Prototype off-road/boating spotlight - King COB!

A friend of mine, who knows I’m into this stuff, asked me if I could make some kind of light that can be taken on his quad or boat at night. He has property upstate with lake rights (I haven’t seen the property myself) but he wanted something that would illuminate up ahead and have some down-range throw as well. I remembered watching videos of the Stratus LEDs guy… so I bought a 3-pack of his reflectors and LED drivers. I had a bunch of Thermaltake heatsinks which are a bit larger than his; just needed to make an adapter that would hold the LED and reflector.
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The control box was from Radio Shack, and was salvaged from another project…
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I used these Deans t-connectors because I wanted to be able to have the unit run from either the cigarette lighter socket, or a 2s-4s LiPo…
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View of the adapter… I left the CNC unattended and the endmill started to gall because the chips weren’t clearing out and getting re-cut, so the result is the crappy finish on the outer edge. Well, it’s a prototype…
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The CREE CXB3590 fits perfectly in this reflector!
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Shown with a 3sLiPo…
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Quick control pic:
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And at “holy crap”:
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I do have a pot attached, so dimming works great. It’s tough to photograph, because when I get to a certain point the light looks the same through my cell phone camera even though it’s visibly brighter.

Great build!

I have seen those drivers before and always wondered if they would work with the high power CXB emitters, since according to specs the driver is 28V max and the Vf of those CXB is well above at 36V. Do you have a way of checking if it’s really pushing 28V or higher to the LED?

They have great price considering all the possibilities for dimming and remote controlling.

Thanks! Yes cost was an issue so I went with these despite under-driving the LED a bit. I do have some TaskLED HyperBoost drivers that would work better and could also be controlled remotely but this is more plug-and-play.

Removing and installing the reflector is a chore but I can measure the voltage at the terminals on the board when I get the chance if that helps.

That is a really nice build Louie. :beer:

Thanks! Trying to figure out a lens and enclosure for the “real deal” version… 5” PVC schedule 40 would be perfect but not easy to find locally. Although I kind of like the “bare” look in a steampunk kind of way…

Here’s a pic of the parking lot at work around 5:30AM… At the center about 275ft away is a house dimly lit…
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And with the light on at about 90%
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I just picked up a CXB3590 to play with and possibly stuff inside of a US Navy battle lantern. I clamped it to an old Dell heat pipe based heatsink and it barely even seems to get warm though I won’t have room for the heatsink inside the battle lantern.

I suspect I’ll have to machine my own reflector as the Stratus LED unit is far too big.

The other day, I was actually playing with the idea of trying to build a triple using these crazy LEDs.

I have to eventually get a proper driver for this; the Stratus LED driver is rated for 3.5A at 28V, so when I connect a 3s LiPo to the driver, I cannot turn the dimmer pot all the way. No problems with a 2s LiPo, but the output is not as bright. I have a driver for this that works off 110VAC that I will incorporate into a nice outdoor flood light for the house. The Stratus LED parabolic reflector’s LED aperture fits exactly over the 3590 ’s LES which is nice, and as far as I can tell looks like it’s perfectly focused.

I also have some nicer COBs, Cree CMA3090 that are CRI90… but they run at 3.6A at 48V. Trying to dissipate 172W of heat will be fun…

I’m actually curious just how much heat they actually need to dissipate. It can’t be the full input power since some of that is being converted to light.

I modified my mount and added some heatsink compound and then ran the CXB3590 at the maximum that my bench psu will do which is ~36v and 2.0A. Anyway, with the Dell heatsink, it definitely needs some airflow so I tossed an old 80mm computer fan running at just 5v near it and the temperature stabilized and started dropping.

Are you sure the output of the Stratus driver is only 28v? It claims to be a boost driver and maximum input voltage is 28v but I can’t find anything that says what the output is besides 3.5A max.

For what it’s worth, this is the variant of CXB3590 I got.

https://www.arrow.com/en/products/cxb3590-0000-000n0hcd50g/cree

5000k and 80cri seemed like the best compromise of those that can actually be purchased. The CMA3090 series looks to be a bit smaller, less efficient and there is no option for 5000k in the 90cri.

I e-mailed Stratus LED about modifying their driver for a higher output voltage. Looks like the COBs they use are nominally 24v so, 28v would be plenty for them. However, they claim their driver can not be modified for a higher output voltage.

For efficiency, it looks like your average modern LED is able to convert anywhere from 20% to 25% of input power to light so you need to dissipate 75% to 80% of the input power as heat. I actually thought this number would be higher but it seems the maximum theoretical efficiency for a LED is somewhere around 40% so we might see 250lumen/watt some day.

Well, I was looking for something a little smaller than the 3590. And I had a typo, it was CRI80 (at 4000K). Not really too worried about efficiency

They do have 5000K CRI90, you just have to buy it in multiples of 1000!

True, but I try to figure in a bit of overhead, as I may be operating these in the hot and humid summer months here in NY.

The AC-DC driver I have is a MeanWell HBG-160-48B

As to the Stratus LED driver - I’m trying to remember where I saw that, or maybe I mistook input voltage… Don’t remember? Might have to test it with the 3090s…

Hrmm. I didn’t see a 5000k 90cri in the datasheet.

This looks like the Dell heat sink I’m using…

I actually have two of them that I pulled out of some old Pentium4? machines. I don’t know what the lower plate is made from but it feels like some really soft aluminum alloy as it is pretty easy to bend.

I may try to find a smaller heat pipe based heatsink but this Dell unit is actually kind of nice since the fins are fairly thick and so they’re not sharp.

Have them in 2-step, 3-step, and 4-step… and you only need to buy 50, not 1000! Group buy? :money_mouth_face:

Off a server, may have been Xeon chips… Looks like a nice heatsink. I wish I saved all the ones I had; threw them out when I moved; used to rebuild and repurpose PCs for friends and family.

I just used the cheapest Thermaltake heatsink, then went into my pile of Mic-6 drop-offs and milled an adapter plate; it has a recess for the 3590, and I used MX-4 thermal compound. It’s almost as if the Stratus LED reflector was made for the 3590 as it fits perfectly; though there’s very little room for the solder joints.

I spent some time last night collecting data and parsing the datasheet for the CXB3590 and noticed some interesting things.

This LED is extremely efficient around 30w. It hits around 190lm/w and produces ~6000lm.

As input power increases the efficiency falls off but even at 12000lm, it’s still operating around 170lm/w

I did some research on DB Custom’s modded Fireflies E07, and he’s hitting 10000lm at something like 100w input and of course, this is only for a few seconds as the whole thing overheats and the cell starts crying for mercy.

I seriously think that we could build something like a Convoy L2 with 2s or 3s 26650s and maybe more heat sinking on the head that could do 10000lumens fairly sustainably. It would require a custom driver though as I don’t think the hyperboost can handle the input current that this would require.

Have you looked at the LEDiL Stella lineup? Thought of doing something like this myself and I figured, with such a large heat sink, that cutting the size of the reflector down would be good thing. You would also gain some level of waterproofing and be able to switch lens according to you needs.

https://led.cdiweb.com/datasheets/ledil/15186-Ledil-datasheet.pdf

https://led.cdiweb.com/products/detail/FN15186STELLAHB-LEDiL/602330/pid=468

https://www.mouser.com/ProductDetail/Ledil/FN15186_STELLA-HB

I saw the LEDiL Stella mentioned in the optics thread. The model above looks pretty good for my purposes. 90mm is kind of huge but I guess it is what it is…

If Arrow had it, I’d buy it right now. Gotta love that free overnight shipping.

I only just realized the CXB3590 is ~50mm diagonal.

The hyperboost is good up to 7A max input I believe. But you’d need to find a way to shoehorn it into an L2 host. Methinks one of the 4s soda can lights, along with LEDIL optics, would make for a pretty cool host

The 6A~7A input current limit means that you’d need a minimum of 5s to get close to full output. This isn’t really a problem for my Navy Battle lantern retrofit project but for a “hand cannon” it probably is…

A soda can light would have a very hard time dissipating the ~100w of heat. I had a similar idea but put a big heatsink and fan between the LED and the batteries.