Are semi-flexible Chinese Solar panels the same construction as rigid?

[dial-a-monkey]

The cynic in me wondered if the Semi-flexible (3%) Chinese solar panels are in fact the same construction as the rigid ones - just sold without the aluminium frame? and at a higher return to seller rate.

I don't have access to both to to compare and Google didn't return any results from any fellow conspiracy therorists.

Does anyone know if there is actually a real difference in the way the Cheapish Chinese panels are put together?

Thanks

 

[JumbleDuck]

The cynic in me wondered if the Semi-flexible (3%) Chinese solar panels are in fact the same construction as the rigid ones - just sold without the aluminium frame? and at a higher return to seller rate.

I don't have access to both to to compare and Google didn't return any results from any fellow conspiracy therorists.

Does anyone know if there is actually a real difference in the way the Cheapish Chinese panels are put together?

These "semi-flexible" ones are barely flexible at all. I bought one by mistake; it was listed as suitable for a "30^o bend" which was obviously, as it turned out, a mis-transcription of "3%", possibly by someone not used to the roman character set. It had a fairly heavy aluminium backing, about 3mm or so, with the cells bonded to it. It would be fine on a very slightly off-flat surface, but wasn't suitable for anything, like a coachroof, with an appreciable curve.

 

[Trundlebug]

Interesting, my semi flexible panel came with an aluminium backing only about 1mm thick, so was fine for mounting on the slightly convex roof.

A 3mm backing would give far better cooling though, so performance in bright / hot sunshine might be improved compared to mine, which has been disappointing. I've only seen max 6 amps out of a 150w panel - should be nearer 8 or 9 amps.

Maybe it depends where you get your panels from, probably not fair to assume all are the same.

 

[JumbleDuck]

A 3mm backing would give far better cooling though, so performance in bright / hot sunshine might be improved compared to mine, which has been disappointing. I've only seen max 6 amps out of a 150w panel - should be nearer 8 or 9 amps.

I gather that the manufacturers generally and optimistically calculate the power rating as "maximum open circuit voltage x maximum short circuit current", so 150W would be 20V-ish x 7.5A-ish and 6A wouldn't be bad. My 100W array (a posh word for two panels) has produced a maximum of 4A over the past two years, if the controller is to be believed.

 

[dial-a-monkey]

Thanks for the tip - I didn't see - until now - how often the ebay sellers use 3% and 30% flex interchangeably often in the same advert

I wonder if any of the panels are actually 30% The photos in the auctions are pretty deceptive.
Lends some support to my conspiracy theroy that they might just be rigid without the frame...Hmm

 

[TwoHooter]

There's a boat moored next to us with what must be a very flexible solar panel lying on top of his mansail bag and drooping down either side of it. Don't know where he got it and haven't seen him for months so can't ask, and don't know whether it works, but it definitely is flexible.

 

[V1701]

Unless they've radically changed the materials they're constructed from I'd avoid those panels. The flexible see through stuff (they had some fancy name for it) on top began delaminating on mine & I've seen the same on others...

 

[JumbleDuck]

Unless they've radically changed the materials they're constructed from I'd avoid those panels. The flexible see through stuff (they had some fancy name for it) on top began delaminating on mine & I've seen the same on others...

I bought two cheapish plastic laminated semi-flexible 50W panels a couple of years ago. They are bearing up just fine, and although I don't expect them to last desperately well, they only cost £250 for the pair, so I won't mind replacing them too much. I hope to get five years out of them. After that I expect to be able to buy better ones cheaper, which was another reason, or perhaps two other reasons, for not spending anything up to four times as much for tougher ones.

 

[VicS]

I gather that the manufacturers generally and optimistically calculate the power rating as "maximum open circuit voltage x maximum short circuit current", so 150W would be 20V-ish x 7.5A-ish and 6A wouldn't be bad. My 100W array (a posh word for two panels) has produced a maximum of 4A over the past two years, if the controller is to be believed.

The power rating quoted is Pmax. The full spec should also state the terminal volts at Pmax, V_Pmax, and also the current I_Pmax

V_Pmax is usuallysomewhere in the range 16 to 18 volts


If you multiply V_Pmax by I_Pmax you get Pmax