"GregS" wrote in message
...
In article , Eeyore
wrote:


GregS wrote:

Eeyore wrote:
GregS wrote:
Eeyore wrote:
Arfa Daily wrote:

With a bit of work, I'm sure that they [LEDs] will
also get to the point where they can replace a standard filament
bulb,
in
the same sized package, unlike a CFL which has to accommodate the
ballast.

To run LEDs efficiently from 240V AC will also require some active
electronics.
I see no-one ever factors in the power losses that'll be associated
with
that.

When you use up the watts, you get heat. The lamp has to efficiently
get
rid of it. May even need a fan.

Quite possibly so. How many watts does the fan need ?

I have one here that's 40mm sq. It still uses 1W.


I'm actually using a CPU sink/fan combo, but the LED's are epoxied to a
copper
plate. I even have diamond dust as a buffer/insulator. To close space
the
LED's
I needed the best thermal transfer. Did I forget to mention the Peltier
device.
I am also using unmounted LED's.


In my experimental 45 watt, 9- 5 watt Luxeon array, I use copper,
aluminum,
and a fan. DC drive is nice.

The normal home doesn't have DC. What do you use for current limiting
and
how
much power does that dissipate ?

Nothing is compact. I use a large variable supply.

And the efficiency of that is ?


There is 45 watts going to the LED's.
About 20 amps. 3 series sets of LED's. You cannot look at the
light.
The device was intended to be flashed in the final form. peaking at
about 60
watts.

So how do you control the LED current ? I imagine you may have current
sharing
issues with parallel chains
too.

What's the AC input watts ?

Not sure, but I am not concerned with efficiency. I am concerned with heat
dissapation.
With same batches I have. the individual specs are very close together, so
load distribution is no problem at all. I use a variable voltage/current
supply. I
just have to watch to easily move the controls. This is just a test hookup
for now. I am using blue and green colors, they will be strobed to get
effects.

A few months ago I bought a batch of cool white 3 watters. I intended to
put
some around the house and control them with X10. It
got too complicated with the X10, and I didn't really like the cool white.
The blue LED's are really neat. I have never seen that mystical color
temperature
out of LED's before.

They are changing over the emergency vehicle beacons here in the UK now to
blue LEDs, and as you say, the colour is such a brilliantly intense blue,
that they are far more visible as being emergency vehicles over a much
greater distance, than ever the blue plastic-filtered zenon flashes were.

Arfa