1" diameter - 12volts DC- 400 lumens direct drive possible?

[lightime]

My first post so... Hi all!!!

I want to apologize in advance if this is a ridiculous question :cool:

Ok, so I am VERY confused. I have just recently gotten into led's and at first I was looking at "normal" led's (the ones that cost a few cents and can be wired straight to a 12 volt DC car battery by using a tiny resistor)....then I found the SSC-P7 and CREE MC-E etc...these seem to be a little more complicated to wire straight to a 12 volt car battery but seem to be MUCH brighter.

I have 1" diameter to play with and about .5" depth and I want to acheive about 300-400 lumens without needing any kind of power supply, driver etc...to hook up to a 12 DC volt car battery. Is this possible at all?

I thought about doing 8 or so normal led's with resistors but I'm not sure if I can reach that lumens target. Again I am confined to a 1" diameter, .5" depth, and 12 volt DC system. What are my options?

PS. I do not want to be able to control brightness, strobing or anything like that just straight on or off.

 

[lightime]

Most simple way to hook up a SSC-P7 in a car...

I am new to led's so please bare with me. What is the simplest way to hook up a single SSC-P7 in a car (12 volt dc, fluctuates between about 12 volt and 13.5 volt when running )? I only want to be able to switch it on and off and achieve max reliable brightness.

Thanks in advance for any help.

 

[mds82]

Re: Most simple way to hook up a SSC-P7 in a car...

you need to purchase a constant currant power supply. this will help regulate the power from whatever input to the correct voltage and amperage for the LED.

 

[DM51]

Re: Most simple way to hook up a SSC-P7 in a car...

Welcome to CPF, lightime.

I'm merging your 2 threads as they are closely related.

 

[lightime]

Thanks for the replies. Where can I get a power supply for hooking up the SSC-P7 in a car where the voltage will vary from about 12 volts to 13.5 volts?

Will a single P7 be brighter than say 10 normal led's wired together? Is it possible to reach 400 lumens with around 10 standard leds wired together?

Thanks

 

[Wiggle]

The "normal" LEDs you talk about are probably not even within an order of magnitude to the P7/MC-E output wise.

 

[blasterman]

First, you'll need a driver to regulate the variable car voltage. No big deal.

However, you'll need a way to handle the heat any 400 lumen emitter (P7, Bridgelux, MC-E etc.) will generate.

 

[lightime]

Can I use this: http://www.dealextreme.com/details.dx/sku.26110 (18V 5W Cree Circuit Board for Flashlights) to power a P7 with 12 volts input? If yes, how much power would a P7 plus sku26110 draw when on?

Or is this better:

http://www.dealextreme.com/details.dx/sku.13557 ... if so why?

Thanks

 

[blasterman]

I don't believe either supply near enough sufficient current to run a P7.

 

[Marduke]

It may be simplier to direct drive 3 or 4 XR-E's on a largish heatsink.

 

[lightime]

Blasterman, if you read the reviews on the page of sku13557 http://www.dealextreme.com/details.dx/sku.13557

It says it puts out 650mA. What kind of lumen would that produce with a P7, what about a Cree XRE Q5?

How efficient would one of those drivers be?

Thanks!!

 

[lightime]

Marduke, thanks for the reply...I want to use only 1 single LED. Thanks!!

It may be simplier to direct drive 3 or 4 XR-E's on a largish heatsink.

 

[Marduke]

Define single LED...

The P7 is a multi-die emitter. Using a single die LED, it is practically impossible to get anywhere near your target brightness.

Since you considered 10x5mm's, I figured several highpower would not be an issue.

 

[lightime]

Sorry, I am new to all this. I meant a single P7, Q5 etc...:cool:

At this point I think I am just looking for the most efficient ways to power say a 650ma to 1000ma single multi-die with a 12-14 volt DC input.

I think the most efficient is the "buckpuck" but it is expensive... I'm not sure how it compares to the sku13557 from dx as far as efficiency? is there anything as efficient as the buckpuck for less $$?

Define single LED...

The P7 is a multi-die emitter. Using a single die LED, it is practically impossible to get anywhere near your target brightness.

 

[Marduke]

The most efficient would be 4x XR-E's direct drive without even a resistor. An MC-E prewired for series would essentially do the same in a more compact package.

It might help if you actually explained your circumstances.

 

[lightime]

Basically I am limited to a max 1" diameter lens to place the led itself so I can't use more than one. I am trying the get the most light while staying with this diameter and 1000mA or less. This will be installed inside a car in a rack that holds some audio equipment so that is why I need to use about 12-14 volt input.

Thanks again for all your input.

 

[Marduke]

Well, your heatsinking is extremely limited in that space, so continued operation is not possible at full output.

4x XR-E's would fit space wise, but for any setup you need to go thicker for heatsinking.

12W of power is a lot of heat to dissipate.

 

[lightime]

How thick would the heatsink have to be? what type of plate could I mount the 4 XR-E's to? Do I still need some type of driver or how do I wire them?

Thank you again.

Well, your heatsinking is extremely limited in that space, so continued operation is not possible at full output.

4x XR-E's would fit space wise, but for any setup you need to go thicker for heatsinking.

12W of power is a lot of heat to dissipate.

 

[Marduke]

How thick would depend on how long you will be running the setup, and if any other cooling is present. LED's are like computer chips, heat will destroy them and you need cooling.

Either 4x XR-E's or one MC-E would be wired in a series configuration. No driver required, and you can possibly get away without using a resistor.

You could also use 3x XR-E's and a drop resistor.

 

[bshanahan14rulz]

:poke:direct drive, provided you have a non-automotive 12v source. if automotive, please use voltage regulator. automotive 12v is dirty.