Nissan Frontier Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 · (Edited)
I dub thee: El Jefe.
It is the boss is because it starts out cold at 270 watts, then when it warms up, it stays at 270 watts. Indefinitely. Even if it is 100F degrees outside. Even if the car is not moving. This is much more power than "high-end" light bars can sustain. They start out strong, then back the power down after a few minutes to avoid over-heating.

Before I even started construction I designed a thermal management circuit, but then the idea of tapering off the power as it warms up seems to miss the point. HIDs don't taper off, incandescents don't taper off, why can't LEDs maintain full power indefinitely too? The answer is: they can, with enormous heat sinks made from time, money and pain. El Jefe has only one mode: 34,000 lumens ON.

Below are before and after photos all taken at ISO 100, f8, 1 sec shutter. Afterward I raised the black level (identically across all photos) to approximate the real life visibility. Stock high beams are the reference.


Shot 1 Standing on the roof rack to try to capture the field of view.
How sharp is the curve ahead? Spotlights don't help with that question. A spot would be pointed off the trail 80% of the time. The lenses have an elliptical pattern, basically a spot vertically but a flood horizontally, 13 degrees by 46 degrees. The extremely wide field of view is a little surreal - the visible area is much wider than the windshield, and your peripheral vision is seeing things through the side windows, similar to daytime. Driving is eerie in that the lighting doesn't move as the steering wheel is turned, it’s everywhere. It's fantastic.
I'm going to tilt it up 1-2 degrees to put a little less light on the ground in front.


Shot 2 Normally, having an LED light bar with a white hood is like a pig farmer wearing a white suit to work.
Have you noticed the trend of Jeeps and trucks painting their hoods black? It's because the spill on their hoods is blinding (if they actually drive off road). Since El Jefe is for function not street bling I mounted it back from the windshield to let the roof shield the hood instead - just like the old days when pickups mounted their lights behind the cab.


Shot 3 The only light on the hood is reflection from the rock.



Shot 4 Is this trail veering west? No it's continuing south. The wide beam makes it much easier to find landmarks and turnoffs. This light was designed for my driving needs: following twisty desert trails at 30 mph on Friday night looking for the camp site because I'm already late.


Shot 5 - Entrance to Wall Street Canyon


Just a few of the prototypes and test pieces. My priority was to make the frame as thin as possible then cram as much power as possible into that frame. I wanted 1 inch high but had to go to 1.25 inches because of the size of the lenses.


Testing the Carclo elliptical lenses. Typical parabolic reflectors waste roughly half the light as spill, which only glares off the hood, saturates the ground 10 feet in front of the car, or goes off into space.


Three LED version of final design. I made the frame extra deep to block most of the spill from going into the sunroof.


Heat testing
Before this project I thought LEDs didn’t make heat. Ha.
The Cree XP-G3 makes more lumens per watt than any other LED I could find, calculating out to 19% efficiency. Even so, at 6 watts each x 45 LEDs = 270 watts total, 220 watts are being turned into heat and the LEDs will be damaged if they get too hot. With normal horizontal fins, air can only skim the outside surface of the fins. Turning the fins vertically improves convection cooling by allowing fresh air to pass the entire the surface area. I thought this orientation would allow for a compact heat sink but I was reaching 160F in testing and had to go to this absurdly large heat sink to maintain full power continuously. Now I know why the high end light bars brag about thermal management - their heat sinks are not large enough for continuous operation so thermal management is needed to back off power as they warm up.
In this test it leveled out at 137F in 70F ambient with no airflow. I painted the fins black and did another test with virtually identical results. Projecting these numbers to 100F ambient, it should peak at 167F. With the thermal losses between the LED, circuit board, frame and heat sink the LED chip should be very close to the maximum recommended operating temperature of 85C (185F). I designed a thermal management circuit, but ran out of time to incorporate it, so I’d better not leave the light on, parked, with no wind in 105F weather.


From heatsinkusa.com


Sliced up with a miter saw and non-ferrous blade


The accuracy and finish from the miter saw was pretty good but not good enough so I fly cut to final dimension and finish. I didn’t know what a fly cutter was until I needed one, then I had to learn how to make it and learn how to use it. I'm an electronic engineer and I thought I was starting an electronic project but 90% of the time and difficulty was in machining. Great learning experience though.


How not to turn rectangular tube into rectangular channel. The non-ferrous blade in the table saw made a beautiful cut but it was risky. Should have used a band saw and file.


Lacking a large enough mill, and not wanting to outsource anything, I made a jig to drill the holes consistently on the drill press. The stops increment at 25mm, with different spacers for different offsets. A couple of my friends want this light bar so having the jig it will be much easier next time.


I used a system of spacers for the various mounting holes (over 300 holes drilled, half tapped), so I could get sort of an assembly line going. Measuring one at a time would have been miserable and error-prone.*






The channel and sink extrusions were slightly curved so I hand filed them flat for better heat transfer. That was before I discovered fly cutting, which is why there are still saw marks on the fins.


These M3 screws will also hold the star boards.


The acrylic faceplate (.220” thick) was drilled, tapped every other LED and fastened with 3mm machine screws and sealed with flowable silicone. The normal material used for this is polycarbonate, but polycarbonate yellows in the sun, acrylic does not. I’ve noticed lots of light bars turning yellow. Yes polycarbonate is stronger but 16x stronger than glass is good enough for me. Especially when glass itself is good enough for the windshield.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #2 · (Edited)
180 holes drilled for LED and heat sink mounting, 75 for current drivers, 24 for end plates, 3 for the power cable, 88 for the faceplate, 4 for the mounts, 1 for a Gore vent.
375 holes drilled, 228 hand-tapped.


Ready for first coat of paint


Cree XP-G3 70 CRI minimum. 4000k for a neutral white. SinkPad MCPCBs. Reflow soldered on the electric stove.


45 LEDs in gangs of 3. Soldering the wires with an iron was challenging. The copper boards are amazing at pulling away heat.


Russian LED current drivers from eBay. Configured for 2A. There are lots and lots of current drivers on eBay but I liked these for compactness and no frills - no silly strobe modes etc.




14 ga power cord. Space is so tight I used the chassis for ground to eliminate one wire. Even so, that 14 ga white wire barely fit. Lens mounts epoxied in place.


15 current drivers, blue tape to hold them in place while soldering.


I could have made the frame taller so the current drivers wouldn’t obstruct any light, but my first priority was minimum height.


Utterly minimalist design. I had a crap $129 light bar which looked cool but didn’t light up anything but the dashboard. I’m over looks now and just want the visibility. People keep asking me why I took the bar off my car, because it blends into the roof rack and they don't see it. Deutsch connector mates to a Rigid wiring harness. Miraculously the living room carpet survived the project.


Temporary mounts cut from discarded HP server mounting rails and gas-welded to cheap roof rack. Building a custom roof rack and getting better at welding is the next project.


Not bright at all off-axis and it makes no wind noise


It hurts to look at, even at noon.


What looks like a light saber on the ground must be a camera artifact. no light actually falls there.
 

·
Registered
Joined
·
227 Posts
Nice work!
 

·
Premium Member
Joined
·
5,729 Posts
Lot of effort went into this. Nice work!
Wondering if you are using a combination mill/ lathe machine. Kind of looks like it in the photo.
 

·
Registered
Joined
·
235 Posts
Jesus that's cool. I've seen guys DIY LED flashlights before, but this takes it to a whole 'nother level. I admire your dedication. I would have given up once I figured out how many holes I had to drill.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #6 ·
Lot of effort went into this. Nice work!
Wondering if you are using a combination mill/ lathe machine. Kind of looks like it in the photo.
Thanks! The machine is my buddy's old Smithy 3 in 1 mill lathe drill. It's like a boat- it's better to have a friend with one than own one myself.
 

·
Premium Member
Joined
·
5,729 Posts
Did you do this to see if you could build a better light bar, the challenge of it? It could not have been to save a few bucks.
I know you enjoyed building it.
Yes, if you occasionally need to machine, a friend with a machine is great. Better yet, have them do the machining for you.
Well, I guess I am the guy that does the machining for my group.
Been awhile since I am recovering from an illness.
Also getting old. My vision sucks due to two detached retinas.Hard time reading the dials.
Just bought a DRO for that reason.
Sorry for the rant, just happy to see people who enjoy challenges like your project.
By the way, I have no clue about electronics.
Reason I spent over a grand on my light bar.
 

·
Premium Member
Joined
·
5,729 Posts
Thats... pretty impressive to say the least. Not sure I would have had the patience to do all that. Then again, I don't have access to all those nice tools...
I have the patience. I have the tools. I just don't have the skills( as far as electronics although I did have NASA soldering certifications).
There are those who can and there is those who can't!
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #12 · (Edited)
Did you do this to see if you could build a better light bar, the challenge of it? It could not have been to save a few bucks.
I know you enjoyed building it.
You know me better than I know myself. I started out with the idea of spending $300 to make a "$900" light bar, but then I got carried away and spent $600 and about 200 man-hours to make a...well, I don't know what to compare it to.
 

·
Premium Member
Joined
·
5,729 Posts
You know me better than I know myself. I started out with the idea of spending $300 to make a "$900" light bar, but then I got carried away and spent $600 and about 200 man-hours to make a...well, I don't know what to compare it to.
" Birds of a feather". I think people who are good at what they do are a bit OCD with a touch of ADD. I know I am.
Spent a few hours tramming my mill today.It was within a couple of thousandths but wanted it better(OCD)
A little tip when Fly cutting. Put a chamfer on the end of the tool bit.
Leaves a better finish and allows for a deeper cut when roughing.
 

Attachments

·
Registered
Joined
·
235 Posts
You know me better than I know myself. I started out with the idea of spending $300 to make a "$900" light bar, but then I got carried away and spent $600 and about 200 man-hours to make a...well, I don't know what to compare it to.
A small star. You spent $600 on an earthbound star.
 
1 - 14 of 14 Posts
Top