A solar panel that works with partial shade

[AlanandMayya]

Actually, correction, I say zero but you will still get the current provided by a shaded panel. But this will be very little!

 

[King Warwick]

Renogy 150 Watt CIGS Flexible Thin-film Solar Panel[/HEADING]
Others makes are available.
Cigs is the technically name

 

[Raul]

Then why does shading just the corner of one strip destroy the output?

Also, my panel:
View attachment 844031

I did answer to this in a previous post, you closed to Ignore it, and kept asking. I have seen brand new panels with bad diodes. These bypass diodes comes in various quality, big brands fit high quality Schottky,
Note, victron its not a big panel brand, they just do the sticker. If you look at temperature coeficient for example, and compare it to other panel brand names, specially to top 5 panel producers in the world, you will realise that victron panels are really pants compared to a LG, SunPower, Jinko, JA Solar, Trina etc.

Like i said, if one shaded cell takes the whole panel down, there is no diodes or bad diodes. That panel will develop brown spots if exposed to regular shading.

 

[JoCo]

As all of us do not have the Tech knowledge of contributors. Will someone post a TECH SHEET of a solar panel and highlight the most important items on the sheet , and the parameters IE volts range . Or if there is a reliable trust worthy internet site that sets these out, post that as a reference.

 

[Don Campbell]

Quick google

This is not the case with bifacial solar panels- instead, these types of panels have solar cells on both sides. This enables the panels to absorb light from the back and the front. Practically speaking, this means that a bifacial solar panel can absorb light that is reflected off the ground or another material.6 Nov 2023

How could that possibly work since there is no reflectecd light from the underside of a panel on the top of a motorhome or am I missing something?

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[Raul]

How could that possibly work since there is no reflectecd light from the underside of a panel on the top of a motorhome or am I missing something?

Who said you will benefit from bifacial panels on a motorhome roof?
Bifacial panels are for pergolas, car ports, ground mount arrays, atrium roofs, etc. That way they will get some reflected light on the rear cells and boost production.

 

[AlanandMayya]

If you have panels on a flat roof (like my garage) and dont want to adjust them, they will be set at about 35 degrees optimally in UK, facing due South. In Summer, the sun is in the North at the start and end of the day, so, behind your panels. Bifacial panels just have a transparent backing so that sunlight impacts the cells from the rear also. Also, you can hang panels like sails, facing East /West; then the bifacial action doubles your generation. You see these in the Alps, at ski resorts. The advantage here is that max power is at the start /end of the day, instead of at midday with South facing panels - useful if you have no battery, or a small one. As battery prices fall these installations have become less popular.

 

[jongood]

Renogy 150 Watt CIGS Flexible Thin-film Solar Panel[/HEADING]
Others makes are available.
Cigs is the technically name

I have CIGS panels on my House and amongst the brilliant things is they re not made in bl**dy China.

Index Page - BiPVco -The Building Integrated Photovoltaic Company

Sustainable design, powered by BIPVco

bipvco.com

The other great things are they are supposed to be better at low light, they re thin film properly flexible and almost invisible on the house roof.

edit, they also make them for MH's but they are long and thin

Downside is that the house needs moving a bit further south

 

[jongood]

Here's a pic, the panels are the dark bits

 

[AlanandMayya]

Looks very neat. I guess that is the future of PV panels and in 20 years time today's thick glass panels with ali profile frames will visually remind us of those 1970's portable phones, the size of a house brick. But you do pay quite a premium for thin flexible panels today.

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[autorouter]

Yes, thanks, I forgot that. But even so, at low temp (20C) and near Imax I think Schottkies still drop 500mV or so. I looked at some data sheets when I was considering designing a B to B charger to charge a 50V battery from 12V. (Too hard for me; gave up and did it a different way). I remember in my youth Germanium was the semiconductor of choice and only dropped about 300mV. I suppose there are lots of good reasons it was replaced by Silicon.

Standard silicon junction diodes, with a PN junction, do have a forward voltage drop of 700mV or so. They usually have very high reverse voltage breakdown. Unless it is deliberately reduced, as in zener diodes.

A schottky diode is a metal electrode on a silicon base, no PN junction. Its forward voltage drop is much lower, around 200mV to 400mV. However its reverse voltage is not so good. If it's used in a situation where the reverse voltage doesn't matter much, then its low forward voltage drop can come in very useful, as in solar panels.

Germanium is still used in specialist applications like infrared detectors and high energy particle detectors, but silicon is so much cheaper and easier to work with.

 

[AlanandMayya]

Thanks! The things you learn by living in a van, eh?

 

[cyberyacht]

I had a quick look into CIGS panels. As Chief Brodie almost said "You're gonna need a bigger roof". The panels are about 50% bigger than conventional panels of the same output.

 

[NASHMAN600]

Shade effects all panels, as discussed above. The normal Commercial size panels say approx 400 watts use 3 diodes , last year my friend bought some Hyundai panels that were of the shingled design. We tested my Ja solar panel 385watt Vs his shingled 390 panel.Shading different parts of the panel and seeing the power output.
The shingled panel outperformed my conventional Ja panel under all partial shade tests.Attached is the difference in design.
Obviously this is relevant to 400 size current panels, not smaller motorhome size 100-120 watt.
I think any smaller size panel will suffer badly with any shading.
My answer is to have a separate wandering panel a victron 140watt, on a 12 metre wire attached to its own Solar controller.
I have 2 MHD 120 panels on the roof .
All I can say is my victron 140 panels outperforms my two roof panels 85 % of the time as I can angle and tilt it for max performance.Something that can't be done for the roof panels .They need the sun high at midday to max out..
I have the wandering Panel because of the shade when staying in the New Forest off grid or parked near a treeline..