# How bright are normal LEDs



## 107877 (Oct 25, 2007)

I notice that LEDs are the new in thing. Can anyone advise me the what the brightest leds available compared to normal haolgens


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## mangothemadmonk (Aug 6, 2006)

Have a look

Here

I only have the 4 led ones are they are bright enough for me to read by.

There is cool white light and soft white light. The cool white is a blue light.

I think the G4 halogen bulbs are rated from 5 to 35 watts and the 21 LEDs are rated at 15w

I bought them for their low energy consumption and must agree they DO work well.

Johnny F


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## Boff (May 10, 2005)

Hi,

determining the brightness of a light source with the naked eye is practically impossible. The eye simply adapts too quickly to changes in light intensity, it is sensitive to the colour spectrum of the light source, and many more. In addition, it reacts on a logarithmic scale, so what we feel of being +100% in brightness is in fact an increase of a factor 10 in light intensity.

The only physically sound and reproducible quantity that can be used to determine the total output of visible light is the so-called luminous flux, measured in units of "lumen" (lm). This luminous flux considers the spectral sensitivity of the human eye, so it does not represent the total power of light emitted (that would be the "radiant flux"), but only that which is really visible.

Dividing the luminous flux by the electrical power consumed by the light source delivers a quantity called luminous efficacy, measured in "lumen per watt" (lm/W), and this is the quantity needed here.

Now looking at _white LEDs_, it was not before the end of 2006 that the first LEDs were released to the market that exceeded normal halogen bulbs. These LEDs, e.g. the OSTAR from Osram, achieve up to 50 lm/W, while a halogen bulb has about 35 lm/W. (Ordinary incandescent light bulbs are around 15 lm/W, so out of discussion here...) So meanwhile it does make sense to replace halogen lamps by LEDs for better efficiency.

However, these LEDs are still not exactly cheap, and currently at least they still fall short of fluorescent tubes regarding luminous efficacy. But this will probably change over the next year or so.

Best Regards,
Gerhard


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## 96783 (Nov 23, 2005)

Thanks Boff. The best explanation I have seen yet. Like beauty it certainly depends on the eye of the beholder. We had LEDs (G4 - 21 LEDs) in our last van and swore by them. Our local friendly Knaus supervisor said they were not as bright. We tried three under our kitchen units at home and my wife said they didn't give enough light, although she said they did in the 'van (work that one through!) but I found them perfectly adequate. Until you've tried them in the environment in which you want to use them it will only be a theoretical exercise.

Having said all that, we will be converting halogen to LED in our next van!!


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## Telbell (May 1, 2005)

> Until you've tried them in the environment in which you want to use them it will only be a theoretical exercise.


That's dead right phredC, and the point I made to UltraLEDs when I read their terms/conditions alomg the lines of "if you use them at all, for whatever reason, we won,t exchange"

To be fair they applied some common sense and I'm currently waiting for a few replacements whcih I sent for as the ones I ordered just weren';t bright enough


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## ICDSUN (Oct 10, 2006)

Hi

I have fitted these in our spotlights and in fact they are slightly brighter than the original spotlight bulb, found them excellent

http://www.ultraleds.co.uk/ultra-bright-mr11-acdc-cool-white-bulb-p-1458.html

I also fitted these G4 units and find them really bright, we did try the warm version but they were little too dim for the main cabin ceiling lights so we have moved them to the units over hob/kitchen, the cool version is as good as the halogens we replaced

http://www.ultraleds.co.uk/cool-white-bulb-8v30v-p-1457.html

They are not cheap, but we don't use hookup very often so they work for us

Incidentally I did try the 21 bulb 10w equivalent unit and found it poor in comparison to the above G4 unit that I ended up with (20w equiv)

Chris


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## ojibway (May 9, 2005)

That was a very illuminating explanation by Boff. Thanks.
As these LEDs are very expensive you need to get the right ones. They are improving all the time.
We have been using LEDs for over 2 years now. We got them from ULTRALEDS. The first ones fizzled as they couldn't cope with the fluctuating voltages.
Currently have 4 G4s in our Westfalia James Cook. I'm also trying to figure out how I can change the flourescents for LEDs.
Only problem with the G4s is that I have to leave off the glass cover.

I really don't know why the MH manufacturers insist on putting in Halogen spot when the consume so much. I guess its because they look good!
Mike


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## Boff (May 10, 2005)

Hi!



ojibway said:


> I really don't know why the MH manufacturers insist on putting in Halogen spot when the consume so much. I guess its because they look good!Mike


I think the explanation is much simpler: Halogen spots are cheaper...

And, of course: When the current MH models were developed (1-2 years ago), LEDs did not yet have any advantage over halogen spots regarding efficiency.

Best Regards,
Gerhard


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## DJP (May 9, 2005)

If you buy them in the UK they are expensive. How about $49 for 12 + postage? I ordered from them. They came within a week and are excellent. See LED LIGHTS


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## homenaway (Jul 27, 2005)

Hi,
I have been looking at the LED options and have bought one of the circular LED battery camping lights from Wilkinsons for about £4 - haven't tried it for serious reading yet but it is a very bright blue/white.

Following Boff's link to the Osram site has anyone tried the Osram DOT-IT lights and are they a warmer white?

They had loads in our local B&Q for £4.98 each (less 10% on Wednesdays if you're old enough  

The latest circular ones are dimmable to 3 light levels but not sure if the B&Q ones were. Only trouble is the need three AAA batteries but claim to have 100 hour life - I guess they could run off rechargeable AAA's or a 5v regulated power supply with a bit of modification!

Steve


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## 107877 (Oct 25, 2007)

thanks every one for your reply. was looking at the ultraled webpage but found that these multi dot bulbs dont look as good as the bulbs from another site in the UK. the company is at LINK REMOVED BY MODERATORS , is the bulbs they do which are Leds better than the dot versions. or are they the same in light output?

LINK REMOVED BY MODERATORS


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## DJP (May 9, 2005)

> thanks every one for your reply. was looking at the ultraled webpage but found that these multi dot bulbs dont look as good as the bulbs from another site in the UK. the company is at LINK REMOVED BY MODERATORS , is the bulbs they do which are Leds better than the dot versions. or are they the same in light output?


The LED's mentioned here are MR16 and are 50mm in diameter. It is important to dheck the physical size of your lamp. The ones in my post are MR11 at 35mm diameter, which I think is the most popular.
Nice lamps though marlboros.
Dennis


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## 107877 (Oct 25, 2007)

Right im gonna order a couple MR11 and Mr16 for test from LINK REMOVED BY MODERATORS and test to see if they any good.


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## sersol (Aug 1, 2005)

Hi all,a word of caution to those buying CHEAP led replacements.
You MUST make sure that they are higher rated than 12v dc. 12-30v is more the area you should consider,when on hookup (if you are) the voltage can be upto 15 odd volts.
The early leds I had were only rated to 12v & on the rare occasion I was on ehu it did not take long for the led's to start "smoking".
To their credit "Ultraled's"replaced them.
Gary


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## 107896 (Oct 26, 2007)

Wow thanks Marlboro for the link. LINK REMOVED BY MODERATORS does some amazing LED Lamps. They also come with 1 year warranty !!! But the problem is they have so many on range, I find it confusing which one is the correct one for me. 

I am looking at their LINK REMOVED BY MODERATORS, It's amazing that they claim it only consumes 1watt of energy which will be ideal for my motorhome. But the question is will it be brighter than the ones with the dots? Spending around £14 each is quite steep, but for the power saving I get it might be well worth the money.

Has anyone else tried out these MR11's before?

LINK REMOVED BY MODERATORS


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## 96511 (Oct 12, 2005)

Interesting article on LEDs here...
http://news.bbc.co.uk/2/hi/uk_news/scotland/glasgow_and_west/7162606.stm


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## gaspode (May 9, 2005)

Hi All

Just to explain why I have deleted all the links in the posts by two members in this thread. If you hadn't already realised they appear to be the same person and clearly out to dupe members into purchasing from the company linked to by making false recommendations.


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