Two of my Cree Q5 lights has gone dim.....

Two of my fav lights, Fenix T1 and Eastward YJ-XAQ5 that I got recently has both dimmed down by about 50% or more.

First it was the Eastward as the beam became really yellow tinted.
The brightness got severly impacted also and it is much much dimmer.
Same with the Fenix T1 which I only received on Wednesday... =(
It was great the first day, super bright but now after 3 days, it's DIM.

In fact, Fenix T1 with no matter what battery I use is about 100 lumens now.
My KD Buckle Q5 AAA light rivals the T1 in High mode! Serious issues here. =P

Only thing I notice is that the yellow core is a bit darker in color than the other good Cree's.
Fenix T1 is not that noticeable yet. But still can see the difference against a good Cree Q5 I have.
Eastward light's Q5 has really gone dark yellow inside the emitter. Tint of beam is like a xenon. =P

I've owned and used MANY lights (as many here would already know) but these two are the first ones ever to do this.
Also, I've definitely not done anything "stupid" or do something which should not have been done that's for sure.

Does the new silver cree's have a higher failure rate?
Has anyone else had such issues with their Cree emitters?

The T1 should be under warranty rite?

Send it back and get a new one??

Not good news. My only Fenix silver cree Q5 is fine so far.
Thanks for letting us know BB.

I had this happen with an SSC P4 emitter that I tried overdriving with a 14500 cell when the light was rated for use with an alkaline 1.5V AA. It was really bright for a couple of minutes then went dim and couldn't be resuscitated. Maybe this is the price we pay for buying "overdriven" emitters. It seems that brighter is better, so many manufacturers are overdriving emitters. Even if the LED doesn't dim in the first few hours of use, it may have a drastically shortened lifetime from the usual 50,000 hours.

I would ask what cells and charger you're using for these lights. One light going bad could be a random failure but two... I think you're right to suspect something's wrong.

First check if its the tailcap or something in the switch. Use a small segment of wire and touch the battery "-" terminal to the flashlight body. If the problem consistently goes away with the switch wire-bypassed, then chances are its a switchcap problem.

If its possible to do so, you might want to try tightening the switch assembly a little so its tighter in the cap. I had to do this on my superfire.

Something is seriously wrong that two completely different lights from two completely different companies have the same exact failure.


I would suspect something to do with their current environment, cells, etc as being the culprit.

DX6090-silver backed P4 = no problems
DX11836-silver backed R2 = no problems
lowes task force-white backed, 3 wire Cree of some sort = no problems

knock on wood

The DX drop ins are all the same color phosphor surface. The Lowes emitter is more cream colored than yellow.

I wonder if internally they both use the same click switch?

I've tried the wire / multimeter switch bypass. The brightness does not change with the switch bypass.
Also, the switch has no resistence when on for both lights so I guess it's not the switch issue.
I can clearly see that the emitter is a lot darker than it should be. Especially the Eastward.

Also, Eastward uses 18650 and Fenix uses 2RCR batteries.
I've tried various brands of batteries but still same result. =(

No other lights have this issue. I haven't done anything different nor did the environment change in any way. Just bad luck I guess...

Interesting. LEDs are not necessarily bullet proof, so you could have gotten a bad LED or two. Or the circuitry maybe was faulty and over-drove the LEDs to failure?

I'll be keeping close eyes on my Q5s but they all seem very pristine and bright so far.

Nah, I've got the real answer. See, they were in the production process, when a big earthquake hit. So everything was shaking, and the exacting standards needed probably got thrown off!

Seriously though, I wonder if that's even possible? Could an entire day's worth of Crees be a bad crop? Anyone know?

I would call it Incidence,

last week my DSD-Charger died and yesterday my 17 month old Sony Notebook-charger died, would you call that purpose?

I don't give a sh** about the DSD, but Sony charges 120 Euro = > 180$
for a new one. So time for me to search Egay for an OEM...


I had one Cree fail the same on me...

Just bad luck


MfG Mr.Urahara

very unlike two different lights go wrong at the same time.

Is it possible that You inserted the Batts wrong way once?
Or possibly the batts are gone wrong - do they work good in another light?

bessiebenny said:

I've tried the wire / multimeter switch bypass. The brightness does not change with the switch bypass.
Also, the switch has no resistence when on for both lights so I guess it's not the switch issue.
I can clearly see that the emitter is a lot darker than it should be. Especially the Eastward.

Also, Eastward uses 18650 and Fenix uses 2RCR batteries.
I've tried various brands of batteries but still same result. =(

No other lights have this issue. I haven't done anything different nor did the environment change in any way. Just bad luck I guess...

Click to expand...

Its sounds like you started to burn out the die or the phosphor in front of it from power, but since I haven't seen them I will say up front this could be wrong.
The question I want to ask is were you doing some kind of run time testing on these at full power when this problem occurred with each?

I haven't even conducted any runtinme test with Fenix T1.
I only got it 3 days ago and have used it all up around 3 hours or so.
My batteries work fine on all other lights. (I have about 10 RCRs of various brands)
I've also tried using Panasonic / Trustfrie CR primaries. Still same.

In high mode, Fenix T1 is as bright as the 1W Cree lights such as the Ultrafire C3 AA.
There is nothing that I could have done to contribute to such occurance.

Eastward was tested with runtimes when I first received it. It went through fine as shown in my runtime graph.
Then I have used it without ANY issues for about 2 weeks after. But suddenly, it started getting dimmer. =(

Anyways. I guess I have to fork out the shipping cost to send it back to fenix-store.
That's about $15-20 and I was planning to spend that money one a different cheap flashlight.

I wanna cry..

Almost all of my LED lights are Cree Q5's. The only one that went dimmer is the P2D I accidently placed 8.2 volts on for a split second.:mecry:

However I did buy some Ultralast CR123 batteries once and could see a slight but noticible difference in output between them and some Streamlight CR123 batteries I had at the same time. Not to mention the Ultralasts only lasted 50% as long as the Streamlights.

Bill

Well, all I can say is that I'm very unlucky with the recent lights that I've been getting.

My recently-rebought Romisen RC-F4 is very dim with 2RCR.
It is about a third of brightness to when used with 1 x 17670.

Then it's my EastwardYJ. Then the Fenix T1. =(
All my previous 30 or so lights never had this issue.
So maybe the air around me has gone bad or something. =P

Just to givwe an idea of how dim.

My Eastward used to get 195 lux in my light box. Now it gets 80 lux.
My Fenix T1 used to get around 200 lux also in lightbox. Now it gets 60 lux!

That's both in High mode. Low mode is also much lower.
(which may be a good thing for those who wanted lower Low. =P)

I've got a few more lights to review so I'll see how they go.
- Aurora AK-P7
- Ultrafire Stainless Steel C3 Q5
- Romisen RC-F4 Q5 (thanks to lightbug!)

I was going to review my Fenix T1 but now I can't.... =(

Did you take voltage readings of all your batteries to see if any are acting funny after being fully charged?

First thanks for all the great reivews you've done!
Do the lights that are failing draw more or less amps than before?If it's the same then the driver must be OK and the Q5 is the weak link.Maybe just a bad run of Q5's.If it is a bad run then you can be sure someone else will post.
DON

BTW you are responsble for my growing romisen collection and ever shrinking bank statements