2.4A Driver for XP-E2

I am currently running a green XP-E2 off a Mtn Electronics 2A buck driver (chosen for 2-14v input range). Host is a UF-T20

I would like to run this LED at the “max” of 2.4A, is there any way to get this extra amperage from this driver? Or possibly a different driver with a similar input range?

If it has 7135’s you might be able to stack another. for another .375A

Correct me if I’m wrong, but I don’t think it does.

Don’t look like it does. Sorry.

Well, you could probably find the sense resistor on that driver and trade it out for another value that will give you the current you want. I’m sorry I can’t help you with actually how to do that. :person_facepalming:

Another option is to swap the driver out for a regular 7135-based driver, like the Qlite, which Richard also sells at Mountain Electronics.

Edit: the Qlite won’t have the voltage range that your current driver has. What cells are you using?

Seams like he wants to run 2 cells.

The hope would be to run it off 12v power from an ATV or similar. For now I can run off a single 18650, just trying to lean towards my end goal which is vehicle power.

Well, like I said, somewhere on that driver board is the sense resistor. It has some value to correspond with the current rating of the driver. Changing the resistor value will cause the driver to target a different current output. Since Richard sells the driver on his site with a choice of which output (1A or 2A), he obviously knows which resistor to change, and could also tell you if it would be a very bad idea to do so. :wink:

The 1206 resistor marked R180 is the sense resistor. Adding another resistor on top (lowering total resistance) will raise the drive current however that inductor looks tiny, it’s probably already at or even above saturation current. I wouldn’t expect to see any gains and likely you may see performance decreases or even kill the driver.

FYI, 2.4A won’t give you much more brightness compared to 2A.

I was just gonna mention that. Also, that’s cooking an E2 chip pretty hard already, so it’s probably already peaked at output or may even be on the decreasing side of the parabola, no?

Like, you won’t be gaining 20% more lumens (6 vs 5), as its output may be quite flattened already if not decreasing with more current. But moreso, the visual difference will be negligible. Switching between 2.0A and 2.4A and back’n’forth, you’d be hard-pressed to tell any visual difference at all.

Yah, here ya go…

On an Al star, it’s already peaked at about 1.8A and light output will decrease with more current.

On a Cu star, the difference on the graph is 460lm at 2.0A, and 480lm at 2.4A. 400mA more current (20), only 20lm more light (4).

GUARANTEED you wouldn’t be able to tell the difference visually, even side-by-side.

Similar (worse, actually) for green XP-E2s.

I have made four XP-E2 lights, two of them are in identical convoy C8’s, one is running 1.9A one is 2.28A, i don’t think i can tell the difference between them (they are both red)
later when i made my green XP-E2 i just made it 1.9A again, i personally prefer the better battery life and less risk of burning out the diode compared to and extra 20 something lumen

12v input, you could get a buck driver and run just about anything you want.

It doesn’t sound like there is much point in pushing the LED harder. Hopefully a wavien helps me get the extra output I’m looking for.

Well, whut’s it in?

If a C8 host, you can try a C8F and have triple emitters. Even keeping the same current, by cutting the current each LED sees down to a third, they’d be way way more efficient.

An HS-802 host has a much deeper reflector, and would convert a marginal amount of what would be spill (ie, wasted light), into hotspot (ie, usable light).

And a wavien coller wouldn’t help, at least I wouldn’t think so.

For white LEDs, it helps “recycle” wasted photons by bouncing ’em back to the phosphor layer to be reemitted. For monochrome LEDs? They’d just hit the silicon and try turning the chip into a photodiode.

Currently it’s in a Uf-t20 Aspheric. A small light with a very tight beam is the desired end state. Specifically I want to see the beam itself as much as possible, hence the green (blue would also work). It is this reason I am looking for single emitter as well.

I am intrigued to try the wavien collar on a solid color led. One of their claims was increased output on solid color emitters.

For anyone interested djozz has tested the colored XPE2 leds. This is the link.