High Power LED's

Hope this is in the right section.

I've been looking into the idea of building my own led auxuillary lighting for my truck. After reading a bit on the cree's and P7's and reading LEDobsession's build (https://www.candlepowerforums.com/threads/213704) I had my motivation.

However, I came across these: http://www.lck-led.com/p516/ZxPower-K30-30W-COB-High-Power-Led---Typ.-1800LM,-12v/product_info.html



Is there any reason why I couldn't use these instead of using a series of P7's that is equivalent to the lumens as the above single unit.

Thoughts, comments please...

Thanks!

Mike

It's a 12 watt light with more output than your typical house lamp. Do you want that much light in a small space?

Other than that, I see no problem with using that led.

Daniel

I did a little bit of maths and using the worst case numbers....

1600 lumen / (1.5 A * 12.5) = 85.33 lumens / watt.

Are those figures believable, given that in typical use a P7 won't acheive such good efficiency?

Since the rebel 100 hits 100 lumens per watt I'd say 89 is quite possible.

Daniel

gadget_lover said:

Since the rebel 100 hits 100 lumens per watt I'd say 89 is quite possible.

Daniel

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The 100 lumen per watt figure that the rebel acheives is not a full power figure, that's its 350ma figure and at full drive (1000ma) they're not that efficient, the same is true of the P7 and the MC-E.

A P7 or MC-E uses about 12 watts and produces perhaps 500 lumens, thats only 41.66 lumens / watt. If a P7 or MC-E was as efficient as 85 lumens / watt, it would be producing over 1000 lumens....

I believe the MC-E/P7 is rated at 900 lumens at 2800mA. It still achieves <80 lumens/watt at full power.

gadget_lover said:

It's a 12 watt light with more output than your typical house lamp. Do you want that much light in a small space?

Other than that, I see no problem with using that led.

Daniel

Click to expand...

Specs shows the unit is 30W.

The use isn't for inside the cab, it's to light the road ahead. Similar to the one LEDobsession fabbed and put together. I thinking of using 2-4 of these, instead of 10-12+ P7's. I may get one for now and see what the end result is.

Some things to think about since I work with Bridgelux emitters in about the same power range:

Emitter arrays this size require significant heat sinks. Think 3-4x the size a of a decent computer CPU. Or, some pretty ambitious active cooling.

You still need power regulation on the front end. Either a stable source of 10 - 10.5 volts or an amp. With these big arrays I've learned to shoot for the low side of their rated voltage, so it will be easier to just get a regulated 1amp driver that can handle autmotive environments. Running it 12 volts or more will likely kill it in short order unless you have an absurd amount of heatsinking.

The one big advantage to using a lot of smaller emitters is optics. Big array type emitters like this and the Bridgelux I use pretty much have no optic options unless you fab them yourself. Pointed straight ahead it will be throwing almost 1/2 of it's light up in the air. Which means you'll have to point it down quite a bit to make use of the full light spread. Actually, that has some practical applications. However, P7s, MC-E have more optic options while XP/XR/Rebel have even more and can be easily and cheaply knocked down to 30-60 degree spreads.

Just some things to think about.

blasterman said:

Some things to think about since I work with Bridgelux emitters in about the same power range:

Emitter arrays this size require significant heat sinks. Think 3-4x the size a of a decent computer CPU. Or, some pretty ambitious active cooling.

You still need power regulation on the front end. Either a stable source of 10 - 10.5 volts or an amp. With these big arrays I've learned to shoot for the low side of their rated voltage, so it will be easier to just get a regulated 1amp driver that can handle autmotive environments. Running it 12 volts or more will likely kill it in short order unless you have an absurd amount of heatsinking.

The one big advantage to using a lot of smaller emitters is optics. Big array type emitters like this and the Bridgelux I use pretty much have no optic options unless you fab them yourself. Pointed straight ahead it will be throwing almost 1/2 of it's light up in the air. Which means you'll have to point it down quite a bit to make use of the full light spread. Actually, that has some practical applications. However, P7s, MC-E have more optic options while XP/XR/Rebel have even more and can be easily and cheaply knocked down to 30-60 degree spreads.

Just some things to think about.

Click to expand...

Thanks for the info! I actually thought about this and had in mind to use existing reflectors from some Hella lights I already have.

dyogim said:

Specs shows the unit is 30W.

The use isn't for inside the cab, it's to light the road ahead. Similar to the one LEDobsession fabbed and put together. I thinking of using 2-4 of these, instead of 10-12+ P7's. I may get one for now and see what the end result is.

Click to expand...

The title shows it as being a 30W LED, however, max current quoted is 1500ma and max quoted voltage is 12.5v, multiplying one by the other should give a figure for power, however it comes up as 18.75W.

If we assume that the LED is using 30Watts to produce 1600 lumens, we get a more believable figure for 54 lumens / watt. Using the 2100 lumen figure, would give a 70 lumen/watt efficiency figure.

Typical car headlights are between 1500 (tungsten halogen) and 3000 (HID) lumens, so this would be the right amount of light for a car headlight.

I believe this LED has been questioned before on this forum. It is just a few Crees behind a dome on a custom board. If I were you, I would use an SST-50 driven by 2 kaidomain drivers for about 5.3A. These drivers will take the abuse of dirty automotive power and the SST-50 puts out a good beam with minimal optics. I'll actually be posting some shots within the next couple weeks of two P7 driving/auxilary lights vs a pair of SST-50 driving lights. Here is what 2 P7's look like.

High beams


Two P7's in 27mm reflectors.

My ultimate goal is to mimick LEDobsession's build with the same results or better. I'm wondering if I can use 3-4 HP LED's and gain the same light output.

So do you want a flood, like the one Ledobsession built, or more of a directed beam? If you want a flood like the one pictured above, just use a pair of Bridgelux C2000's at 3,000 lumens each. If you want less LEDs and equal lumens, I would use the SST-90. Remember that P7's are known to actually put out around 600-700 lumens, not 900.

clint357 said:

So do you want a flood, like the one Ledobsession built, or more of a directed beam? If you want a flood like the one pictured above, just use a pair of Bridgelux C2000's at 3,000 lumens each. If you want less LEDs and equal lumens, I would use the SST-90. Remember that P7's are known to actually put out around 600-700 lumens, not 900.

Click to expand...

Definitely, flood. Thanks for the info and suggestion!!!!!

Typical car headlights are between 1500 (tungsten halogen)

Click to expand...

Not trying to pick on you, but I'm curious why anything dealing with performance automotive lighting gets a magical 3x-4x factor when dealing with basic physical laws?

I'd like somebody to explain to me why a $12.00, 120volt household MR-16 Halogen puts out a third the lumens as halogens at the same wattage for automotive use? Somebody is obviously full of it on the marketing side, and I don't think it's the MR-16 makers. In reality a 55watt 12volt halogen bulb only puts out what...600-700 lumens at best? Or, maybe I need a special wiring harness, a D- in 7th grade science, a European car and spinning hubcaps to get the extra lumens

Again, the biggest problem here is optics. The big arrays like the Bridgelux just don't seem to work in conventional optical housings, but go ahead and try. My solution has theoretically been to use a lenticular array to get a nice horizontal spread because you are dealing with a planar light source, and this solves the specular intensity problem. If you just want a wide flood, then by all means try em' on a big old heatsink. I'd also stick to neutral white because you'll get better driving light.

Also be warned that if you use these on the street you'll likely get a big ticket. The big emitter arrays have greater surface brightness than HID and without a diffuser they'll cause chaos with oncoming drivers.

blasterman said:

Also be warned that if you use these on the street you'll likely get a big ticket. The big emitter arrays have greater surface brightness than HID and without a diffuser they'll cause chaos with oncoming drivers.

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I definitely do not plan on using this on the road if there are any oncoming/upcoming traffic.

It'll be only used when necessary. On dark roads/hwys that are not well lit or not at all, on the fireroads/trails at night, etc.

I have a pair of Hella 700's with an HID kit (not the expensive ones) that I use as needed but, it's a pencil beam pattern. I've had a couple of fog (wide) beam patterns but, have not been happy with any of them.

blasterman said:

Not trying to pick on you, but I'm curious why anything dealing with performance automotive lighting gets a magical 3x-4x factor when dealing with basic physical laws?

I'd like somebody to explain to me why a $12.00, 120volt household MR-16 Halogen puts out a third the lumens as halogens at the same wattage for automotive use? Somebody is obviously full of it on the marketing side, and I don't think it's the MR-16 makers. In reality a 55watt 12volt halogen bulb only puts out what...600-700 lumens at best? Or, maybe I need a special wiring harness, a D- in 7th grade science, a European car and spinning hubcaps to get the extra lumens

Again, the biggest problem here is optics. The big arrays like the Bridgelux just don't seem to work in conventional optical housings, but go ahead and try. My solution has theoretically been to use a lenticular array to get a nice horizontal spread because you are dealing with a planar light source, and this solves the specular intensity problem. If you just want a wide flood, then by all means try em' on a big old heatsink. I'd also stick to neutral white because you'll get better driving light.

Also be warned that if you use these on the street you'll likely get a big ticket. The big emitter arrays have greater surface brightness than HID and without a diffuser they'll cause chaos with oncoming drivers.

Click to expand...

Exactly, making a flood light is easy and not efficient. The only time that a flood is usefull is when you are in extreme terrain where you want to see the top of a hill in front of you or the bottom of a valley. For most applications it's just wasted light. If you want to one up the P7's then use the SST-50 or SST-90 and use a few of them. This way you also have the option to set a couple up as flood and a few up as spot to give you a good lighted area.

blasterman said:

maybe I need a special wiring harness, a D- in 7th grade science, a European car and spinning hubcaps to get the extra lumens

Click to expand...

Well, depending on the wiring your car is using now, perhaps a resistance-lowering wiring harness will help you. What kind of car do you have? The Spinners generally only add a few mV, so I wouldn't even bother with those.

blasterman said:

Again, the biggest problem here is optics.

Click to expand...

Ain't that the truth! I gotta think that it would be way more efficient if they could make headlights just put out a flood pattern, but as it is, they must put out a specific pattern, with light distributed a certain way, etc.etc.etc.

As for lumens for standard halogen bulbs, not a clue. I bet MR16 are more efficient than a car halogen system when you include possibly skimpy wiring, and the optics required for proper beam pattern.

A guy on here is making a driver for the SST-90 that runs best at 12v input. https://www.candlepowerforums.com/threads/252095 I would love to see four of these things with a 50mm MC-E reflector and perhaps a couple of them with the matching 50mm DX aspheric or auro beam aspheric.