A Tale of Two Cities - I mean C8s

I received several flashlights the other day from a very kind member, (but that's another story). A couple of them were UltraFire C8s. They have XR-E leds that must be in the 7000k range. They are so blue... I happen to have a couple XP-E2 leds lying around, (about 4000-4500k I believe), so I got this idea to swap out the led and keep the rest the same.


Stock XR-E on the left and modified XP-E2 on the right.

This is a very short story and there's not much to it, or much of a point, but it's a round about way to show the results.Wink


I took the hollow pill and slid in a short piece of copper pipe and topped if off with a copper disc. Just enough material to hep get the heat to the outside of the pill.


I kept the stock driver. The whole idea was to see what the XP-E2 would do, with the same driver, but I had to change the wires and use some 22ga teflon coated, silver plated stuff. I couldn't stand that stock 30ga wire.


So it's done. I just used a tiny bit of Fujik under the star. I ended up taking a locating ring from an XB-D and opened it up to fit around the XP-E2, to center the reflector.

Ok, so what's the derned point?

Stock C8:

1.5 amps on high with a fresh 18650

24,000 lux at 1 meter.

Modded C8:

1.8 amps on high with the same 18650

34,200 Lux at 1 meter.

I was surprised to see the higher amperage, but I am thinking possibly this driver is DD on high. I didn't bother to check Medium or Low, but I will have to check now. That might, or might not, tell anything at all. If High is DD, then Medium and Low should be the same on both lights, since they would have to be regulated.

When it gets dark, I will take some comparison beam shots. There's a big difference in the beam pattern.


XR-E on the left and XP-E on the Right

Mouse Out is the XR-E and Mouse Over is the XP-E


Looking forward to the beamshots!

XP-E2 will see more than 3A in direct drive.

If the XP-Es are from IS they are around 6500K. Or did you get them from somewhere else?

If the emitter is seeing 1,8A, it would greatly benefint from copper MCPCB.

Beam Shots are up now.

On a chart it might, but it is not probable with the human eye, to tell the difference between 340 and 440 lumens. It only matters in one’s head, not in one’s vision.

The increase may not be that noticeable but in the end jump from 340 lumens to 440 is 30% more lumens, the same should apply to lux value bumping it up to about 44,300 and that is almost TWICE the stock XRE. That sounds like a lot of improvement, isn’t it?

+1 to what others said above me..

So why not put in a 1amp driver and call it a day? You wont see a difference between that and 1,8A on aluminium.. But the heat and battery time will be a huge difference.

The point is, if you are going to upgrade something, you might as well get the full benefit out of it. An XP-E2 should ideally not see more than 1A on aluminium mcpcb.

Why did you make that copper piece under the mcpcb, you will not see the lumen increase and no one will notice any increase in LED life.. It only matters in your head..

You got two similar lights right? You got a lux meter. You got an IR gun to measure heat on the body? why not compare these mods.. That would be an interesting tale of two/four cities.. :)

1,8A driver + XP-E2 on aluminium + stock pill

1,8A driver + XP-E2 on aluminium + copper insert in pill - done

1,8A driver + XP-E2 on copper + stock pill

1,8A driver + XP-E2 on copper + copper insert in pill

(Ideally, a 5x7135 driver should be used, just to easier get the same consistent emitter current..)

I don’t care about planes. I don’t fly. I think of them as ones that have working engines and ones that are falling out of the sky. Doesn’t matter which engine it is.

I just kept the same driver, to see what it would do. Why copper? because I didn’t have any aluminum in the right size and I do’t think completely hollow pills are good for anything.

I know you guys are all gung ho on copper stars, good for you. Do everything with a copper star, it's all good. Doesn't mean I need to, but I imagine I will have to start now, because everyone will want everything on a copper star, just because it's the "ultimate" thing this year. Two years ago, no one would have thought it possible. I never did copper because it was so much better than aluminum. I did it because it was easy to use copper plumbing fittings and copper discs. Copper was also easy to work with and there weren't any aluminum plumbing fittings or discs available.

I didn’t mean to sound offensive in any way to your choise of components. My point was to put numbers to show someone that may read the tread later and dropping the idea of copper star beacouse ‘there is no noticeable difference’ statement witch is not enitirly true. This little light with the emiter choise of yours is targeted to be small thrower and an additional 30% increase is a substantial one.

I am new to the forums and the last thing I want is to upset someone that has given so much to the community and showed us over and over again that you don’t have to spend tens of dollars to improve a light.

You are not upsetting me at all. You will find some of us tend to get excited in discussions, but it’s all good… as long as you don’t call me late for supper!

XR-E on the left and XP-E on the Right

Mouse Out is the XR-E and Mouse Over is the XP-G

Thanks for the pictures.
Do you have a long shot of the XP-E?


Even you can figure that out, cantcha?

Sorry. I’m getting oldeeeeeeeeeeerrrrrr. I thought you went sick testing lots of led’s.

They did show very brightly!

Hey Old-Lumens, I was browsing soldering irons which eventually led to looking up soldering videos and I came across your Youtube Channel! (I’m assuming it’s yours, unless there are two Old-Lumens running around modding flashlights) I wanted to say thanks for posting those videos, a lot of helpful tips and detailed tutorials. The copper heat sink was AWESOME!

Thank you! :beer: