Not following your description, Jon. Do you have a pic of what you did with the
PC board?
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
"Anyone who believes exponential growth can go on forever in a finite world is
either a madman or an economist."
-Kenneth Boulding, economist
“How unfortunate that the Earth’s first intelligent social animal is a tribal
carnivore”
-E.O. Wilson, sociobiologist
From: Jon Elson <[email protected]>
To: Enhanced Machine Controller (EMC) <[email protected]>
Sent: Saturday, November 8, 2014 3:33 PM
Subject: Re: [Emc-users] Off Topic: Shop Lighting
On 11/08/2014 11:29 AM, Dave Cole wrote:
>>> I wonder how long it takes to pay back the $75
> difference at 9 watts?
>
> 9 watts x 2000 hrs per year = 18KWHR/yr @ $0.10 per KWHR that would
> be $1.80 per year so a payback of $75/$1.8 = $41.6 years
>
>
I made up my own LED retrofits, because I couldn't find
anything that looked
like it would work well. I bought Cree 1W LEDs, and put a
string of 20 of
them on strips of PC board material with little grooves
cutting the
copper path. Each LED has 2 square inches of copper as a
heat sink.
I used commercial LED lighting regulators, which were pretty
expensive.
I have these in the kitchen, where they are on a LOT of the day.
One strip of 20 LEDs is brighter than 2 32 W 48" fluorescents.
Not only looks brighter, but my photometer also says they are
brighter. I have them suspended inside the drop ceiling dual
fluorescent fixtures with 2 x 4' plastic diffusers that were
there before.
I measured the power draw of the old magnetic ballast, it
was 103 W
with a real power meter. The new system reads 21 W.
I guesstimate payback in about 3 years.
I first did a 10 W unit with a power supply I made myself,
it has been running
about 18 months so far, and is still working really well,
too. I think if you
use good LEDs at reasonable current levels, the dimming over
time will
be very slow. Cree has lifetime charts that show several
hundred K hours
before significant loss of brightness. I did make sure the
LEDs run pretty
cool, much cooler than a lot of the stuff sold in stores.
Jon
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