Which LED gives the highest sustainable brightness?

Flashlight Modding and DIY Parts
1

Maybe a noob question but I’m really curious.

Most of modern flashlights control their temperature and regulate the power accordingly to not exceed the set border temperature. Smart.

So the simple deduction is the less heat gives the LED at certain brightness the higher lumen it can sustain. So the two indicators I’d focus on are: temperature gain vs power and lumen output vs power.

I want to build a flashlight for my night bicycle rides which can sustain the highest brightness. I don’t care of power consumption. Nor cri or tint. But it needs to be 5050 or less.

Which LED would suit it best?

2

XHP50.3 in the highest flux bin you can find (which will be cool white, low CRI), XHP50.3 HI if you want more throw, at the cost of ~10% output.

3

Thanks thefreeman. Are there any other points of view possible? Or other nearly as good as the one above?

All in all highest bins are usually hard to get. Which particular one would you recommend among those avaliable at Kaidomain and Aliexpress?

4

The brightness would be proportional to the current.

The current would depend upon your battery pack— what is the A-Hr capacity of your cells and the duty cycle or duration of operation?

The design of the light and the thermal path would determine the temperature limit. Better heatsink gives longer run time for the same current.

The lifetime of the emitter is also related to the current.

5

XHP70.2 and 70.3 have very good efficiency. Sustained lumens are also affected by factors including thermal path, flashlight thermal mass and heat shedding design, LED driver, temperature control firmware/sensor.

6

Kaidomain have a good selection of XHP50 and XHP70 LEDs. I’ve bought a couple of 5000k/5700k high CRI ones (XHP50.3HI and XHP70.3HI) off them recently. Just be aware the screw holes in their LED boards may not match up with whatever you’re planning on fitting them in. I discovered that last night with one of their hosts. Guess I’ll be relying on the reflector to hold the LED in place.

7

To sustain high output you need good heat dissipation. Led on good star fixed to good host with screws.

8

The 3V version of the XHP50.2 (or 50.3) may suit given CRI and tint don’t matter to you- particularly if you’re looking at using single 3.7V cell.