Project off-road lightbar featuring SST-90's

[TEEJ]

I misread their specs then. Oh well.



What should I be looking at?

 

[langham]

This looks really interesting I love the reflectors and the mounting system that you used. You will have plenty of spill close up, but you need the throw to be ridiculous. You can have an air tight housing with the fans inside and it will do just fine. The air moving inside will allow you to transfer more heat from the inside to the housing and to the ultimate heat sink which would be the air. I think that the cooling system would be a good idea, but might cause several issues. I think what I would do is put several fans along the length of the bar and have them all flow in the same direction, because more fans in series equals more volumetric flow which leads to more heat transfer. A better way to do what you wanted to do would have been to get a piece of copper long enough for the entire housing and solder all 13 to it. I don't think that would be very easy, but it would have done amazing things for your heat sinking issue. Every time you have a boundary between your led and the ultimate heat-sink (air) you are going to have a steep spike in your thermal transfer curve. The best thing would be to have more air flow, and something else you may want to look into is installing a CPU heat-sink like a cooler master that will cool the housing automatically, you could mount it to the backside. Keep up the good work! I look forward to hearing more from this build in the near future, the voltage changes could be solved by a car audio capacitor, they can be obtained relatively cheaply on e-bay. I could send you a 50 fared one, but that would be a LOT overkill and I don't want to think about the shipping.

 

[langham]

I know that you are very set on the SST led, and not trying to change that, but the new MKRAWT-00-0000-0D00K20E2 led from CREE does offer some interesting things with efficiency. First they are designed to run at 12.25V and only 1.25A with nearly 2000lm. Even at that kind of power they deliver in excess of 100lm/W. They are remarkable, but not the kind of power that you are talking about here, and I think that you have already ordered a majority of the SST leds and I know how expensive they are. Hope to hear more from this build soon. With 15 of these you are looking at 229W for the leds and 27000lm not as impressive, but the waist heat would be substantially more manageable. Sorry to , but after further inspection the specs for Cree were listed at 85C while Luminous was a 25C after some calculations the numbers are different. The MKR at the same specs as the SST would give you 36000lm at 229W with a lm/W rating of 156, but this isn't realistic for this application. The actuality is that I suspect they would actually outperform the SST led long term due to the lower temperatures that they would be able to operate at, (not at first) but it would not take long for the SSTs to saturate the heat-sinking and start losing lm. You would almost get 100% less power draw for this application. The SSTs do give you more lm at a serious loss of efficiency though, sorry but I had to share the information even if you know what you want.

 

[langham]

You still around? No progress for a while. Have you had time to work with it at all? This project seems pretty amazing and I am eager to see the results of all of your hard work.

 

[Diman]

Yah i'm still here not going anywere
Project's on ice...
I know, it sucks...
I'll try to pick it up when offroad season starts (which means Jeep's ready to roll and I have more "free" garage time)

 

[LEDobsession]

Hey! Updates?!

I've been thinking of doing something like this lately, too. I have free access to run CNC mills at work whenever they aren't running and when I have the time, so my mind has been scheming.... I would love to make something with the CSM or CBM-360W LED that Luminus makes as everyone is starting to use the XML. I just think that 360 is wicked cool putting out 6300 lumens, but then again the 360 is just using 4 of the dies used in the SST-90 and those things are capable of 2500 lumens with only 1 die, so I thing the SST-90 is the better option...

 

[langham]

Now that the XM-L2 is out that would be the way to go, this is an older thread and the reason he did what he did was due to what was available at the time. I would personally use a series of XM-L2 and XP-G2 emitters and de-dome a few in the center to get some serious throw. This idea is still amazing and the way he implemented his idea is great, but it was from a time when the SST-90 was at least one of the best options. The CXA arrays would be cool for one of these applications, but they require strange voltages. If nothing else this is a cool project that inspired quite a few ideas.

 

[Diman]

whoopsie there's activity here *LoL*
langham - thank for the input those CREE leds are sure very interesting! I just have set my mind on the Luminus for this project.

So i have slowly returned to this, offroad season has started and the Jeep is rolling. Have gone wheeling last weekend and on the way back this project popped back up in my head. So i've been thinking, and after a quick test I can state that i'm not going to use SST-90's . Those reflectors I've got fit precisely on the dome and leave very little space for solder on star pads.
I'm going to use CST-90's (which has been suggested earlier in the thread - I wish I had been listening - sorry )

Major advantage (besides CST's copper base and much lower thermal resistance from die to heatsink) is that the die dome is the same (so I can use that precise fit of the reflector) but electrical contacts are moved away and are much bigger.
So, I have a couple of SSR-90's GN100 W65S (SSR = SST on star) over which I won't be using.. maybe I'll make something out of them later.


Ordered a pair of CST's ..
will experiment a bit when they arrive.
I'd looooove to get my hands on a driver that can drive these near it's max current, say 12A, and be powered by my Jeep's electrical system - 11-14.5VDC
which would also remove shape/size restrictions.
So far i've found nada...
Right now I'm researching how difficult it is to make my own driver. Looking at different driver chips LM3401, MAX16820, MAX16834 and even bang-bang using a PIC mcu and MOSFETs.

 

[DIWdiver]

In case you've forgotten or somehow missed it...

http://www.candlepowerforums.com/vb...Automotive-linear-13-5A-LED-driver-adjustable

 

[Diman]

Well, look at that !!! I missed that totally Haven't been here for a while, sort of...
Very interesting !

I'm going to read the datasheet ...
Thanks DIW

 

[khrystyan27]

Interesting project!

Can't wait to see the final product.

 

[EastMtMike]

Just wondering if there has been any more progress on this build. I would like to do something similar (smaller scale) on my truck for camping and such. I am a complete novice when it comes to these things so I will be following intently. My biggest concern would be drivers. I see that LEDs are pretty picky when it comes to input voltage/spikes/etc. Any advice would be greatly appreciated!

 

[DIWdiver]

Check the link in post 129.

 

[langham]

Just wondering if there has been any more progress on this build. I would like to do something similar (smaller scale) on my truck for camping and such. I am a complete novice when it comes to these things so I will be following intently. My biggest concern would be drivers. I see that LEDs are pretty picky when it comes to input voltage/spikes/etc. Any advice would be greatly appreciated!

I will build you one, unless you just want to do it yourself. Once you have a few more posts you can PM me, or I started a thread that has "LED Light Bar" in the title.

 

[EastMtMike]

Check the link in post 129.

I tried to check that out but my AV said the file was infected???? Is there some other way to get more info?

 

[DIWdiver]

search on CPF for "automotive linear 13.5a led driver".

 

[langham]

Poke, Did you ever finish? I made one out of 4 overdriven XM-L2 leds and got around 6000lm, but I would love to see how this thing performed.