LED Lights

[Mike90250]

There are places for both LED, CFL and T-5, T-8 tubes. Each application will be different. For the flood over the sink/stove the LED spot with your favorite color/CRI is very good (and that heatsink is way bigger than 3 watts). The same spot/flood will wash a wall nicely, and you can move around in a room or 2 at night, for 3 watts. But other applications have other bulbs that work best. There is no "One" best replacement, it's going to be application driven, of what your needs are.

[Crumb]

One of the things that need to be addresse is the need for light. I have already said that we have single LED backup lights upstairs, which just provide enough light to see at night. A new visitor to the house yesterday said he was really impressed as to how little light is needed to walk from A to B. In fact switching on a CFL would be pointless, as by the time it was up to full strength, it would have been switch off again. By the way I have seen that Fluoresecents including CFL have an initial surge of current, and need to be switched on for "23 minutes" to make then cost effective. Is this true?
However I am starting to realise that light required to go from A to B, is very different from light required to find something dropped on the floor between A and B. The problem it seems to me is that maximum light is a given, even though rarely does it need to be that bright. Obviously for activity in the home such as reading or cooking, requires much more light than using a computer or watching TV. So maybe there needs to be a 12 v backup lighting system which provides a continuous low level light and a "mains" system which provides much brighter light on demand

On a moonless night, with dark adapted eyes, you need very very little light to move around. You can see about 5-10 feet with a bic lighter, which is pretty much nothing. You won't see good detail, or be able to sew a button back on your shirt, but you can place your feet around rocks and branches.

This is also a good idea for a boat at night. Tiny amounts of light can wipe out your night vision, and when you are standing watch this can break stuff and kill people. So you can have enough light to read a chart, or go grab some coffee, but you still have most of your night vision. Granted, I would have the new generation LED's in a warmer CCT and good CRI.

This is where the LED has another advantage. They can be run at much less than their rating, for much less output, and last much longer than what they are rated for, with much less heat. It is all in the datasheets I linked. I was amazed.
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I know a little more about CFL's - The money savings is in long runs with low cycles. On/Off cycles seem to matter more than the industry is willing to admit.

I have a few 12(ish) year old CFL's with many many hours of burntime on them - but only one cycle a day using a timer/photocell. 8 to 12 hours a night constant on for outdoor lighting at night. I would say there is an advantage with that.

[Sunking]

By the way I have seen that Fluoresecents including CFL have an initial surge of current, and need to be switched on for "23 minutes" to make then cost effective. Is this true?

Complete hogwash. Start up current of 2 X last only for a few milli-seconds. That means less than 1 second.

[dogsbody]

One of the things that need to be addresse is the need for light. I have already said that we have single LED backup lights upstairs, which just provide enough light to see at night. A new visitor to the house yesterday said he was really impressed as to how little light is needed to walk from A to B. In fact switching on a CFL would be pointless, as by the time it was up to full strength, it would have been switch off again. By the way I have seen that Fluoresecents including CFL have an initial surge of current, and need to be switched on for "23 minutes" to make then cost effective. Is this true?
However I am starting to realise that light required to go from A to B, is very different from light required to find something dropped on the floor between A and B. The problem it seems to me is that maximum light is a given, even though rarely does it need to be that bright. Obviously for activity in the home such as reading or cooking, requires much more light than using a computer or watching TV. So maybe there needs to be a 12 v backup lighting system which provides a continuous low level light and a "mains" system which provides much brighter light on demand

[Sunking]

250-350 milliamps? Yes please!

Unless a voltage is specified that means nothing. I am familar with this landscape light. It is designed to operate on landscape lighting 12 volt system. It emits 110 Lumens and consumes 4.2 watts on a 12 volt supply. That gives you an efficiency of 110 Lumens / 4.2 watts = 26.1 L/W. Roughly the same as an incandescent Edison light bulb at 25L/W

[Crumb]

Crumb many of us have very different opinions about lighting.. What one likes is not necessarily the same as the next person. I really believe for most home user(NOT FOR OFFICES) people buy lights for what they like and use a brightness that they are happy with.
In my whole life I have never heard of a home owner buying lights because that put out so many lumens .
Most of Sunkings statements are true about LEDs but not all. Some make no sense at all to me.. His favourite light is tube T5s. So they are efficient, but the light look like yuk in a house.Well thats my opinion.
I have been using Cree LEDs for more than 3 years now in places that had tube fluros then CFLs and the LEDs provide the amount of light I need at less than 1/2 what the CFLs used.. they are all MR16 replacements that run off 12v DC. Never had a failure they also run cool and the light output seems the same now as it was over 3 yrs ago.
Mr Crumb if you are happy with the LEDs you are using then all is ok,, dont change because someone told you they are not the right choice... May the light be with you.

I very much understand using the right tool for the job, and I am very impressed with that I have seen so far with the new generation LED lights. Learning about them seems like a good project later this fall for when I get some time after this solar stuff.

It seems readily apparent that they are not good general area lighting. They are trying now, but it will be a long time before they can do an LED edison bulb that is sensible.

Why? They are highly directional, like a flashlight. I can see them being great floodlights, great spotlights, and nice wall-washes, but for large areas they aren't the greatest unless it is in an emergency capacity.
I wouldnt want to try to light a room with one, anyway.

Now, would I use them in a cabin, an RV, a boat and other small areas in combination with solar, especially a 12V system? You bet!
Just the few dozen hours I have played with my little Malibu light has me convinced.
250-350 milliamps? Yes please!

It is a nicely diffused directional flood with a hologen color, and not blue in any way. I left the threaded plastic base on mine and sawed off the spike. Screwed the base through the lid of my shoebox kit and cranked down the light on top - A little sillicone around the base and it is indoor/outdoor.

By the way, it has a low starting voltage. Could probably get a little less than half power on 6 volts, if that is anyone's thing.

[john p]

Crumb many of us have very different opinions about lighting.. What one likes is not necessarily the same as the next person. I really believe for most home user(NOT FOR OFFICES) people buy lights for what they like and use a brightness that they are happy with.
In my whole life I have never heard of a home owner buying lights because that put out so many lumens .
Most of Sunkings statements are true about LEDs but not all. Some make no sense at all to me.. His favourite light is tube T5s. So they are efficient, but the light look like yuk in a house.Well thats my opinion.
I have been using Cree LEDs for more than 3 years now in places that had tube fluros then CFLs and the LEDs provide the amount of light I need at less than 1/2 what the CFLs used.. they are all MR16 replacements that run off 12v DC. Never had a failure they also run cool and the light output seems the same now as it was over 3 yrs ago.
Mr Crumb if you are happy with the LEDs you are using then all is ok,, dont change because someone told you they are not the right choice... May the light be with you.

[Sunking]

Well their fly-by-night hackery saved me from your designs,

Where did I say Fly-by-night hackery?

You do not seem interested in hearing reality other than make believe, or even bothered asking what i meant. Go look at the specs in your link. Heck I will point it out for you. It is the cool white XPGWHT-L1-0000-00G51 rated at 139 Lumens per watt. That statement is true, but only half the story. That is only for the LED chip module component. It is not in a luminaire. That means a working lighting fixture.

A lighting manufacture will take the chip and design a luminaire for the chip. To make it work the manufacture has to use some sort of ballast driver, the thingy to take either DC voltage or AC voltage and convert it to a current driver. To do that takes electrical power above and beyond what the LED consumes. That is where the efficiency gets lost and the half turth comes in.

The very high end manufactures use a ballast driver of about 50% efficiency. At that efficiency level that 1 watt LED now becomes 2 watts, and at 2 watts the lighting efficiency is now 70 Lumens per watt, which is right where CFL's are and far below T5 and T8 Fluorescent lights.

To add insult to injury very few manufactures use such high end ballast, they use inexpensive ballast to keep cost down. So instead of using 1 watt consumed they uuse 2 or 3 watts. Guess what that does to the overall efficiency. Drops it down to 40 Lumens per watt or less right about the same as an incandescent light bulbs.

[Offgrid]

Guys this is a place for sharing information,the time and information provided on here is of free will and our own personal time that we devote to trying to help each other. We may not always agree with each other but lets treat each other with respect.Sometimes what works in one application doesnt always work so well in another there are tons of vendors and technologies out there with varying results.Lets cut each other some slack here.Remember opinions are like A-holes...everyone has one but you dont necessarily want to share one.

[Crumb]

No I am not out of date. I am a certified IES engineer and if I were to fall behind would be out of business as lighting is a large part of an engineering design firm working on government buildings. Cree claims are half truths but not real applications.

Well their fly-by-night hackery saved me from your designs, and spending quite a bit of money.
It's very telling that you are a government engineer and that explains everything I need to know about the value of your information. Welcome to my ignore list. It's been fun.

[Sunking]

I was just looking at this yesterday for the little malibu light I got because I was so impressed. You have outdated information.

Here is the data sheet for the popular Cree XPG

http://www.cree.com/products/xlamp_xpg.asp

90 cri and and nice warm light is there if you want it.
Don't need a very big heat sink at rated current (350ma) either.

Edit: to be honest I need to do more research myself. These are very promising in combination with solar.

No I am not out of date. I am a certified IES engineer and if I were to fall behind would be out of business as lighting is a large part of an engineering design firm working on government buildings. Cree claims are half truths but not real applications.

[Crumb]

Heat is the downfall of all LED lights. Manufactures publish efficiency at maximum current levels @ 1 milli-second pulses before th eLED has time to heat up. When an LED heats up, light level falls off the cliff, not to mention significantly shorten the life time to a flash bulb.

Current LED's on the market today are no more efficient than CFL's, and in some cases no moere efficient than incandescent bulbs. Most also have tremendous amounts of Blue Light Pollution. and you cannot see worth darn in blue light.

To take it one step further the US Federal Government will not allow LED lights in any federal buildings. Want to know why? Because they do not meet minimum efficiency standards. That pretty much says it all. Only some CFAl and T5 and T8 Fluorescent lighting meet Federal standards.

I was just looking at this yesterday for the little malibu light I got because I was so impressed. You have outdated information.

Here is the data sheet for the popular Cree XPG

http://www.cree.com/products/xlamp_xpg.asp

90 cri and and nice warm light is there if you want it.
Don't need a very big heat sink at rated current (350ma) either.

Edit: to be honest I need to do more research myself. These are very promising in combination with solar.

[Sunking]

Heat is the downfall of all LED lights. Manufactures publish efficiency at maximum current levels @ 1 milli-second pulses before th eLED has time to heat up. When an LED heats up, light level falls off the cliff, not to mention significantly shorten the life time to a flash bulb.

Current LED's on the market today are no more efficient than CFL's, and in some cases no moere efficient than incandescent bulbs. Most also have tremendous amounts of Blue Light Pollution. and you cannot see worth darn in blue light.

To take it one step further the US Federal Government will not allow LED lights in any federal buildings. Want to know why? Because they do not meet minimum efficiency standards. That pretty much says it all. Only some CFAl and T5 and T8 Fluorescent lighting meet Federal standards.

[Steve]

So yes, Leds use 20% of the power and do not produce any heat, and they seem to last forever. The light output however is very different and I am not sure that they will be adoped in mainstream applications

Great post, thanks for making it.
I have to disagree about the heat though, at least with the higher power LED units we use. The casing of our 18w flood/spots are one big finned heatsink and get hot to the touch, as do our 7.5w spot/floods. The're not hot enough to burn-singe your hand like an incandescent but one must be careful when unscrewing them because they do get pretty hot.

I'm not any kind of "survivalist" or anything like that, but I will be contracting to build our retirement home in the Blue Ridge mountains in 10-13 years. A self sufficient underground shelter is definetly in the plan.

I think a properly done DIY solar power system would be perfect for the project. Just a couple high power white LED's for lighting, miniature LCD TV and a couple low power radios would be perfect, just as you described for your boat.

[dogsbody]

In 2004 I rebuilt my boat, and fitted LED lighting. The power output was reduced by 80% whilst the light output was about the same.
The quality of light changed more to the bluer end of the spectrum. I have to say that most was successful, except for reading where we still use a Mr16 bulb.My wife on the other hand now has a battery driven led array for reading at night. White LED "bulbs of 68 SMDs" have been tested and are about 20% brighter than 10 watt incandescent bulbs using 10 watts, and use only 2 watts. I fitted them to the boat recently. The incandecents were visable at 2.7 miles, whilst the LEds over 3 miles in the same test
In the house we have "nightlights of single 12 volt superwhite leds, driven by an old car battery with is charged by a 15 watt solar panel. these have bene in use for years, and given enough light to move around at night.
So yes, Leds use 20% of the power and do not produce any heat, and they seem to last forever. The light output however is very different and I am not sure that they will be adoped in mainstream applications