Here is an example driver. This one is rated at 30V to 38V output at 1.5A. So it would be suitable for 3 XHP70-12V connected in series. The input voltage range is 9V to 24V, so it should be able to handle the varying voltages from a car’s DC power system.
Don’t select just any DC converter. You need one that is constant-current and designed for LEDs. I gave an example in an earlier post.
Thanks dthoang, I think you’ve put me on the right track. I’m thinking of trying this one and running 2 6v XHP70 in series. It should give me the chance to try overdriving them a bit. Since its so cold here in the winter (–40 C/F, they’re the same btw), I think I should be able to get away with it.
Question: Would a module like the one mentioned above be able to put out voltage both greater than and less than the input voltage?
That’s more of what I was thinking for the driver(s). Put them in the cab and run the wiring harness. At your temps over driving a bit might not hurt but do look at the thermal paths of the Leds so they don’t cook in their little compartments. I’ve seen poorly built Chinese light bars literally insulate the Led’s with plastic holders and bases.
I’m thinking about ripping out the insides of one of those cheap lightbars and using its enclosure instead of trying to build one on my own. I think I will be able to mount the LEDs straight on the Aluminum so I think it will have a decent thermal path. Although I’m not sure if the enclosure will be deep enough to put a decent reflector into or not though…
Looks good enough. You’ll be placing 1 led in place of a square of 4. No idea of the lens or reflector to use, ideally 60-80mm. This one gives you about 2 inches of room/reflector. When stripped down look inside to see if you need to ad any metal connections from the led pad to the finned outer shell. Some of these cheap bars actually use plastic between the two making the fins non functioning or use plastic fins all together. Even in really cold weather that heat has got to get out or things start to melt or cook, like wiring, plastic mounts.
That particular item is a buck converter where the input voltage must be higher than the output voltage. You can use it to drive one 6V XHP70, but I do not recommend driving two XHP70 in series.
Follow the directions provided by the seller on setting it up. Basically set the voltage to the highest forward voltage you expect the LED to draw at the target current. Then connect the LED in series with an amp-meter and adjust the current setting.
If you want the output voltage to be able to swing higher and lower than the input voltage, get a buck-boost type converter.
Another tip is to derate the current and voltage ratings given by the seller. If it says 5A, expect 3A or less. Here is an example taken from one seller’s description.
Did you ever figure out which driver you’re going to use? I’m interested in doing the same thing but I’ve never messed with these high power LEDs before. I’ll be following this thread to check on your progress.
I actually just started a new job that is taking up a lot of my time. So I decided that I would start out by just making a modding a flashlight just to get a feeling more of a feeling for how everything would work. I just put a XHP50 in a Supfire L3. I’m pretty sure that 10 of these together would be very impressive! However I still haven’t come up with a truly acceptable housing for everything. I am thinking of using a piece of 2” or 3” square aluminum tubing, but that would require quite a bit of work with tools that I don’t have to make it work. Maybe you have some ideas on this?
I have seen posts of someone using aluminum in a U shape. I have also seen where someone using aluminum bar and glued everything together with Jb Weld and some type of thermal bonding product. My issue with doing this is that flat aluminum has no cooling fins. on one of them, they cut cooling fins and glued them to the flat bar.
There was a post on pirate 4x4 forum where the guy used some extruded aluminum to make light bars. IM trying to source empty enclosures that are purpose built for light bars.
Edit: here is a link for that 4x4 forum build
https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.pirate4x4.com/forum/general-4x4-discussion/1073515-diy-hight-powered-led-light-bar.html&ved=0CBwQFjAAahUKEwjCipGl67nIAhWMpB4KHZm8CMU&usg=AFQjCNGrDCOo0A8xkOFXEskuah-osLZ_7g&sig2=xW3fOIgeLzJtKEkg8VCtgg
You’re post got me started thinking about working on it again. I had ordered a cheapo lightbar off of amazon that I pulled apart in hopes of using its enclosure. I’ve searched high and low for just the enclosures, but all I could find were whosalers on aliexpress. In the end amazon was easier. It turns out that there is only about 3/4” of an inch between the clear plastic and the rear of the aluminum, this wouldn’t give much height for a reflector. (Maybe this one?) However I think that it might be possible to extend the edge height using angle aluminum attached with machine screws and JB weld.
Kinda like this: https://slimgr.com/image/Y5y
This would work out to allowing a reflector that is 75mm wide, (although I think that might be a bit excessive) and whatever height you want. However I’m thinking it might make more sense to use slightly smaller reflectors and more of them (10x?).
Ohhh and just to give you and idea of the brightness of these LED’s I took my light out with a single XHP50 in it and its brightness was somewhere between the low beams and the high beams of a 2014 Chevy truck. I can only imagine what 10 XHP70’s would look like!
I had the same idea with Amazon junkers. I ordered some srq2 look alikes to clamp on my handlebars. The housing is stout aluminum but electronics are junk. I’ve thought about sending cad design to a fabrication place but I don’t think that would be worth the money for a light bar.I’ve seen a few extruded heat sinks online but they look rather flimsy and have cooling fins in the wrong direction to catch the air flow right. I don’t know how much cooling that a 30watt led needs…
Cool idea about buying a cheap light bar and modifying it.
I've been thinking about doing something similar but using a light bar instead of high beams. With 55W to play with, I can easily match ~1500 lm per bulb.
My plan was to use 3 XHP70s on 12V sinkpad IIs and power them using one of these 12V Boost Drivers. 12V @ 3A is about 40W power, including the driver. Output should be about ~2000 LM per led (12V 1A). Of course I wouldn't wouldn't leave it there... 55W is a lot of power to play with.
Yeah it’s an intriguing idea but unfortunately the one I bought has no Room. https://www.amazon.com/gp/aw/d/B00GLLW3AM/ref=yo_ii_img?ie=UTF8&psc=1
The “3 watt” LEDs are complete junk. My maglight led without the reflector puts out more light than all six of the cheapies. I almost used them on my lawnmower but decided to pull them apart to look at the insides. I wonder if any of the other Chinese light bar housings would be better?
What are these like practicality wise ?
Check out these drivers from this Russian eBay store. Look like they are built well, can easily handle a few XHP LEDs per driver, cheap, and they have a PWM board to drive them with a dimmer switch which they can configure for you before they ship it. I will be using these or TaskLED drivers for my DIY LED light bar, which I will be using 6 top binned XHP50s, which honestly will be tons of light.
For example:
5–100;
50–100;
1–100;
1–70–100%;
3–40–70–100;
5–25–50–70–85–100.
Your idea of 10 XHP70’s is quite simply ridiculous, first that is too much light, second, too much power to deal with, third, there aren’t any good optics for them for automotive use, IMO… fourth, but not last is the shear amount of heat you will have to pull off that many large LEDs, you need a large enough heatsink that will keep them cool enough for reliability, you don’t want to dump a bunch of money into that many expensive LEDs and them have them burn out because they are over driven or over heat (both).
I think it’s crazy and cool, not ridiculous, but I think maybe someone is underestimating the amount of light just one of these would put out. I’m using just 3 xhp50 s with elliptical tir and I think it’s maybe overkill for my purpose. Just one of those puts out more light than 55 watt halogen I think.
One XHP-50 emits as much light as both a cars headlights combined, when properly collimated/reflected. That is, a top binned XHP-50, as they vary between 680 Lumens to 1120 Lumens @ binning conditions (700mA @ 12v setup), that is a 65% brighter.
yep, you could really light something up with 10 70’s . Take that light bar out in the hills and people would be talking about UFO landings. lol