Help - 240W from a 670mmx780mm (26.3inx30.7in) flexible panel?!?

[yourmate]

Hi guys, was lurking around for some time but as I now about to start my own build I have some doubts and questions...

The installation will go on the top of a 2016 VW Crafter LWB (basically, same as a Sprinter) which will have 2+1 air vents and a 4G aerial on the roof so right spacing is crucially important. Budget is medium, but what I've gathered from Will's videos with solar panels cheap does not necessarily mean shit...

The top of the van is 4,100mm x 1,400mm (161.4 x 55.1) so initially, I decided to go with 6 pieces of 150W panels: 2 next to each other and 3 rows. They are 920mm x 665mm (36.2 x 26.1) for roughly £110 (UK) which would give me 900W max roughly on a 3,000mm x 1,400mm (118,1 x 55.1) combined surface which I would say decent enough.

Now, commited to buy I had a final look around and I have find said solar panel in the title coming from China. I am a bit sceptical, sent a message to the seller to see the data sheet on the back of the panel, but I've thought I'd ask you guys as well.

So the specs are:
240W (says 18V, but no amps, no Voc, nothing)
670mm x 780mm (26.3in x 30.7in)
flexible panels
£90 so roughly 10% cheaper

This would give me 960W in a 2x2 config or a whopping 1.4kW on pretty much the same surface (actually, a bit less) as the 150W panels.

Is it a big fat lie about the wattage or did somebody actually see a panel like this IRL?!?


pm. There is a 340W version (see attachment) but that's currently out of stock...

 

[svetz]

I'm leary of flexible panels as they have very poor track records, some say they don't even get 5 years from them Then there's this:

Flexible Panels hit Prime Time?​

 

[gnubie]

The ratings are false. The watts / square metre is 2.25 times that of a reputable brand such as LG, and even higher when compared to a typical run of the mill panel.

*edit to de-americanise*

 

[yourmate]

The ratings are false. The watts / square metre is 2.25 times that of a reputable brand such as LG, and even higher when compared to a typical run of the mill panel.

*edit to de-americanise*

Exactly my thinking.
So what is the play here? Will the back of the panel sticker lie?
Obviously, in very Great Britain I cannot check the voltage on the panels during the summer. let alone in October...

 

[yourmate]

I'm leary of flexible panels as they have very poor track records, some say they don't even get 5 years from them Then there's this:

Flexible Panels hit Prime Time?​

Doesn't really matter as I don't want glass panels on a van doing 80 on the motorway

 

[gnubie]

Exactly my thinking.
So what is the play here? Will the back of the panel sticker lie?
Obviously, in very Great Britain I cannot check the voltage on the panels during the summer. let alone in October...

The sticker will say what ever the seller, or the entity the seller bought them from, paid to have printed on it. If enough panels were bought the label printing may have even been thrown in for free. That's China for you.

 

[fat_old_sun]

Hi guys, was lurking around for some time but as I now about to start my own build I have some doubts and questions...

The installation will go on the top of a 2016 VW Crafter LWB (basically, same as a Sprinter) which will have 2+1 air vents and a 4G aerial on the roof so right spacing is crucially important. Budget is medium, but what I've gathered from Will's videos with solar panels cheap does not necessarily mean shit...

The top of the van is 4,100mm x 1,400mm (161.4 x 55.1) so initially, I decided to go with 6 pieces of 150W panels: 2 next to each other and 3 rows. They are 920mm x 665mm (36.2 x 26.1) for roughly £110 (UK) which would give me 900W max roughly on a 3,000mm x 1,400mm (118,1 x 55.1) combined surface which I would say decent enough.

Now, commited to buy I had a final look around and I have find said solar panel in the title coming from China. I am a bit sceptical, sent a message to the seller to see the data sheet on the back of the panel, but I've thought I'd ask you guys as well.

So the specs are:
240W (says 18V, but no amps, no Voc, nothing)
670mm x 780mm (26.3in x 30.7in)
flexible panels
£90 so roughly 10% cheaper

This would give me 960W in a 2x2 config or a whopping 1.4kW on pretty much the same surface (actually, a bit less) as the 150W panels.

Is it a big fat lie about the wattage or did somebody actually see a panel like this IRL?!?


pm. There is a 340W version (see attachment) but that's currently out of stock...

670mm x 780mm works out to 0.52 m2. A 100% efficient a panel would deliver 520 Watts. There's no way a silicon solar panel can deliver 240 Watts

 

[Forbisher]

670mm x 780mm works out to 0.52 m2. A 100% efficient a panel would deliver 520 Watts. There's no way a silicon solar panel can deliver 240 Watts

At a quick glance that's a 100 watt panel.
This kind of fake panel probably only has Voc on the label with no amps listed.

 

[yourmate]

At a quick glance that's a 100 watt panel.
This kind of fake panel probably only has Voc on the label with no amps listed.

Many thanks for the input (BTW I am not getting emails about the replies, strange)
TBH, for that size, even 100W was fine as I would be able to fit 8 of them and still have place to mount my fans and stuff...

 

[yourmate]

670mm x 780mm works out to 0.52 m2. A 100% efficient a panel would deliver 520 Watts. There's no way a silicon solar panel can deliver 240 Watts

Is that a rule of thumb? So as these are usually 25% efficient half a m2 would mean 125W?

 

[Craig]

One more thing to think about is no matter how efficient any panel is once you lay it flat on a roof you will probably lose another 50 percent especially in winter.

 

[Forbisher]

Is that a rule of thumb? So as these are usually 25% efficient half a m2 would mean 125W?

20% so that's a 100 watt panel.

 

[yourmate]

One more thing to think about is no matter how efficient any panel is once you lay it flat on a roof you will probably lose another 50 percent especially in winter.

Yeah, but that's a given, so I don't worry about that.