Solar Panels

In short yes, any shadow on the solar panel will effect the performance, solar panels by design require full sunlight to operate at peak performance.

Hi Ross,

The panel would be very ineffective if partially shaded. I did a test on mine using a Fluke multimeter in series with the load to see how much shading affects these panels. At full sun production if I moved my hand over a single cell slowly, current production would drop from 4.8 Amps to 2 Amps when 1 cell was a third shaded to under 1 Amp when 1 cell was three quarters shaded.

Try it to make your only conclusion however.

Cheers
David

Ross, we were experimenting with shade effects last Christmas. Was generating about 8-10amps with our 2/80w Sharp panels. Shaded 75-100mm strip across panels – I believe placing shade across width stops the ‘flow’ of electricity. Mainey might be able to be explain why – read about it once, can’t remember now why this happens. Flow dropped to about 0.9amps. We have polycrystalline panels and I believe other panels types not so affected by shade. Cheers

Depends on panel brand /make , Unisolar panels still work when part shaded although at reduced output.

My co-residents reckon shading usually does "choke" the whole output.
The shading is like squeezing a water hose - it cuts the lot.
It is not like eg: "10% in shade therefore (only) 10% less output".

But some panels are assembled differently - ie, paralleled strings (rare?) or "slither" construction.

Mono- or poly-crystaline won't matter.

When driving, it's trivial (use your alternator output instead... efficiency!!).
And when camped, I'd remove the shading racks or have the panels on removable else hinged racks for at least some improved alignment. (20° is about 10% less output.) Else add mirrors....


Triviality follows:
Sorry for any earlier complication. One minute of checking would have saved 10 of writing, and 100 of confusion. (I blame it on the night's earlier "expert" claiming certain solar power outputs. He was a bit stumped when I pointed out the max of about 1kW per square meter of solar energy at the earth's (equatorial) surface - their collector then needed 1,000 sq kms instead of 10... LOL!)

hi ross
the bottom line or the crukz of the matter is
yes
they are called solar panels because thats where they work to their best ability in the sun- it's elementary and simple !!!
if they were efficient in the shade i guest they 'd have called them shade panels
to put the solar panels under roof bars would be detrimental to it's output rate at all times because at no time no mater what the situation was regarding the sunlight could it be expected to produce full capacity partly shaded by roof bars
in other words your not giving it a fair go mate !would be like connecting 12volt lights to a 6volt battery???
imho it really defeats the purpose in other word to me why bother
imho its either roof bars
or
solar panels
not both
do a test yourself with a solar panel set it up in full sun and connect a multi meter to the output side then
shade it with the equivalent of bars or anything for that matter your leg /arm or body and you will quickly see how the output voltage drops off
this subject has been delt with before some time ago i recall the same question was asked
but i dont have the thread number
cheers
hope this of help