Residential Lighting with LEDs

Dunno about led lighting, but there are guys here who do...they just aren't awake yet.
But even a cat can do his own solar hot water...
Good luck with the build, (I wish I'd had the money and time to do it years ago).
Del

thanks for the responce!

All NICEIC-registered electricians in the UK will work to British Standard 7671.

While it is perfectly possible to run a DC lighting circuit around the home, it is not done as a routine. Extra-low-voltage DC requires more conductor cross-sectional-area than an AC lighting circuit for the same overall power consumption, as the currents are higher and the voltage drops must be much lower.

Installing local proprietary lighting transformers where extra-low-voltage DC is required is the norm here. Final DC circuits end up being shorter and more local as a result.

Extra-low-voltage DC circuits are the norm in places such as caravans and river- and canal-going vessels, where mains AC is absent. Cables are much thicker in these installations, and special measures are usually put in place to prevent the inadvertent connection of AC appliances to DC circuits and vice-versa.

There are a number of textbooks on extra-low-voltage DC circuits, and the reader is best directed to, say, a high-end marine chandlery where these publications are most likely to be found.

Interesting and 'G' A (I hadn't considered it sufficiently) but I'd be interested to know if the icreased efficiency of LED lighting would obviate the need for fatter cables, (with the current price of copper...)
Not that I'm building a house or a narrow boat at the mo' _{<whistful sigh>}
Del

Under BS7671, all designs need to be assessed on their merits. There are certain "standardised" solutions, such as the 1.5mm² twin-and-earth for 5-6A lighting circuits where the cables pass through loft insulation, which makes them easier for electricians to install as they are immediately familiar with them. All these are applicable to the domestic setting in the UK where 230-240VAC mains power is supplied. A 6A domestic lighting circuit can therefore supply up to 1440W without overload, cable damage or the risk of fire.

Considering a hypothetical design: reducing the voltage to, say 12VDC as a LED supply, and doing a back-of-the-envelope estimate of the power dissipated in an LED and its current-limiting resistor of, oh, say 0.2W per LED, it seems at first glance that 28800 LEDs can be fed from a 240V, 6A, 1440W supply, easily enough to light a house large mansion. However, 1440W at 12V requires a current of 120A, which will seriously overload a 1.5mm² twin-and-earth cable. Therefore the cable size to supply all those LEDs from a single source needs to be much larger; one might be looking at 16mm² or 25mm² supply cable. Which is sort-of-why it isn't done: it is more economic to install smaller cable, supply power at a higher voltage/lower current, and drop to 12VDC with a proprietary transformer locally wherever it is needed.

ok i get most of the none tec stuff here. I understand that the wire size will dictate the amount of leds. I don't care if there are several circuts though out the house. Simalar to ac wiring . I would only be lighting the rooms used @ any one time. this would reduce the wire size? One transformer ac to dc. If i have photo electric solor panels on the roof , it comes out as dc. pritty sure it stores as dc as well. this would eliminate the use of the transforner and an inverter. I'm getting a head of my self. The led lights that are used today in a regular light sockets have a transformer built in. do they use more electricaty than going though all this other stuff? Is what I'm looking for already been achevied by the use of the exsisting led lights. Or am i on to the use of such a small differance it's not worth it. Am i saving energy? or are the raw materials going to off set all that i am tring?

Good food for thought!

<...The led lights that are used today in a regular light sockets have a transformer built in. do they use more electricaty than going though all this other stuff?...>

In order to connect an individual LED rated at 0.6VDC, 20mA to a 230VAC 50Hz supply, additional circuit components are needed.

<...Is what I'm looking for already been achevied by the use of the exsisting led lights. Or am i on to the use of such a small differance it's not worth it....>

In terms of the immediate application of over-the-counter lamp fittings to existing domestic electrical circuits, yes.

<... Am i saving energy? or are the raw materials going to off set all that i am tring?...>

The economics of high-efficacy light sources versus tungsten filament light sources cross over at the "40W-tungsten-substitute-for-10-minutes-every-day" point here at the moment, though the crossover point depends upon the rate being charged for energy locally. At £0.20GBP per kWh, the crossover point might drop to "40W-tungsten-substitute-for-7-minues-every-day", though the installation and use of heavier conductors on a 12VDC application as compared to a 1.5mm2 twin-and-earth on a 230VAC 50Hz application will confound the situation somewhat, possibly involving major redecoration after installation, which needs to be factored into the costs.

In general terms, it is better and far simper to invert the available 12VDC at the source to 230VAC, feed it into the local grid, keep the domestic wiring at 230VAC and either:

• use 230VAC-12VDC over-the-counter transformers with over-the counter 12VDC LED lamps, or
• use 230VAC over-the-counter LED lamps,or
• both of these.

If in doubt, consult a qualified electrician.

Domestic circuits are generally 115 volts AC in the states

why is there a need for larger cables. Don't leds work off low voltage. On a small scall, a head lamp will last a long time on a watch battery.

As that ole electrician, Gerald O'Hara, once said, "'Tis the current, Katie Scarlett, 'tis the current."

It is the permissible current in the circuit that determines the cable size, and not the nature of the light source load connected onto it.

On an extra-low-voltage circuit, there isn't a lot of voltage drop available for high powered loads, or clusters of low-powered loads. On the presumption that the house is to be lit by rather more than one LED, the design of the cabling system must take the expected current that however many LEDs are taking in aggregate, were they all to be turned on together. The expected current from the load needs to be used to calculate a voltage drop in the cable, which means that the cable will need to be larger for the same power than were a mains voltage used. BS7671 gives an algorithm by which it may be calculated.

LEDs operate on current. Their forward voltage drop as discrete components is usually around 0.2-0.6V, which is why a current-limiting device is required when they are connected to a power source that is higher than this voltage. All off-the-shelf AC mains lamp solutions have this current-limiting feature ready-installed for simplicity of application, which may not necessarily be the case with a one-off home extra-low-voltage circuit design like the one that is being championed in this thread. For that reason, the circuit designer must take particular care that circuit conductors are adequately-sized for the expected load, as everyday mains-based "standardised" cable solutions are not applicable.

Dunno if there is any 'standard' LED which is maybe half a dozen in series or some such, I don't s'pose they are using single individual LEDS, prob a cluster, but how big is your average cluster...?
I think a trawl around the LED lighting sites is called for.
Del

<...a trawl around the LED lighting sites is called for...>

Quite.

Philips has quite an effort put forth in LED

The forward voltage, V_F, of an LED varies depending on the LED's composition, wavelength, temperature and forward current, I_F. Here are some typical values for V_F (I_F=20 mA, T_Amb=25°C):

Infrared 1.6V

Red 1.8–2.1V

Orange 2.2V

Yellow 2.4V

Green 2.6 V

Blue 3.0–3.5 V

White 3.0–3.5V (white is produced by coating a blue LED die with a yellow-emitting Ce:YAG phosphor)

Ultraviolet 3.5V

LEDs designed for illumination purposes have typical drive currents in the 350 mA range, but with similar values for V_F as shown above.

I have a friend who's selling LED lamps that fit into existing standard fluorescent fixtures. Please send me your email address privately if you are interested so that I can help you to contact him.

Hello! Well, as some mentioned 'running' dc through the house isn't normally done. Another thing is that it depends upon where you live. As one of the previous people noted, it's seems entirely possible in the UK... I guess we're lagging here in the US lol What I've done is googled "LED Home lighting system" and came up with a bunch of options... First thing I looked at is: "Shopping results" that will give you images and possible costs of various systems. And that does not include installation! Also note that the entire system will have a MAJOR initial cost... As I noted to another person who asked about this... If you finally get to actually purchasing some, make sure you also purchase a few spares... So that at anytime in the future, if one of the LED's go out, you have 'some' on hand to replace them.

FYI:

New and much brighter LEDs are coming to maket in various configurations making their use for general lighting more efficient and economical than previously. Compare sources and specs carefully for best results in your application(s).

LED lights for homes is just now coming on the market in the USA. I have seen some offered at Costco and I do believe a few are designed to use standard 110 AC light fixtures but cannot promise this. Anyhow, I do know that there is a wide selection of dry cell battery powered LED lights that can be installed under cabinets and be used as night lights. We have switched to the low energy 13 watt lights throughout our home. One thing you can do is purchase some Lithium Ion batteries, again, available at Costco to use in your battery powered LED's. The Li Ion batteries come with a charger, so that is no problem and the battery does fit standard AA and AAA dry cell spaces as far as I can tell. Most LED lights consume less than three watts. Again, I do believe that some are designed to fit the standard 110 AC outlet. I don't know if they have an internal rectifier and voltage drop or how they are design.

I would not discourage your solar ambition's though you may find this concept interesting especially considering the Latitude of MA

http://starthere.clearedgepower.com/?s=gob+solar+light&gclid=CISm8t3-3J4CFRxJagodzG70KQ

You may find the information in these previous threads on the subject helpful:

http://cr4.globalspec.com/thread/23137/Contribute-a-simplest-led-circuit?frmtrk=CR4digest

http://cr4.globalspec.com/thread/24400/LED-lighting-for-the-green-home

http://cr4.globalspec.com/thread/12850/Solar-LED-Lighting-System

http://cr4.globalspec.com/thread/39848/LED-Lighting-in-Sequence-Using-Transistors

http://cr4.globalspec.com/thread/33547/Microchips-for-LED-Lighting

http://cr4.globalspec.com/thread/43974/LED-Lighting-Fixtures

http://cr4.globalspec.com/thread/43481/Transformer-for-LED-Lighting

http://cr4.globalspec.com/thread/24400

http://cr4.globalspec.com/thread/43974

Conversions from AC to DC and corresponding materials like cables is not very economical.

However,LEDs are not really meant for such purpose u want to use them for,but rather for indications and the likes.

Why not use Energy saver lamps that could offer u a good lighting and lesser wattage if u are not interested in the normal incandescent lamps.

Patrick Whowha

jIMO,

There are some good answers on here and, unfortunately some replies from people who have no knowledge whatsoever of the subject!

I can tell you that there are many options for low-voltage dc lighting which are suitable for kitchens, bedrooms and bathrooms. In fact, my company will be launching several ranges of such lighting products and we hope to make the selection of power supplies and connections easier for the less electrically-minded customer (choosing my words carefully). The products we plan to sell are from an Italian company called L&S Lighting and their website is at http://www.ls-light.com/en/index.aspx

Its not the easiest catalogue in the world to drive, but I suggest that you look in the "Furniture Lighting Systems" menu and in the "LED" section for ideas. As far as I know, L&S only sell through authorised distributors so there are no prices on the site.

If you need any more help, I'll be around.

Malcolm

LED's are terrific for the right applications, but at the present time, lighting an entire home is not one of those applications. About 5 years ago, an LED would provide only about 5 lumens per Watt. Now they are up to near 50, but CFL's are closer to 100 - thus about twice as efficient as an LED. The LED's would work where you want minimal illumination, they are durable, they don't produce much heat, and are small, until you add a bunch of them together to get more light. There are many, many articles available that say that LED's are not a good source for generally lighting at this time. They do however make great Christmas lights. You can put 85 strings of lights on a single residential receptacle. I have about 20 strings of LED lights out that are 15 feet long and it is going to cost me about $1 per month for the energy to run them.

Jim

Why make things difficult. New LED lights are beginning to appear that work on normal AC voltages. I live in UK where the standard voltage is 220 - 240 V AC. I recently bought a 1W LED lamp and it was suitable for the normal voltage. This gives the equivalent light to a 25 W lamp. (It is the Watts that use the energy so do not think that low voltage is the answer). The lamp I bought was fairly cheap but I could only get blue. I have since seen some white light LEDs (also for high voltage) but these are quite expensive at the moment. I am sure the price will drop in the near future. I think GE do some LED lamps for GU10 fittings (the recessed ceiling lights) at about $5 each in UK and since it is an American company I am sure they will do it for 110 V AC also - infact I think the voltage is from about 90 V to 230 V. I recently visited a Danish shop and they had a wide range of lamps - candle lamps and normal bulbs with Edison Screw and small Edison screw fittings as well as bayonet caps - all about 1 W to 3 W. These are very expensive just now US$14 each but I think that is novelty value until they become "mainstream". Try to contact GE or Phillips lamps!

Voltage and current issues are easily overcome...but at a cost. I think you can expect as much as 4 times installation cost over AC, however, you would recoup this over time.

Perhaps the bigger issue is "would it be up to building code". Make sure you check this out before you begin. Many locations have "Illumination Standards" that must be adhered to.

Good Luck!

You can buy standard screw type bulb based on LED.

For housing use CREE, North carolina makes good light engine. If you are buying LED bulb only advice I will give is to make sure the light engine is from CREE. There are few Chinese company who are trying to build the light engine but they are little behind in terms of quality

Masyood

I scanned through the thread and didn't see anything along these lines...An LED is a diode, why not use it as one? Have two strings of LEDs one the opposite polarity of the other. Enough led's in series (unless I have gone dyslexic today!) will give a sufficient voltage drop. Some current limiting through capacitance or inductance can limit the current. I have seen some designs such as this online, but I haven't crunched any numbers as to their efficiencies. You might buy a string of LED Christmas lights and dissect them to see how they are configured and use this as a model. Regardless, you can buy a lot of incandescents and energy for what super bright white LEDs cost. Another option would be compact fluorescents.

Suggest taking a long hard look at Halogen for now...LED when cost effective.

The longer the wire the less power at the other end. This is important in low power systems like the one you are talking about. Same the with the guage or thickness of wire with one important difference, the smaller the wire the higher the resistance, or friction, as the power used increases. Friction causes heat and can cause fires. I hope this is not too simplistic just want to make sure it is understood. This is important in deciding what you want to build. There are several good suggestions here but I believe what you want is best achieved by using solar panels, DC powered florecent bulbs, and drycell batteries. These bulbs are low power, bright enough for most applications and readily available. There have been alot of improvements for strorage batteries in resent years, Google will give you alot of good options. A bank of 4 or 5 of these batteries hooked up to 3 or 4 solar panels should be enough to run 4 or 5 lights around your house As long as you didn't plan on running all of them at the same time all night. Use smaller wires running from the panels to the batteries, maybe 24 guage this should be enough to carry pico voltage needed to charge the batteries all day. Use larger guage wire, 18 to 14, to run from the batteries to the lights. I wouldn't expect to run a television on this circuit but it doesn't sound like you plan to. They might have led cluster lights out there that would work but my experience is that if they are bright enough to use for practical lighting, they drain your power pretty quickly and they generate a lot of heat…stay away from halogen. My Dad and I built a simple circuit like the one I discribe in our house when I was young with just 2 batteries, 2 panels & 6 lights and it worked very well...keep a couple of backup batteries for bad weather…good luck!

THANK YOU ALL FOR THE INPUT. AFTER WEIGHING OUT ALL THE DIFFERANT OPIONS. @ THIS POINT I THINK I AM GOING TO SHELFE THE LEDS AND GO WITH WHAT IS ON THE MARKET. I DO FEEL THAT SOMETHING ON THESE LINES IS THE FUTURE. SOLAR, WIND, LOW CUNSUMTION PRODUCTS. I WASHOPING TO BE ON THE EDGE. CONSERED FOR MY KIDS FUTURE. THAT'S IF 12.21.12 DOESN'T CHANGE THINGS! THANKS AGAIN.

I have done quite a bit with LED's and am planning on doing the same thing. They sell LED light strips and arrays for just such a purpose. They come complete with drivers and all needed components (except wire). www.superbrightleds.com

I've purchased from superbrightleds.com before. I'm generally pleased with their parts, overall, but you do need to check them before putting them in a permanent installation. I suspect superbrightleds.com buys other manufacturer(s) parts that don't quite meet spec. Not defective, necessarily, but not up-to-spec.

Not long ago I bought a very large number of ultraviolet LEDs from superbrightleds.com, only to discover that the clear epoxy resin they used to mold package fluoresced bright blue. The resin both absorbed and down-converted the UV light, significantly reducing the UV content of the output. I was not pleased, but the price was so cheap that it wasn't worthwhile to send them back.