-boost controller if used singularly, as the output voltage of one panel on its own is below the charging voltage of a 12v battery. As I want two 50w panels , I am told that a buck-boost controller isn't required but what are the implications if one of the panels is shaded?
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Fit 2 panels and wire them in series. Job done
 
So simply wiring them in series overcomes all shading issues and will allow them to work with controllers that aren't buck boost? Would there be any advantages in choosing a MPPT controller with these lower voltage panels?
 
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Ian_Rob said:
So simply wiring them in series overcomes all shading issues and will allow them to work with controllers that aren't buck boost? Would there be any advantages in choosing a MPPT controller with these lower voltage panels?
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Not an expert but I thought two panels should be in parallel to minimise shading issues ?
Interesting that the square shaped Photonics Universe 50W panels have much higher voltage than the 50W long narrow panels
https://www.photonicuniverse.com/en...lls-for-motorhome-caravan-camper-rv-boat.html

These certainly work fine in parallel on our sprayhood, where one is often shaded, into MPPT controller
 
..... or would the total output have to be controlled to a suitable charging level - by which time it all becomes a bit inefficient?
 
Quick update, I've just received a new 100 watt panel from Banggood, the closest to square I could find, roughly 800x750. Just tested it, panel horizontal, the day is bright but not what I'd call sunny, back of lunchtime so the sun is probably as high as it's going to get. 18.5 volts open circuit, putting 3.5 Amps into my 12 volt battery. Not bad for the North of Scotland. Just over £100.
 
Graham_Wright said:
Not really relevant to marine use but our camper van has a rigid 100 W panel (£67 on ebay) pivoted at one long edge. It has a tracker that seeks the brightest angle and raises/lowers the panel for optimum. I park the van east/west.

Although the panel is restricted to 90° maximum (i.e. it favours either the east or the west) it has been impressive.

Fascinating to watch/listen to.

Has anyone used a flexi panel for a bimini cover?
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I described Lensun semi-flexible panel in this thread and included a link to a video showing how it was fixed to the awning.
http://www.ybw.com/forums/showthrea...-solar-panel&p=5788796&highlight=#post5788796

I did eventually find a hair line crack in my original failed panel. I thought it had failed at the link between cells but eventually found it running across a cell. Top marks to Lensun for prompt replacement even though I didn't buy the original panel from them directly.

I'm still pretty happy with the panel on the awning as it is light and easy to remove when the wind gets up and we need to fold the awning away. Performance hasn't been as good as the rigid panels and would only equate to a 60-70W panel using my 145W rigid panels as a benchmark.

I think that output drops off more rapidly than the rigid panels as the sun moves from directly overhead. This lack of efficiency could well be due to the cheap regulator I'm using. The rigid panels go via a Marlec HRDi PMW unit and perform very well. The flexible panel output is lower than expected but I can get the specified short circuit current by removing the regulator. Shading the rigid panels doesn't boost the output from the Lensun panel and both regulators are set to reach a maximum of 14.8V.

I've only had one season so far from this panel and am hopeful that an MPPT regulator will make a big difference to output. I'm also considering adding a light aluminium support frame to the panel so that it reaches both support frames. This will remove a slight sag from the awning and minimise flexing as it bounces slightly in strong winds.
 
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I'm surprised that any panels give as little as 8.9v. The first panel I had was only 10w but still produced 17v open circuit. I ignored shading issues and still have got useful input (although not optimum) without continual repositioning.
I've never heard of buck boosting but would suggest getting panels with a higher output voltage in future.
Ian_Rob said:
As I understand it, 8.9v panels like the 50W (1030 x 280 x 3mm) supplied by Photonics Universe require a so called buck-boost controller if used singularly, as the output voltage of one panel on its own is below the charging voltage of a 12v battery. As I want two 50w panels , I am told that a buck-boost controller isn't required but what are the implications if one of the panels is shaded?
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Quite a few of the long, narrow, semi-flex panels have outputs that are around 9v. I don't think that is necessarily a huge problem as being long and thin can be very useful when positioning but it does need bearing in mind when choosing them and the controller(s) that will be needed to go with them.
 
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I've had a look at the ones on eBay and haven't found any less than 17v output. Any less would make them unsuitable for charging a 12v battery, which is what they're mostly used for.
 
ghostlymoron said:
I've had a look at the ones on eBay and haven't found any less than 17v output. Any less would make them unsuitable for charging a 12v battery, which is what they're mostly used for.
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http://www.ebay.co.uk/itm/50W-flexi...484521?hash=item1a06198169:g:0HQAAOSwT5tWJ7VI. They become suitable for charging a 12v battery by using a buck-boost controller.

Nor is the issue isn't confined to cheap panels. A friend of mine needed a narrow panel and on the advice of Barden, installed a 50W a Solbian SP50 [ 1109 x 292 x 2mm] last season that used Genisun controller to raise the voltage to the required charging voltage.

SEE http://barden-uk.com/product/solbian-sp-50l/
 
I've got a narrow (30cm) 20w panel to fit between my main hatch and handrail. It's output is about 17v on a good day (such as today?) and charges my battery via a simple PWM controller. I think it's a Lensum.
 
ghostlymoron said:
I've got a narrow (30cm) 20w panel to fit between my main hatch and handrail. It's output is about 17v on a good day (such as today��) and charges my battery via a simple PWM controller. I think it's a Lensum.
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There is a massive difference in the output of your system and the one quoted in the post above. Take a look at the top ocean racing boats and they pretty much all use Solbian panels so the idea that low voltage with boost isn't suitable is sadly wrong.

Your PWM controller is not getting the best out of your system but if it's enough for your needs then lovely. I assume you use it to trickle charge when away from the boat.
 
I agree that my installation is in a different league to an ocean racer but so is my power requirement. As for trickle charging when I'm away from the boat - it's a permanent installation and charges whether I'm on the boat or not. I am aware that my controller is not the most efficient type, but at ten quid is certainly cost effective and it doesn't make economic sense to replace with a MPPT type on such a small panel, I could double my panel area for less.
Buck Turgidson said:
There is a massive difference in the output of your system and the one quoted in the post above. Take a look at the top ocean racing boats and they pretty much all use Solbian panels so the idea that low voltage with boost isn't suitable is sadly wrong.

Your PWM controller is not getting the best out of your system but if it's enough for your needs then lovely. I assume you use it to trickle charge when away from the boat.
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Dougal said:
There seems to be a HUUUUGE price range/difference between some of these panels.
I'm looking for a small (80-100watt) panel to lay on a slightly curved coach roof.
Any recommendations for suppliers of these at sensible prices?
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I use a 100watt semi flexible type off Ebay for about £130. Its attached to the pilot house roof with spray foam (this has held it solidly for over 12months and does make removal possible, unlike using PU adhesive.)

A Victron mppt controller replaced the cheap pwm type.

It replaced a 20watt panel which proved inadequate during a typical Scottish winter.

No problems so far, just fully charged batteries.
 
cmedsailor said:
Thanks.
May I ask, do you ever see around 5 amp coming in during a sunny day?
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Not yet but that's because my batteries are always charged and I've not been on board overnight to drain them. (The engine is usually running when using the electronics so not much of a drain during the day.)

(The reason for going from 20 to 100watt is because of the limited sunlight in Scotland, rather than needing the full output.)
 
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