L2D turbo setting, bright then dims

[tozwp]

I've had my L2D for about a year now. I have one of the few that has the Rebel 100 LED as I received it just before they quit shipping these. I use it nightly on walks near a lake I live on. I usually walk the shoreline shining it into the water on turbo mode for several seconds at a time. Lately I've been noticing that the light seems dimmer than when I first received it. Tonight it wouldn't shine any brighter than low mode in any setting. I changed the batteries and now have all modes back but the turbo just doesn't seem as bright as it used to be. When first turned on, it is very bright for about a second and then dims (in turbo mode). Not sure if this is the way it is supposed to work but I don't remember it doing this in the past. I always use rechargeble NiMh batteries - usually 2650 Ultralasts but occasionally I'll use 2000 mAh Eneloops. I've never discharged the batteries to the point where the light doesn't work (other than tonight maybe?) and usually just throw them in the charger every week or so. The light gets used maybe at most an hour every week and even then, only a few minutes on turbo. Usually its just the low setting to alert cars when I'm walking. Does this sound like normal behavior or could it be that the Rebel LED is going bad? How could I check?

 

[Marduke]

see this?
http://www.candlepowerforums.com/vb/showthread.php?t=186488

 

[tozwp]

Yeah, I remember when that came out and it was a few months after I had received my L2D. I don't know if the LED in my light is bad or not. How do I tell? Were there 'good' LED from that batch that never experience a problem? I'm wondering if I should just send it back and have it checked out or get a replacement Cree. I was hoping someone here could give me a simple test to determine if its good or bad. Thanks

 

[diff_lock2]

Maybe the led is getting hot really fast. Excessive heat will cause a led to output less.

This could mean, that some how, the led has lost its thermal contact with the L2D's head, or the ambient temperatures are too high.

Maybe internal temperatures over time have changed the performance of some of the circuits components, such as caps.

 

[tozwp]

Doubt that its the ambient temp as it was only about 25 degrees F here last night. I did check all the contacts and they look clean. I checked the switch in the back - it is securely tightened.

 

[Jarl]

I had a rebel that went bad and it didn't exhibit the behaviour yours is; it dimmed down, stopped working, couple of days later, worked again albeit it very dimly, then a couple of days after that gave out it's magic smoke for me. The fact you still have all levels fine except turbo suggests that the LED is ok; try putting it on high mode for a few hours. It took about an hour for mine from becoming dimmer to giving out; if it's still working after a few hours, it's not the LED.

 

[jirik_cz]

Are you sure that you have fully charged batteries?

 

[Woods Walker]

I changed the batteries and now have all modes back but the turbo just doesn't seem as bright as it used to be. When first turned on, it is very bright for about a second and then dims (in turbo mode).

That sounds just like my L2D Q5 when the battery is lower. The Turbo is first to go out of regulation than the rest of the modes. I wonder if the NiMH batteries are shot and not getting a full charge.

 

[tozwp]

I'm suspecting it is the batteries now. I put in a set of Ultralast 2650's that had been charged a the prior week and they worked fine for several minutes. It then went dim and I lost turbo agan. I think these batteries must be rather lousy to lose charge that quickly. I'm going to run a newer set of charged Eneloops for a few days and see if I still have a problem.

Any suggestions for batteries? I like the self discharge and found a review of them on this site. I think next time I'm at Wallyworld I'll look for some of the Kodaks. Is there something better out there or is the low self discharge as good as it gets currently?

 

[etc]

Fenix L2D has some kind of buggy driver/engine electronics, I had two lites go bad on me in a similar fashion.

 

[Jarl]

Any suggestions for batteries? I like the self discharge and found a review of them on this site. I think next time I'm at Wallyworld I'll look for some of the Kodaks. Is there something better out there or is the low self discharge as good as it gets currently?

Spend the $$$, get some eneloops, and never look back

edit: woo, 1234 posts