What’s the tradeoff going to a bigger optic?
More difficult design challenges if I stick with the Conrad heatsink base, but if I get a completely custom enclosure made… then there is no trade off, they are better optics, more intense beam, taller dimensions means less deck height to get them flush with the spots, and also a less intense source output size (45mm vs. 30mm) over twice as large will maybe be better for the lens (polycarbonate or acrylic) if there is dirt on it, as the Carclo has some SERIOUS heating capability. You can burn your finger within 5 seconds, not so with the Gaggione.
Cool, thanks for spelling it out. Still can’t wait for the finished product! 
Oooh boy, me too.
I have found a new driver that I am possibly going to use in the light bar. Made by Sure Electronics. Looks like a better candidate than the Russian drivers, which me and Bruno have found out there is a reliability issue with them.
This is a BOOST driver, capable of 50watts of LED.
” This product is a high efficiency, constant current andBOOSTDC/DC converter. It is featuring over temperature protection, LED open-circuited protection and LED short-circuited protection. Besides, this driver features small size, high efficiency, stability, long service time and easy installation.”
This allows 100% power output no matter what state of charge the car battery or whether the engine is running or not. I am going to find out if the modes are directly switched.
Going to order some Gaggione 45mm elliptical lenses and 4 of these drivers soon.
I like the idea of going with a high quality driver. It seemed to me like it was always the weakest link, previously.
Isn’t there any other good alternative?
I have a sure electronic boost driver but they are way too big for only 1.5amps. Its about 2 time more surface area than the round ones we are using from russia and a lot taller too.
Alternative? I am looking, and looking, and looking. Not an easy thing to find. :weary:
You are saying you have a 1.5 amp unit Bruno? The buck or boost version?
It looks like i might have to make a completely custom housing without the Conrad heatsink if I were to use this driver. OR, I make an external driver housing that is under the hood of the vehicle?
This one is not cheap, but did you see the high output Buck driver from MtnE?
Yeah, expensive. It would cost $160 in drivers for the light bar. :confounded:
If you don’t like the answer, maybe it’s time to ask a different question.
Just a quick recap, can you specify the voltage of each LED (any in series, like a XHP50/-70?)? Current to each LED? Modes, like high/low?
If you get hung up on the word “driver”, you might be limiting your choices. Something like a discrete solution, eg, a small controller and big-enough pass element like a FET, can work. Or big honkin’ resistors can work off some power instead of an active element. You might not even want to assume the lights will work from anything less than 13V (ie, battery actively charging).
Anyway, maybe I can kick around some (cheaper) ideas.
I would like to hear your ideas. I’m making a similar light bar that uses six xhp70. And need reliable devices to run the led just like the OP
Well for me, i want to keep it simple as possible, and to me that means using a ready made electronic driver with modes at least and on this unit that i just found it has the bonus of having over temperature, short circuit, etc. If it can handle a torture test that i throw at it, then it is a winner.
But if i dont think it is any good then i will have to get creative, or get a custom mcpcb made by Leo.
Depends on how much “headroom” (difference between Vf and Vbatt) you have. Too small, and you need an efficient low-dropout regulator. Too big, and you need efficiency like a buck regulator. Control circuits can be quite small and use little power, while pass elements need to shed heat and need to be mounted on something like a metal chassis. TO220 cases need to be inside, as the pins are exposed. TO3 and TO66 cases can be mounted on the exterior, as long as it’s properly insulated/weatherproofed (think of a guitar amp).
The LM340 can be used as a current regulator, not just a voltage regulator. Beefy resistors can burn off some excess power.
If it’s switching regs you need, places like Maxim probably even have “evaluation kits” that include the IC and other necessary goodies on a small PC board.
The more details the better…
And don’t overlook “outside the box” solutions like gutting car-usb chargers. Meant to plug into a lighter socket (12V in), and spit out regulated 5V (easily dropped to 3.xV for an LED), probably as cheap as dirt when mass-produced in the brazillions of pieces.
Sounds like a good candidate for my “outside the box” suggestion above.
Well it appears that you know your stuff, however, I really don’t want to mess with a bunch of homemade custom power supply circuits as these are going into light bars that people are going to purchase. Those car USB power supplies are unreliable too, IMO. I consider myself a naturally “outside the box” thinker and I have considered many different options, but the main point is to keep things simple and reliable. Keep the ideas coming, it is going to help me.
Does Leo’s company make integrated regulator circuits on their boards?
I agree with Lightbringer, look into non-driver solutions. I have been reading the thread but I don’t remember all the details. Are all the LED’s in a bar driven at the same time? Whats your max current expectation? Could you use one of the DPS5015 Power Supplies or one of its siblings that Texas_Ace found on AliExpress to drive the bar? I realize that the UI has a lot of stuff that you don’t need in it, but perhaps you and RD Tech could work out a custom solution based on the same technology. It would be very cool to be able to simply turn a knob to adjust the current limit on the supply which would ramp the LED output.
Eg, for 3A max, you could use something like this, directly:
which’d take 12V with up to 35V spikes (load dump), and you’d adjust the voltage to feed an LED and ballast resistor.
A 6V LED (XHP-70/-90) could then get up to 18W. Stick a 1Ω 10W resistor in series with it which you could predict would drop 3V at that 1A current. So you’d set the voltage to 9V.
The ballast resistor removes some of the sensitivity to voltage that the LED has, making adjustment less critical.
Ideally, you want a current regulator vs a voltage regulator, but they might be harder to find and not as cheap.
You’ve sure come a long way in researching your parts list. Please dont give up!
If you’re still looking for a custom high powered automotive LED driver, designed to handle the high voltage spikes from an alternator, check out my light bar thread. These do 13.5A @ 14.9V and are provisioned for variable dimming via a potentiometer, thermal protection for the driver as well as remote thermal sensor for the heat sink (current is reduced if the sink or driver becomes overheated).