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Forum Index : Electronics : Devices wih LED’s

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Georgen
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Joined: 13/09/2011
Location: Australia
Posts: 462
Posted: 07:52am 22 Mar 2012
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I have several devices that have LED lights when power is on.

Probably originally sounded as good idea, but if I have remote door bell always in power point and it is always on, I don’t really need this green light to tell me it is on.

I have 4 or 5 of those that I have green or red light and I wish I could disable them

Did anybody done just that?

Or it is only me that cringes on dozen of kWhours in a year gone for nothing.

George
 
Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904
Posted: 01:55pm 22 Mar 2012
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  Georgen said   I have several devices that have LED lights when power is on.

Probably originally sounded as good idea, but if I have remote door bell always in power point and it is always on, I don’t really need this green light to tell me it is on.

I have 4 or 5 of those that I have green or red light and I wish I could disable them

Did anybody done just that?

Or it is only me that cringes on dozen of kWhours in a year gone for nothing.


A quick calculation using generous parameters tells me that a single LED consumes less than 0.2KWh/year. Hardly worth bothering about. Trying to get into often difficult to open items to disable the LED within can be a challenge and completely disable the unit .

An electronic timer (the digital type with LCD screen) running all the time uses around 50Kwh/year. Worthwhile to look at alternatives.
Klaus
 
Georgen
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Posted: 04:06am 23 Mar 2012
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Not exactly, according to my meter.

I used ALDI power meter and most devices with single LED even power boards use above 0.5W

0.5 W x 24 hours x 365 days = more than 4 kWh in a year for one device


George
 
Tinker

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Posted: 11:49am 23 Mar 2012
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  Georgen said  
Not exactly, according to my meter.

I used ALDI power meter and most devices with single LED even power boards use above 0.5W

0.5 W x 24 hours x 365 days = more than 4 kWh in a year for one device



Ah, now you say "devices". There can be a vast difference in the power draw of a "device" and just the LED within. You originally just wanted to disable the LED as I read it.
Klaus
 
Georgen
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Posted: 09:38pm 24 Mar 2012
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  Tinker said   Ah, now you say "devices". There can be a vast difference in the power draw of a "device" and just the LED within. You originally just wanted to disable the LED as I read it.


Well, yes and no.

This measurement was just from 4 outlet power board with LED red light so it was purely LED.

I also mentioned remote door bell, this one has green LED.
I did not measure this one, but suppose it will be close to 1W, as it has LED plus some power will be drawn by listening device for signal from button on the door.

Have few more power boards and devices and power wasted just adds up.
George
 
Tinker

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Posted: 02:14pm 25 Mar 2012
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  Georgen said  
Well, yes and no.

This measurement was just from 4 outlet power board with LED red light so it was purely LED.



Now we are getting to he heart of your question .
If its just a LED in the power board and the power board is made for mains AC voltage then how do you suppose the approx. 2.5VDC for the LED is obtained?
Its either just a dropping resistor/diode or a resistor/capacitor/diode combination.
The resistor is what's consuming the lion's share of the power waste, not the LED.

So I was right in the first place .

P.S. it avoids a lot of confusion by being more concise when asking for information here
Klaus
 
Georgen
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Posted: 12:05am 26 Mar 2012
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Looks that the only way not to have LED glowing all the time is to buy device without one which right now is next to impossible.

Hope in future there will be extra swich that gives you choice to have LED on or off.

Does anybody else have some solution to successfully remove LED from power board / device?
George
 
Warpspeed
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Joined: 09/08/2007
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Posted: 02:30am 26 Mar 2012
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Just disconnect the LED.
One quick snip with a sharp pair of nippers would do it.

I have a light switch in my garage with a neon indicator so I can more easily find the switch in the dark.
I was once curious about the cost of running that neon continuously.
It has a 470K resistor, so draws about 0.5mA.
That is 120mW
Just over 1KwH per year.
About fifteen cents per year.

Cheers,  Tony.
 
Georgen
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Posted: 09:07am 26 Mar 2012
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  Warpspeed said   ...

I was once curious about the cost of running that neon continuously.
It has a 470K resistor, so draws about 0.5mA.
That is 120mW
Just over 1KwH per year.
About fifteen cents per year.



I am bit suspicious that ALDI power meter doesn't properly measure low range use of power.

Tinker and you say that usage is about ¼ or less of what I get.

Will have to take few more measurements.

I will get several appliances with single LED, measure their usage individually and then couple them all together and take total measurement.

If measurement will be the same as sum of all measurement, will have to reluctantly accept it.

Will probably have to get Meter and measure current.
Somehow I don't like to measure anything on mains power, but if it is only way to find out if ALDI power meter is accurate, suppose have no choice.
George
 
Tinker

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Posted: 02:05pm 26 Mar 2012
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Yes, many of the earlier power boards had neon lights in them and these draw so little power that its not worth the effort to remove them.
Neon lights have a more orange color rather than the deep red of LED's.

The other thing to consider is that power boards are not meant to be tampered with and many are fitted with one way screw heads, making it just about impossible to get at the innards and the LED.
I suggest if you are really bothered by this power waste you buy only power boards that have no 'ON' indicator light. These are usually cheaper too.

Re your low power measurements, I doubt that your "aldi" meter is designed for measuring low currents.
You'll need an AC Amp meter in series with one power wire for precise measurement but that involves fiddling with dangerous mains voltages. Unless you are an electrician I would strongly advise against it.
Klaus
 
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