LED Lighting Lumen Output

[Serenity Malc]

Yello,

 

I'm currently fitting my barge for 12V lighting throughout as my situation appears to be about to radically change from being a shore line dependent, to a battery dependent.

 

I'm using 6 new GU10 light fittings which were originally designed as 240V items, but wiring them to 12V. These days one can buy 12V GU10 LED's from the orient as opposed to most UK sellers only supplying them for 240V use.

 

My question is: I'm doing the maths to decide whether I should buy 3 Watt, 4 Watt, 5 Watt, 6 Watt, 8 Watt or 12 Watt LED lamps in any one of the locations. When I check the tech spec of each lamp for lumen output, I notice some annomolies (sp?) in their stated light output.

 

EG: 3 WATT = 300 LUMENS

4 WATT = 300 LUMENS

5 WATT = 500 LUMENS

6 WATT = 500 LUMENS

8 WATT = 500 LUMENS

12 WATT = 800 LUMENS

 

Do I simply assume that the fewer LED's that make up each lamp would produce a more efficient lumen output ? The LED type could be the reason for varying efficiencies ? The manufacturers are being casual with their tech specs ? or all of the above ?

 

It would appear that the 3 Watt or 5 watt items would be the most efficient in general terms, until a higher brightness was required. Although seeing as the manufacturers have obviously rounded up or down the lamp efficacies, who knows !

 

My initial reason for doing the maths was to calculate the current draw for the new 12V lighting circuit and hence the cable size. The figures above are taken from two major oriental suppliers and oddly enough concur with each other.

 

According to the quoted lumen output figues, the difference between for example 6 x 5 Watt lamps and 6 x 8 Watt lamps would be 1.5 Amps ! .... for the same lumen output. 1.5 Amps @ a nominal 12V is to me a considerable difference.

 

Please enlighten me !

 

Cheers Malc.

Edited January 16, 2013 by Serenity Malc

[Keeping Up]

One factor that can affect this is the colour of the light. For the same electrical input power a brilliant white will have a far higher Lumen output than a warm white.

[Serenity Malc]

Yello,

 

ALL of these figures are based on a warm white colour around 3000k - 3200k.

 

Thanks Malc.

[bottle]

Slightly tangential

 

Forget the cheapies from abroad that are not designed for boat use.

 

Go to http://www.bedazzled...nt.htm#ADAPTORS, towards the bottom of the page and buy the adapters and some decent LEDs designed for boat use.

 

In the overall cost of fitting out a barge the extra cost is negligible.

 

ps. other suppliers are available.

 

pps. give Bedazzled a 'ring' and talk to someone that knows.

Edited January 16, 2013 by bottle

[nicknorman]

Yello,

 

ALL of these figures are based on a warm white colour around 3000k - 3200k.

 

Thanks Malc.

There is warm white colour, and then there is warm white colour! Incandescent lamps (tungsten, halogen etc) emit a broad spectrum of light frequencies that we see as warm white. I think these warm white LED lamps work by emitting ultraviolet light at a single frequency, onto a coating that fluoresces. According to the materials in the fluorescent coating, this will emit light at a range of frequencies - a sufficient range to look roughly "warm white" to the human eye, but much more the case of a few specific frequencies, rather than the wide spread of frequencies from a real warm white incandescent bulb. Just how good these warm white LEDs look is quite variable, I presume depending on the exact materials chosen for the fluorescent coating.

 

I cannot be certain but would hazard a guess that some of these materials are more effective than others at emitting visible light. So if you choose only those, you get plenty of light but at relatively few frequencies. The light is allegedly warm white but can look nasty due to the limited number of frequencies. However if you choose lots of materials for the coating (some being less efficient) you get light at many more frequencies, it looks much nicer but you get less overall light.

 

I hate stark lighting so I have purchased a number of different types of warm LED lights. Some are really horrible, though bright! The best ones I found, which really are indistinguishable from halogen lights in a side-by-side test, are however towards the dimmer end of the spectrum (excuse pun!).

 

So perhaps (and not sure here) the moral is that you can have high brightness crap light quality, or great quality at lower brightness. Therefore, if you are of a sensitive disposition like me, it may be best to avoid the ones with the highest brightness per watt on paper. In any case, I would recommend trying different types out before you buy a whole bunch of one type - there really is a big variation.

Edited January 16, 2013 by nicknorman

[bowten]

Some of these these domestic LEDs will not take the range of voltage produced by the alternator.

[alan_fincher]

Yello,

 

ALL of these figures are based on a warm white colour around 3000k - 3200k.

If it is "warm white" you want, I think you acre confusing people by keep saying "Yello" in every post, then!

[Rebotco]

If it is "warm white" you want, I think you acre confusing people by keep saying "Yello" in every post, then!

 

 

I expect if you've got an attack of the galloping DTs, its quite easy to hit the Y instead of the H.

[Serenity Malc]

Yello,

 

Thank you NickNorman for your thoughts ... I'd no idea how a modern LED achieves it's colour. Your expaination makes a lot of sense.

 

I've heard that voltage fluctuation, or maybe more specifically over voltage can damage the colour of an LED. My application is quite urgent so although I've thought about fitting a stabilised supply unit, it probably won't happen until a month or so has passed.

 

I'll check out Bedazlled .... thank you Bottle.

 

Most LED's I've seen in the 12V nominal bracket will accept up to 30V DC, so I'm not sure about the alternator output comment. In any case I do intend to install a regulated supply unit as a matter of course.

 

As always your superior knowledge and experience is SO welcome ... thank you guys.

 

Malc.

[Serenity Malc]

Yello,

 

I've checked out the Bedazzled website and not found any 12V GU10 lamps. Just an adapter from a standard mains fitting. In fact I've yet to find a UK supplier. Now ... normally a GU10 fitting is used in a 240v application. Maybe an MR16 would be the norm in a 12V fitting. But seeing as I've just purchased 6 x satin chrome switched bullet spots with GU10 fittings (£57 delivered) and can purchase GU10 LED's quite easily from the orient, that's what I'm going to do.

 

Being poor as a church mouse makes one creative.

 

Malc.

Edited January 16, 2013 by Serenity Malc

[nicknorman]

 

Most LED's I've seen in the 12V nominal bracket will accept up to 30V DC, so I'm not sure about the alternator output comment. In any case I do intend to install a regulated supply unit as a matter of course.

 

 

Yes most these days have built in regulation so that they can cope with up to 30v. The max stabilised voltage you are likely to see on your system is around 15v, maybe 16v if you do a battery equalisation charge. The regulators have the added advantage of meaning that when the water pump kicks in / inverter-fed electric kettle is turned on (if you are an electric kettle fiend like we are) the lights don't dim, even though the supply voltage has dipped a bit.

 

There has been a lot of discussion on this forum about the voltage transients produced by things such as fridge thermostats operating, however although these things most certainly do exist, they do not normally seem to be a problem. Transients are quite hard to eliminate and using a regulated supply will most certainly not get rid of them. Therefore, if you use regulated LEDs that can take up to 30v, there is nothing to be gained by feeding them from a regulated supply, and a fair bit to be lost in terms of cash!

[Bobbybass]

Some of these these domestic LEDs will not take the range of voltage produced by the alternator.

I use LED units..I bought from Spain..(Chinese bazaar )...about 1 Euro each...

They wouldn't take much over 12.5 volts..but I made voltage limiters....using LM2940-12 regulators.

Depends how handy you are with a soldering iron.?

It is only 3 components...the LM2940 low dropout regulator and two small capacitors...all available on Ebay...(and an inline... low current fuse )

As its 3 pieces..you don't need to mount it on a 'board'.

The output...electrolytic capacitor..I used 100uf...instead of 22uf..and this stops them dimming when other things switch in.

The finished 'item' is so small and cheap..I just made one for every light and fitted each in the lamp itself.

 

I installed mine a few years back and no problems...

Regulates nicely to 12 volts or slightly less...no matter what the battery voltage.

 

Here go:

 

http://www.ebay.co.uk/itm/LM2940CT-12V-1A-Low-Dropout-Positive-Voltage-Regulator-/180652117829?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2a0fb48f45

Edited January 16, 2013 by Bobbybass

[nicknorman]

I use LED units..I bought from Spain..(Chinese bazaar )...about 1 Euro each...

They wouldn't take much over 12.5 volts..but I made voltage limiters....using LM2940-12 regulators.

Depends how handy you are with a soldering iron.?

It is only 3 components...the LM2940 low dropout regulator and two small capacitors...all available on Ebay...(and an inline... low current fuse )

As its 3 pieces..you don't need to mount it on a 'board'.

The output...electrolytic capacitor..I used 100uf...instead of 22uf..and this stops them dimming when other things switch in.

The finished 'item' is so small and cheap..I just made one for every light and fitted each in the lamp itself.

 

I installed mine a few years back and no problems...

Regulates nicely to 12 volts or slightly less...no matter what the battery voltage.

 

Here go:

 

http://www.ebay.co.uk/itm/LM2940CT-12V-1A-Low-Dropout-Positive-Voltage-Regulator-/180652117829?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2a0fb48f45

The only trouble is that the 2940 drops about 0.5v minimum, so if your bats are below 12.5, you will end up with less than 12v at the LED. Not a massive problem but the switch mode regulators built into the LEDs that run up to 30v have virtually no dropout.

[Bobbybass]

The only trouble is that the 2940 drops about 0.5v minimum, so if your bats are below 12.5, you will end up with less than 12v at the LED. Not a massive problem but the switch mode regulators built into the LEDs that run up to 30v have virtually no dropout.

They have dropped down to 12.2 once or twice but no noticable drop off of light.

In several years..there has been no drop off...

My 12 volt batteries don't often get to 30v ?..not sure why I should have to worry about that..or plan for it.. ?

Do you think you are going to notice a LED with resistor running on 11.7 volts instead of 12..?

 

I didn't see the point of spending such a huge amount of money..on LEDs that did that...when I could get them for 1 Euro...and use the regulators..

Edited January 16, 2013 by Bobbybass

[nicknorman]

 

I didn't see the point of spending such a huge amount of money..on LEDs that did that...when I could get them for 1 Euro...and use the regulators..

Fair enough - I was really just pointing out to OP the minor cons after you had made the case for the pros!

[Chalky]

Ignore the wattage, look at the lumens. I build LED bike lights and often buy power LEDS. LEDs are selected once they've been manufactured since there's a considerable spread in light output from the manufacturing process. The best ones will produce a high lumens output for a low wattage input. The seoul P4 4W LED that I use is available in 60 lumens, 90 lumens, 110 lumens and 240 lumens - the price rising for the output increase. The 240 lumens ones are very efficient at converting electrical power to light, the 60 lumens ones aren't. You get what you pay for.

As well as lumens also look at the heat sink connected to the LED. They are sensitive to heat and a small heat rise (for a semiconductor) can drop the light output by 20 - 30%

Edited January 16, 2013 by Chalky

[Bobbybass]

Fair enough - I was really just pointing out to OP the minor cons after you had made the case for the pros!

OK...equally fair enough then....

 

I know the regulator drops .5 volt..but as I say...I never let my batteries below 12.2 volts ...so that only means 11.7 volts as worse...

 

Having said that..I tested each little regulator 'on the bench' before installing into the lights..and all of them were a little better than the spec...dropping less than 0.5 volts...when I set the bench supply lower than 12v.

All of them actually ...supplied slightly less than the 12 volts..generally around the 11.93 - 11.97 mark....if my meter was to be believed....(AVO that I used to set up mainframes with )

Edited January 16, 2013 by Bobbybass

[lexicon]

ok so heres a lumen related question that i would be interested in knowing how many lumens are needed per foot in a nb to give good usable light level?

[Bobbybass]

ok so heres a lumen related question that i would be interested in knowing how many lumens are needed per foot in a nb to give good usable light level?

 

Hmmm...?

 

About 3 simplets...and a tad....

[bowten]

Hmmm...?

 

About 3 simplets...and a tad....

Are you sure about the tad?

[Keeping Up]

Here are a few random numbers which may or not help.

 

Baddie the Pirate sells LED tubes that are claimed to be equal in light level to 2 fluorescent tubes, and to give 220 lumens each. So from that a two-tube unit should give 220 lumens of output.

 

Our narrow-boat lounge is about 16ft and has 4 ceiling fittings, each having 2 tubes until I just replaced them by LEDs, so that would be 880 lumens of output. The light level from those alone was acceptable, although for reading very small-print books I often needed to put the wall lights on as well. But that would be 880/16 = 55 lumens per foot in a living area.

 

Our kitchen is about 6ft 6in and has 2 similar fittings, which gave plenty of light for working. This suggests perhaps 65 lumens per foot for a working area.

 

The bedrooms have about half this level, maybe 30 lumens per foot.

 

This is all based on the assumption that Baddie's specification is accurate (I have no personal knowledge of them)

[Titan]

Yello,

 

I've checked out the Bedazzled website and not found any 12V GU10 lamps. Just an adapter from a standard mains fitting. In fact I've yet to find a UK supplier. Now ... normally a GU10 fitting is used in a 240v application. Maybe an MR16 would be the norm in a 12V fitting. But seeing as I've just purchased 6 x satin chrome switched bullet spots with GU10 fittings (£57 delivered) and can purchase GU10 LED's quite easily from the orient, that's what I'm going to do.

 

Being poor as a church mouse makes one creative.

 

Malc.

 

Mike i have just fitted leds to all my spots, which were g4 i think, the light colour is wonderfull but quite (dim ) compared to original, however its dissapointing but like you im fitting out, ive reordered again from same oriental suppier the next brightness (lumens ) up, to compare at £1. each i dont mind experimenting, i sort of dropped a bo""ok when i ordered some lovely switched wall spot lights from germany, they arrived and look great but bulb fitments were G9 an even rarer led fitment, again sourced from china £14.00 for 5 i patiently await there delivery The spec on all the led tallies with what you say 10/30 v. Il get back in touch when they arrive and offer more light on the issue (forgive the pun )