Keeping it simple, I want a "shed light" that operates during the day.
They seem to consist of a 12v led spotlight and a 5 watt solar panel
but most I've seen for sale don't have detailed specs. These would be
fine except I don't want to store the power
Sounds like your shed is as dingy inside as mine!
Others have suggested a skylight, but that assumes
that one skylight will give enough light, where you
need it. The LED approach allows the possibility that
you can move it around to different areas as needed.
The advantage of having the battery is not just at night.
Since the sun comes and goes behind clouds, the LED
brightness would fluctuate without a battery reservoir.
LED brightness is controlled by the current through them,
while the voltage across the LED is nearly constant. Without
some sort of current limiter, a tiny increase in voltage could
cause a whopping big increase in current and blow the LED.
So normally the LED is driven through a resistor or a special
current supply... almost *never* straight from a voltage source,
unless it is something with an intrinsic current limit. Your
solar cells may or may not fall into that category. My guess
is that you can probably come up with such a system, but
you might have to test a bunch of cells and LEDs first.
So, it's probably simplest to use the resistor or current
limiter right from the start. Personally, it seems simpler
(and probably no more expensive when all is said and
done) to use the ready-made battery system. They've
probably optimized it and gotten the prices down via
mass production in offshore plants... you will have to
pay more for the parts, even if you work for free.
Just a thought...
Bob Masta
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
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