# Making custom 12 Volt LED Lighting



## unlisted (Apr 28, 2008)

Long time lurker, first time poster. Just never had anything to say really.

I'm looking at retrofitting my RV and parts of my home to LED lighting for a few reasons. 

1. Power at my residence is not always reliable, and I want to have a low voltage backup solution.

2. LED lighting does not attract insects, and oh boy, do I have allot where I camp and live. 

3. It (LED's) use power very efficiently. I like that. 

So basically I am looking for a supplier of allot of LED's- at a very good price. I have briefly looked around this forum and could not find the info I wanted, hence this posting.

I've been cruising ebay for about a month now, but do not know how reliable those LED's really are. (or which ones would ideally suit me) I am also looking to buy in bulk.. Ideally 100 to start (as sample/testing) and than another 500- 1500 thereafter. I'm wanting individual LED's- (nothing complete) no 110 volt complete bulbs- as they are rather expensive. 

Oh, also ideally wanting a LED with a wide beam spread. 

Any info, suggestions would be great, Thanks.


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## HKJ (Apr 28, 2008)

unlisted said:


> 3. It (LED's) use power very efficiently. I like that.



But your need a resistor in series with the led and it will reduce the efficiency.
Your can also use a switch mode driver board, it may keep the efficiency in the 80-90% range.

The best way to make led lightning would probably be getting some switch mode driver board with 12 volt input and X volt output, then build chains of leds to match the drivers output voltage.


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## unlisted (Apr 28, 2008)

HKJ said:


> *But your need a resistor in series with the led and it will reduce the efficiency.*
> Your can also use a switch mode driver board, it may keep the efficiency in the 80-90% range.
> 
> The best way to make led lightning would probably be getting some switch mode driver board with 12 volt input and X volt output, then build chains of leds to match the drivers output voltage.



How much will it reduce the efficiency? And what exactly is a switch mode driver board? (is that like a transformer?)


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## HKJ (Apr 28, 2008)

unlisted said:


> How much will it reduce the efficiency? And what exactly is a switch mode driver board? (is that like a transformer?)



How much efficiency your loose with a resistor, depends on the actual configuration, I can not give answer here, only an example:
Suppose a 12 volt supply and your uses 3 leds with 3.6 volt each and requiring 1A each.
Your would then need a resistor to drop: 12-3.6*3 -> 1.2 volt at 1A.
i.e. your would get 3.6*3*1 -> 10.8 watt for leds and 1.2 1.2 watt for the resistor.
This is a very good configuration with good efficiency, but requires that your 12 volt supply is stable (i.e. a stabilized supply)!

A switch mode driver is a bit like a transformer, but does not have a fixed output voltage, instead it has a fixed output current. 
Your can get these drives from http://www.dealextreme.com and other places.


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## McGizmo (Apr 28, 2008)

When you get down to the brass tacks here, consider the fact that your 12V systems are probably not 12V but likely higher. That can make a difference in your efficiencies and strategies. There are a number of different type drivers and if you want to do this right, you will need to get an understanding of how these drivers differ and to some extent, how they work. There are linear, buck and boost drivers and depending on the LED's you use, how you string them and the nature of your 12V system you may identify needs or uses for all of these. The other thing that you might consider is the fact that LED's become more efficient when you underdrive them and this means that you may elect to underdrive them or better yet, use some form of dimming or level control where you can adjust the current to the LED and enjoy greater efficiencies as well as less power draw with lower light when appropriate.

I think your plans have merit but not without some effort and a learning curve ahead for you. :thumbsup:


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## unlisted (Apr 28, 2008)

Is there any n00b study guides which I can start with?


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## HKJ (Apr 28, 2008)

unlisted said:


> Is there any n00b study guides which I can start with?



I do not know of any, but go on a shopping spree on DX and get some leds (in star configuration), some drives and a voltmeter (or two). Your will also need a power supply.
Then start experimenting and expect a few blowups.

Your can ask here about your problems and your will probably learn a lot about working with leds.


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## unlisted (Apr 28, 2008)

Do you have a web link to the place you mentioned above?


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## HKJ (Apr 28, 2008)

unlisted said:


> Do you have a web link to the place you mentioned above?



http://www.dealextreme.com/

They have a lot of cheap junk, what is perfect for experiments.
They also have some of the better stuff.
If your search cpf your will find many references to DX, look for sku and a number, that is very often from DX.

edit:
Another website that is very usefull for this kind of "junk" is:
http://www.kaidomain.com/


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## spun (Apr 28, 2008)

and this driver as well:
http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982
you'll need good soldering skills to attach the wires and it can take months for these to arrive. some people also caution that automotive voltages can spike higher than the 18v max of this driver under certain conditions.


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## McGizmo (Apr 28, 2008)

Although these drivers are still vapor at the moment, you might want to look at Wayne's latest efforts, HERE. 

I question the comment about automotive voltages spiking above 18V?!?! I have seen _12V _wall warts that spike above 18V but most automotive systems stay below 15V to my knowledge else significant damage can result?!?! :thinking: :shrug:


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## filibuster (Apr 28, 2008)

If you don't want to hassle with making your own, here are some ready made 12 volt LED lighting options from DX that may be suitable to your needs in an RV.

This is a 30 LED light strip that is 12 volt ready.
http://www.dealextreme.com/details.dx/sku.5256~r.13686786

It has good brightness and only a tinge of bluishness to it and you can get three of them for just over $25 bucks if bought in bulk.

A similar one comes in a 75 LED strip too:
http://www.dealextreme.com/details.dx/sku.11303~r.13686786


Another option I've tried is this 12 LED array that can be retrofitted into some fixtures:
http://www.dealextreme.com/details.dx/sku.3513~r.13686786

This same style array also comes in 8, 16, 18 and 28 LED clustered arrays
http://www.dealextreme.com/products.dx/category.708~r.13686786


Here's an LED rope I'd like to try:
http://www.dealextreme.com/details.dx/sku.7561~r.13686786


These also look interesting for making LED fixtures:
http://www.dealextreme.com/details.dx/sku.5752~r.13686786

http://www.dealextreme.com/details.dx/sku.8530~r.13686786


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## unlisted (Apr 28, 2008)

I just wish that DX place would ship to Canada for a good price... 

Are any of those ebay ads good? and if so, can anyone recommend any? (or does anyone on here have allot of led's and would not mind selling some to me?)


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## Calina (Apr 28, 2008)

unlisted said:


> I just wish that DX place would ship to Canada for a good price...


 
DX's shipping is free.


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## knabsol (Apr 29, 2008)

I would suggest that you go into the "Fixed lighting" subforum and check out VanIsleDSM solution, he has done great work and it sounds like you´re trying to do something in that way, so hear with him and maybe you can learn from his experience.


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## R290 (Apr 29, 2008)

Good thread with good links. I too am looking to run LED on a 12volts ( My car battery measures more like 13v with the engine off and my 130 amp alternator measures 14.2v at the output ) When camping it would be great to have the leds on the dimmer too. This way I could run them full bright and them dim as needed to conserve power. 

Anybody got a link to the driver that's in stock and has a dimmer feature too. I would like to find something that could go as high as 1amp and drive several LED's. Or even a nice fixed unit around 750ma would work too.

I just bought some P4's http://www.dealextreme.com/details.dx/sku.2134 as they are cheap enough and should provide enough lighting. I will make my own heat sinks, just looking for something to drive these:candle:

have not found Vans driver yet, but found this post for home stuff
https://www.candlepowerforums.com/threads/183477


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## McGizmo (Apr 29, 2008)

R290,

You are a man after my own heart. THIS fixture here is one I had made and it is host to a really cool driver Wayne designed. If you look at the fixture, you will notice it has a third wire (white). This is a signal wire which doesn't need to be used but if it is connected to a dimmer circuit that Wayne designed, it receives a signal which over rides the set 350 mA and allows you to dim down to zero mA. Any of these light fixtures connected to the same dimmer control via the signal wire will respond in uniformity to that particular controller. It's a really cool system and circuit design that never got flushed out completely. The same system could work on a single driver which powered up a string of LED's and was managed by a central dimmer control.

The technology is there and it's just a matter of someone funding the ideas and bringing them to market. In the mean time, it is quite frustrating for those of us who realize the potential but can't bring it about ourselves.


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## Mr_Light (Apr 29, 2008)

If driving four leds in series direct off 12V is not under driving them too much for your taste, you could try that with a variable resistor inline as a dimmer. You could always try this setup on the bench to see if it is bright enough.


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## LukeA (Apr 29, 2008)

It's not that LED light doesn't attract insects, it's that _dim_ light doesn't attract insects. You should see my LED spotlight in summer.


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## filibuster (Apr 30, 2008)

R290 said:


> ...Or even a nice fixed unit around 750ma would work too.



Here is a circuit that I believe fits the 750ma bill. This board is from kaidomain and has a 4v-18v input with a 755ma output (*SKU2982 KENNAN)*:
http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982


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## matrixshaman (Apr 30, 2008)

One other thing to note I don't believe I've seen stated here. Your typical 5mm LED's and the like still mostly have a bluish tint to them compared to the high power LED's like Luxeon III's, V's, Rebels, and Cree's. All the high power LED's can be had in very white bin colors that range from a slightly yellow (closer to incandescent) to slightly bluish to very white. I'd suggest you consider these over 5mm LED's. A couple years ago I bought a 120 volt 18 LED light bulb replacement. It was very bluish - made of 5mm LED's and output was less than a single Cree LED.


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