Results: Testing XM-L, MC-E, SST-50, and XP-G emitters **Updated**

And what would be a similarily "bold" current for an XR-E?

oldbobk,
So are you saying the affect on runtime is negligible between running 1.4A vs. running 2.1A? That doesn't make any sense to me.

I also don't know if I'm up to the challenge of removing two of those chips! I'd probably look into the newer KD driver (and deal with a lousy low, or go 2 mode).

-Garry

The difference in run time with a 2400mah battery would be about 100 minutes for the 1.4 and 70 minutes for the 2.1 amp high, but I never use high when I am concerned about runtime.

Send me a PM when you are ready to remove the chips I can walk you through it or I can send you one premade if you want.

Thanks for the offer Erik! I am definitely keeping you in mind for a custom P60 drop-in or even just a custom programmed driver (think I'd like Medium a bit higher than the usual 30%, or even 4 brightness modes) for another mod.

100 minutes vs. 70 minutes sounds considerable (for my application), so therefore I don't see the gain of 50 lumens worth the 30 minute trade-off.

-Garry

Don't want to be a spoilsport but please remember that Match's curves are only valid for a heavily cooled emitter. The top points for the curves in real life lies at a much lower amperage because of the generated heat .

[EDIT]: Calculations using Cree's derating curves give me for a "normally" cooled flashligt a top on the curve at an LED output of:

370-400 lumen @ 1.8A for XP-G R5 and

730-780 lumen @ 3.5A for XM-L T6

but the top 30% of the current only add about 12-15% of light output.

OTL (out of the lens) output normally are about 80-85% of the LED output.

Yet another reason for me to stay back to 1.4A / 1.5A!

-Garry

Possibly the most informative post for us modders on this forum. I've actually photographed the charts to my phone for easy reference.

Thanks Match!

yeah XR-E q5 Wink one day when time permitts

Can't a few of us donate $1 or $2 to Match so that he can test a XR-E Q5 and R2? (I'd be willing )

I’m in if Match is willing to do it. I’d love to see what an XR-E can put out and what difference there is between an R2 and a Q5.

don't worry guys, it is in the works (well, at least the R2)

What about the newest Cree's, any plans, I realise they may not be power houses so maybe not much interested?

Yup. Thanks to dthrckt graciously sending me an xr-e r2, it will soon be tested along with a direct to copper mounted xm-l.

Gentlemen,

The initial star mounted test for the xr-e r2 is complete. The first post has been updated to include the graph. One of these days I'll go through and clean up that first post.

Thanks again to Dthrckt for sending me the emitter for testing....and yes, I'd like to someday get around to testing the new Cree flavors too... I don't need the money, but if y'all could somehow paypal me "15 minutes" that would really help :)

-NeedsavacationMatch

Thanks Match! So it's not worth going over 2.0A. Guess you didn't test it to the point of "pop, burn, fizz, fizz". How was the heat generated at 2A? Manageable for a decent heatsink setup?

-Garry

Thank you Match!

Overdriven XR-E lights seem to be quite popular right now.

Thank you (again ;-) ) Match. Those last results show why xre are still all the rage in flashlights. And a super duper reference as always.

Thanks guys, glad you can use the data.

In a typical star mounted application, regardless of whether or not the led star is mounted on 3lbs of copper or not, the answer to you question is no...not worth going over 2a. If it responds anything like the xm-l did, then the bottleneck is the star. As soon as I get some time, I'll remove the xr-e and directly mount it to copper and retest.

There was no reason to take the xr-e to failure, as the breakover point for output was 2.1a. More importantly, I want it alive for the afformentioned test. As for the heat, think of it in watts for easy comparison. 2a x @4v is about 8watts. Compare this to @ 9.5-10w for an average driven xm-l.

great work, Match! this has got to be THE most useful thread in the 'flashlight web'

As for the XB-D and XT-E, Cutter doesn't have any 4 xb-d PCBs. I suspect the one up versions of each will find some niche w/ beam profile or tint, and maybe eventually price, but I doubt we'll select them for throw or high output. Still, the data will be useful when you do get around to it.

I, for one, will be much more excited about the direct copper mount results :) Still, you shouldn't feel pressured, that would take the fun out of it, and if that happens, what's the point!

I hear that! I spend so much time fixing and maintaining my 'stuff' (particularly IC engines and whatever they're bolted to) that I don't feel like I own it - it owns me!

Thank you for all this information. This is my one of my favorite threads I have ever read and like the updates.

Thank you! :crown: H)