Finally - first LED killed

OK, in fact dying, but not exactly usable. Also - it's second one, but dead BLF Delight is nothing to whine about (2xAA was too much for it).

Recently after comparing my first 18650 light (504B with 5-mode R2 dropin from DX) to the newest one ("MRV") I was surprised with the lack of output of the former, but only until I looked at the LED which is now half black.

Seems that I now have some options:

- throw it away and use the opportunity to finally buy the bin M MC-E in a WF-501 for $20, swapping the dropin into the 504,

- try to buy an emitter and repair the R2 dropin,

- do both to have a great flooder AND something to put into the WF-501 :)

But the biggest issue is - I don't want to cook the more expensive MC-E, as I guess the heat issues will be even more of a problem than with R2 (?).

And yes, there was a thick layer of tin foil over the dropin.

Are P60 lights really not meant to be used for more than seconds on high?

I've run most of my P60 to cell cutoff on high. Stuff happens unfortunately. My reviews will alway say when things died. All the extra cooling they get on the lightbox is a fan pointed in their general direction. If they cook on that test, they probably weren't up to general use either. And I've not sent much back to DX. Mainly because of the damage I've done getting things apart to perform a post-mortem.

I killed a BLF DeLight with a 14500. To my surprise it lasted more than 10 seconds.

It is likely that if the dropin killed the emitter it did Bad Stuff to the driver too - I suspect it is giving a lot more than 1A now.

Me, I'd get the MC-E dropin and put it in a nicer body - the 504 suits fine for that.

My first LED kill was an SSC P4 that I fed about 9V to. It didn't like it. In fact, it never got as far as being put in a light because I killed it "testing" it. Do not use a 6 cell Sub-C battery pack known to hold its voltage at 90A to test LEDs!

3 of those cells might have been OK - 6 of them turned out not to be OK.

It was extremely bright.

Just not for more than half a second.

There are a few things that could cook the LED like that. Of course the first is that it was just being overdriven. That can kill a LED pretty fast. The other is heat. The most important part of getting rid of the heat is that the LED is properly attached to the brass pill with thermal adhesive. I have heard about LED's from DX being loose which means there is no thermal path to speak of and they simply can't get rid of heat (well, except the reflector will probably push the LED down pretty good when the light is all put together). So second most important is for the brass pill to dump its heat into the body of the light. So any of those, and probably a few more, could be the culprit. It seems to me that an R2 should be okay to run as long as you want without worrying about overheating. If you have a good thermal path, I think an R5 can be run for a while too. I'd be hesitant to run an MC-E or P7 for more than a few minutes in a P60 host based on how hot my much larger and heavier 2x18650 WF-1200L gets with a P7.

You could get an R5 LED, but you should probably get a driver as well. I think the stock drivers tend to be direct drive except for lower modes and strobe. Direct drive can kill an LED. The drivers with 7135 regulators are at least keeping the current to something reasonable.


I love the way you cut to the heart of an issue so fast. Wish I could put as much information in such a short space.

Keep up the good work!

@Don - thanks, nice stories, cheered me up :)

@brted - thanks - I was pretty confident the thermics are OK and the LED is not being fried, as the body went very hot, very fast. Guess I was wrong.

As for the R5 - if I go the "flooder" route, I'll probably go all the way and buy an MC-E - then R5 as an another, weaker flooder would be obsolete (I guess).

I think I'll look for other options :)

EDIT: Damn. Now also my most expensive flashlight is dead. Skyline I's led just lost it's 'dome'. I've had enough today

These days the R5 can do what the MC-E does and better. Unless an MC-E is driven to its full potential, the R5 is likely to do better. Most Chinese lights don't. There are a few that do.

But Ted got a disappointing output from his M bin MC-E dropin, I got a very good output from mine. Most of the other MCE/P7 dropins don't do as well as my R5's and all but one of my R5's came from DX.

I need to add an LED type column to the table.

I am a defender of the R5 also.

They can defend themselves in a reasonable range of meters in trhow (with the appropriate SMO reflector) as in my Fenix TK12 and MRV @ XPG and do the same in flood with a very low consumption as compared with other like MCE and P7, with OP reflector.

This low consumption has no impact on large amounts of heat to dissipate and allows some very good runtimes.(best than XRE´s)

IMHO they are the kings now and if you want pure thowers, the SST-50 are the best option now (I hope they fall in price soon).

Now that I've gotten better leads, I am measuring more current going to the MC-E. There is a lot of light, it is just spread out more. Based on your lightbox readings, I still don't think mine is as bright as yours though.

The R5 is a nice LED. It usually doesn't have quite the hotspot intensity of the XR-E R2, but it still has a nice amount of throw without too much spill. It is a much nicer and more usable beam than the MC-E which I've noticed has blinding spill that bounces off the ground and trees in the foreground, preventing me from seeing what is in the distance. The R5 doesn't eat up as much power either, so you will get longer runtimes than with a P7 or MC-E.

I've heard it claimed before that they're direct drive but I think it's wrong. For starters quite a few are rated to 8.4V or higher (the DX standalone dropins are 18V IIRC). It's clearly not direct drive at 8.4V, must be a buck driver. And I have seen some tests at higher voltages. I think the confusion partially arises because a few of them seem to have high current draw. Why I'm not sure. Perhaps the the wrong current sense resistor or some other screw up in assembly. Also the R5 dropins seem to have sometimes had a spotty quality history at least as of 2 months or so ago with some of them dying quite fast. I think some people are blaming this on them being overdriven because of being DD but I suspect the more likely factor is poor assembly, i.e. the LED isn't properly attached as someone mentioned. The fact that a number of them only die (but die suddenly) after only a few days also points in this direct. Of course perhaps the biggest factor is to be frank a lot of people on DX don't know what they're talking about.

One reason you may want to change or at least modify the driver is to increase current draw i.e. brightness. Many of them are still about 1A (my XPG R5 from LT seems to be, it's also fine at 8.4V but considering that it was sold with a 2x18650 body it most definitely should have).

Guys... according to Don's table, DX's MC-E is TWICE brighter than the brightest R5 he tested (R5-A3)...

If the only drawback is having less than half of runtime, I'm still sold for MC-E.

But if there's less chance R5 will burn due to dropin changing into a frying pan, I will reconsider.

I'm sure it's somewhere around here, but can you point me to a good R5 driver/emitter parts or a good (cheap) stock R5 dropin?

Preferably something brighter than Don's R5-A3...

As for the Skyline - I glued the dome back with some Super Glue (cyanoacrylate?) and except some minor non-transparencies inside it seems to be as good as new, at least when it comes to wall-hunting.

Hope the glue will stand the heat. Anyway - if it doesn't, I WILL rip it apart and put MRV parts inside ;)

Cyanoacrylate release vapors that the stain dome...also is flammable.

Im not sure but perhaps cristal epoxi may works better.

Most epoxies are not that keen on heat. But should last long enough, LEDs don't get that hot.

Most thermal adhesives like those used to attach leds to the heatsink are epoxy based I think. Don't know if the epoxy base is a special heat resistant one though. Obviously not suitable for re-attaching dome.

For the R5, I think the genuine Solarforce one use a AX2002 based driver so all you may need to do is change the sense resistor for improved current draw (make sure the other components are rated for your target current though) rather then the whole driver. The DX standalones may be as well I think since they're rated up to 18V.

I was only talking about the ones rated to 4.2V. If it can take 8.4V, then you are right, there is no way it can be direct drive. I only have one light that can take more than 4.2V. The way the current draw drops with the amperage on the 4.2V lights make me think there is very little other than direct drive going on. On a couple of them the current draw goes up as the voltage goes down, making me think there is truly some kind of buck circuit involved. Then the ones with the linear regulators stay nice and flat until they fall out of regulation.

Yeah for those 4.2V ones I don't know. I think the cheaper KD standalone dropins are 8.4V too but the ones that come with the cheap bodies are usually 4.2V. Depending on your requirements, getting one which is rated above 4.2V may be a good way to be fairly sure you get a driver. If you only intend to ever use 4.2V, then you may prefer a linear regulation rather then buck so perhaps get whatever and replace the driver (well if you get a 4.2V one, take it apart and find it does have AMC7135, you may only need to add another chip if there's space).

One difficulty with the current draw thing is it also of course depends on the Vf of the led which will vary. For example, the AX2002 drivers only have a 0.25V voltage drop but it seems to need a greater overhead then that to stay in proper regulation for whatever reason (some say up to 0.7V!).

I haven't taken mine apart but since it looks the same as the Skyray dropin, it probably has some weird driver (I found someone who took apart a Skyray on some Polish? site) that I can't find anything about (although it's definitely buck).