$2 Skywolfeye/Yunmai 1xAAA light

[Lynn LeFey]

I have been a fan of the little 'fauxton' light since finding them. They are incredibly handy things to have, and cheap enough to give away to folks who just need a little keychain light. The only downside is that they are completely disposable tech. When the batteries are done, it's cheaper to pitch it than to replace the batteries. I figured there ought to be a better solution for low cost.

To say that I'm 'not a fan' of the 9-LED 3xAAA cheap flashlights that can be found everywhere (the kind Harbor Freight gives away with the purchase of anything) is an understatement. Every single one of them  I've gotten, and that's something like 6 now, are rattly pieces of garbage that intermittently work. AND require 3 cells. AND weigh about 3.5oz with alkaline cells.

There have been a couple cheap options I've found. One was the CREE 'Ultrafire' light on Amazon, a single AA light. Pretty good, but the cost is creeping up on them. They WERE like  $3, and are now $8. I found another $4 light at my local 'Rural King' store, a 2xAAA for $4.

Then, while digging around on 'Aliexpress', I came across a light just labeled 'Yunmai'. It's a single mode single-cell AAA, with a pocket clip and tailcap button for about $2. On ebay, they are sold under the name 'Skywolfeye' or sometimes just 'Skywolf'.

If i had to guess, I'd say they put out about 50-60 lumens. So, they're a very bright little light. I'm still testing them, so more thoughts to come, but one of the best cheap flashlights I've found so far.

Here's someone else's review of it on youtube.

[Lynn LeFey]

Well... smurf.

I started doing a runtime test on this thing. I got three of them and was going to run one and test its output versus a control.

And it died after about 40 minutes. I don't mean 'ran out of battery'. I mean 'completely ceased to function'. Something in the emitter. The tail click rear button still works when put on another light.

I tried it again with another light and ran the battery down until the light was putting out under 5 lumens or so (54 minutes) with no problem, but a 1 in 3 failure rate isn't all that encouraging.

[El Corkscrew]

Yeah, not very encouraging... Thanks for the info! 

[Blackbeard]

did you try cleaning the threads and relubeing(also clean body tube rim, the bare metal that sits on tail cap), clean contact points with rubbing alcohol, tighten tailcap retaining ring? these are most common fail issues

[Lynn LeFey]

Thanks for the advice, but none of those things helped. Appreciated, though.

[Blackbeard]

Thanks for the advice, but none of those things helped. Appreciated, though.

well your only out $2 

[Lynn LeFey]

Thanks for the advice, but none of those things helped. Appreciated, though.

well your only out $2 

Exactly. And the other two I got still work.

[m47mu74nt]

Well... smurf.

I started doing a runtime test on this thing. I got three of them and was going to run one and test its output versus a control.

And it died after about 40 minutes. I don't mean 'ran out of battery'. I mean 'completely ceased to function'. Something in the emitter. The tail click rear button still works when put on another light.

I tried it again with another light and ran the battery down until the light was putting out under 5 lumens or so (54 minutes) with no problem, but a 1 in 3 failure rate isn't all that encouraging.

I got a similar behavior in a -lot more expensive- nitecore, looked like a bad solder that may have cracked because of the heat diff between emitter and surrounding components (mechanic stress due to dilatation?)
Which cree emitter is it in your light ?

[Lynn LeFey]

Which cree emitter is it in your light ?

Does Cree XPE-Q5 sound like a real answer? It's what's written in the item description. I know nothing about Cree emitters.

[m47mu74nt]

Which cree emitter is it in your light ?

Does Cree XPE-Q5 sound like a real answer? It's what's written in the item description. I know nothing about Cree emitters.

My MT06 had a XQ-E emitter, that is extremely small (1.6*1.6mm), giving a higher throw than a bigger emitter in the same reflector, but dissipating high heat on a very small surface hence the solder issue.

if yours is a XP-E as advertised, then the emitter is 3.45*3.45mm which should be big enough to prevent most heat problems -if the underlying engineering is properly made-



btw, I am not sure we can trust any of the datasheets of these lights, I found the following on amazon :
3500lm ? WTF?
XM-L ? ( a 1000lm max emitter ... and not from a 1.5V AAA...)

[Don Pablo]

Trust the official Cree manufacturers datasheets. 

XP-E is a led model, as m47mu74nt said.

Q5 is the bin grade. Higher grades have higher max output, and Q5 is average, outputting between 107 and 114 lumens when given 350 mA. The highest grade, R4, gives between 130 and 139 lumens at the same current, and the lowest grade only 56-62 lumens at 350 mAh. 

http://www.cree.com/led-components/media/documents/XLampXPE.pdf
(Page 24 of the linked datasheet)

P.S, if someone is reading this in the far future and the link doesn't work, pm me.  )

[Lynn LeFey]

Great info, Pablo. Thanks! 

I know basically nothing about emitters. Something i'm finding amazing though is the extraordinarily rapid improvement in small flashlights.

Even these lights, which I guess are pretty crappy by many standards, are STILL amazingly bright.

[m47mu74nt]

Q5 is the bin grade. Higher grades have higher max output, and Q5 is average, outputting between 107 and 114 lumens when given 350 mA. The highest grade, R4, gives between 130 and 139 lumens at the same current, and the lowest grade only 56-62 lumens at 350 mAh. 

I didn't find any info of production yields though, but I imagine that they make way more lower grade bins (which are failed higher grades?) and that the emitter price is closely linked to it.

[Don Pablo]

Q5 is the bin grade. Higher grades have higher max output, and Q5 is average, outputting between 107 and 114 lumens when given 350 mA. The highest grade, R4, gives between 130 and 139 lumens at the same current, and the lowest grade only 56-62 lumens at 350 mAh. 

I didn't find any info of production yields though, but I imagine that they make way more lower grade bins (which are failed higher grades?) and that the emitter price is closely linked to it.

I wouldn't know the grade numbers breakdown.
The way I'm imagining it works, the LEDs come off a production line, and they test them at a standard power and sort into bins based on the brightness result. 
It seems to me that Q5 is a like a average bin with so many LEDs going into it that all the cheap under $10 lights can use them.
I wonder what happens to the lower grades? Destroyed?

Even these lights, which I guess are pretty crappy by many standards, are STILL amazingly bright.

Would you recommend these as freebe gifts over the fauxtons? 

[Lynn LeFey]

Would you recommend these as freebe gifts over the fauxtons? 

Absolutely. For one critical reason... these are not as much 'disposable tech'. If the battery dies, it can be easily and cheaply replaced, instead of scrapping the whole thing.

They're also pretty amazing lights for the cost. They will probably be everything most people ever need from a little keychain size light.