Light Bar Build 2.0

This will be a work in progress.

I am still working on my first light bar build and here I am starting a second one already :stuck_out_tongue: That thread is HERE The problem with that one is that it is based on bulb that is unavailable to anyone else at a price that would make a build like that practical. This build will address that issue (I hope) and maybe improve on it.
In THIS THREAD by ImA4Wheelr he said in comment #2

Boldness is mine. When I read that I thought, Wow, that is really good to know! Got me to thinking, maybe 1/2 PVC pipe can be force threaded into a 502b, and guess what - it can!

In my thread on the previous light build of mine, keltex78 complained

Again boldness is mine. When I read that and saw that “unhappy face” I thought, well shoot, if you have to pay $11.99 for each bulb, you could just as well by an XM-L 502b for that kind of money. Actually you can pay less. About 6 months ago, I bought a bunch them on Amazon for about $8 each including shipping. They are no-name clones, but work well.

So with all of those thoughts, I came up with this. First the parts.

What we have here is
4 - cheap XM-L 502b clones
2 - 1/2’ conduit boxes
1 length of 1/2 PVC pipe
2 - threaded 1/2’ PVC adapters

There are at least 3 styles of conduit body’s available.

Need some of these

The first step, drill a 7/8’ hole in the face plate of the box. I decided how far apart to mount the 2 heads based on aesthetics, nothing more.

The blue PVC chips you see in the background was from a test hole on a piece of scrap PVC. The larger circular cut in the piece of wood was from cutting holes on my previous build.
The next step depends on whatever clone of the 502b, or 501b you happen to use. they vary ever so slightly in size. Depending on the size of the thread hole on your flashlight, you will either need to use ordinary 1/2 PVC conduit pipe or a piece of 1/2” thread PVC water sprinkler pipe. It has slightly smaller O.D. It is on clearance, end of season.

Force screw the pipe into the head of the 502b. Make sure the spring is fully compressed and the pill is forced fully forward. If not, it will rattle and not make good thermal contact with the rest of the head

I had to sand flats on the “nut” for clearance inside the box

Once the module is constructed, there are all sorts of options, this build is scalable.

modules can be spaced at arbitrary distances.

or extended into 2 dimensions.

These things can be strung out like tinker toys!
What I have not worked out yet is how to drive these. Off the top of my head it would seem that each head could be converted to direct drive and then wire each head in series or parallel depending on what other separate driver is used. Or perhaps the original drivers could be left as is and drive them with a master driver? I have seen some discussion here about this sort of setup, but never tried to follow it.

After this, who knows, maybe another with C8 heads :bigsmile:
I know for a fact that over on the DST thread DenBarrttSAR is talking about building a “”“SuperLight” with DST heads

Great ideas here! I'm interested to see what you come up with for drivers. I'm really liking these LM2596 DC-DC modules Comfychair talked me into. Really easy to use.


Would 4-18 volt buck drivers work if supplied from a 12 volt battery?

This is the part I am stuck on, I have to study it out or let someone point me in the right direction. I will start by looking at the LM2596.

Very inspiring, i have a spare head from a keygos M10 complete with LED and replaceable driver, i shall look into this

Oh man, I love this! I remember you mentioning this idea some time back, but I couldn't really picture it back then. Very cool concept. So many possibilities. Thanks for sharing.

What emitters? How many amps? 300 +/- lumens like the other build?

Thanks for the encouragement guys, I will push forward.

In this case they are XM-L’s The lumen output will depend on what driver and how hard they are drivin. I have to remember that in an environment like mowing a lawn, I can not drive them as hard as I would think.

Why doesn’t someone do this using the heads from a TR3-T6 :stuck_out_tongue:

You could get a four pack of buck drivers, as already mentioned. A four pack of 925ma from FT for $6.60 Single mode driver, you are not going for high/low beams? That should be 300+ lumens for T4-T6 XML’s.

this looks really awesome!


Wow, I don’t see how these Chinese modules can be made for that, seemingly impossible pricing :open_mouth: . These aren’t constant current though right? Are they being used direct drive?

No, CV only. There are other FET-based versions that do CC/CV and a max of 10 amps, but they're more money and don't come in a 10-pack:

I even have one (the cheap LM2596 version) being used in a under-shelf keyboard light on my desk, with a 12VDC wall wart for power and a 10 watt (3x3) array, with the onboard dinky pot removed and replaced with a remote pot mounted on a little angle bracket.

By the way, those super cheap 10W LEDs seem perfectly happy with having 3 amps @ 12v shoved through them, and at that level make a XML look pretty wimpy in comparison.

These are the ones I bought. Come with heatsinks mounted on the LM2596. Also shipped immediately

(few hours after my order) and comes from NY - you'll probably see them in 3 days.


Drivers are something that I never concerned myself about, therefore I have some catching up to do. The link you pointed me to describes this module as CC/CV, but you say no? What current can this module supply? and Garry, how much will the “more expensive one” you point to do?
I’m guessing that the way to go is a driver for each LED, so they need to be cheap. Am I on the right track?

BTW, FT is warning that they will be on Holiday from 10/1 to 10/6

the ones linked from comfy are rated up to 10a. the cheap 10 pack ones are rated at 2a or up to 3a with additional heatsinking.

what you could do is get the cheap 10 pack, and dial the voltage in until each emitter is pulling about 2.8-3a and you would be looking at over 3000 lumens at the emitters with 4 heads

You could get by with just two Buck drivers. As long as the battery voltage is equal or above the Vf of the (2)LED’s plus aprrox. 1.5V for the driver overhead.

Edit: clarify as Buck drivers

Can't the existing flashlight drivers be used if connected in series? The drivers should easily be able to handle up to 5v each. 4 x 5v = 20v.

EDIT: I guess it would be hard to keep them all in the same mode unless one could be made to be the master.

That's why I linked the ones with heatsinks - they are ready for the 3A load.

I was also going to ask what you were going to do with the stock drivers. Turn them into contact boards? You could also use the LM2596 boards to supply the correct voltage into the stock (or replacement) drivers. But if you not interested in modes (which requires more work for a momentary switch) then I'd just got from the LM2596 module to the LED.

Those 501b's won't be that great for an XM-L @ 3A (lousy heatsinking). Might want to tame them down to 2A or so. Are the reflectors SMO or OP? You'd probably want OP (or spray an SMO w/clear coat) for this application.

Got my wiring hooked up on my mower mod. Ready to put the modules in place and connect the LEDs! Slow, but it's coming along.


By the way, how much more mowing season you have left up in CT? We're almost done with mowing here. I'll mow once, maybe twice more.

I may have 2 or 3 more times to go. Come this time of year I start slacking on it