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Posted by Jim Wilkins on February 12, 2009, 2:26 pm
 

It's simpler to control hallway lamps and at least one light per room
with pyroelectric motion detectors so the light turns on automatically
when anyone enters and shuts off after a delay. My preference is to
have that light fairly small, enough to see when you walk in to pick
up something, but not be the main light so the room won't go dark when
you sit still.

These night lights are bright enough for me to walk around without
turning on other lights;
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95195
The KAW reads 0.01W, 0.07A.

Jim Wilkins

Posted by Tim Jackson on February 12, 2009, 4:29 pm
 
Jim Wilkins wrote:

Yes, I do some of that. I use 3W CFL's for night safety lights.

But electricity is the least of my worries while I'm using so much
natural gas for heating this old Victorian pile of rocks.

Are you sure that wasn't 0.01kW? 10mW isn't much light even for a panel
lamp.  LEDs are generally less efficient than fluorescents.

Tim

Posted by Jim Wilkins on February 12, 2009, 6:04 pm
 
"01 Watt". It only lights up in dark places and I misread the
display.

I don't have any other way to read such low line currents except by
patching a multimeter in with a Death Cord. The nightlight is marked
0.3W, a KWH every 3000+ Hrs or less than two a year if it sees
daylight. The package claims less than $.25 per year to use.

It has lifetime guarantee, meaning the guarantee ends when the light
dies.

Jim Wilkins

Posted by Tim Jackson on February 12, 2009, 7:17 pm
 Jim Wilkins wrote:

Fair enough.

LED's generally don't die, they just fade away as they age.  So if the
guarantee is that it will put out "some" light, they are on to a winner.

To judge from the current reading it uses a capacitor current source to
directly feed LEDs.  Obviously the power factor is dreadful, 0.3W / 7VA,
but that's not a problem at very low powers on domestic wiring.


Tim

Posted by Steve Ackman on February 13, 2009, 12:03 pm
 on Thu, 12 Feb 2009 10:04:09 -0800 (PST), Jim Wilkins, KB1DAL@gmail.com
wrote:

  Or see what you've got for energy consumption after
leaving it plugged into the Kill-A-Watt for 10 hours?

--
☯☯



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