My new Flashlight loses brightness. What's up?

I just bought a new Romisen RL-B7 flashlight on ebay from an outfit in HongKong. The unit uses two 3.0 volt or 3.6 volt CR123As or similar. When I got it, I popped in two brand new Everready E2 lithium battiers and I was pleased with the light output. The light had about 90% of the brightness of my SureFire e1b Backup on shorter throws and might have eeked out a lead over the surefire in longer throws.

The problem is that one day the light began under performing, it's light output is down to about 1/3 of what it used to be and I don't know why. The batteries are still testing good (I hardly used the flashlight). I even replaced them with a brand new identical set and I am still getting crappy performance . Does anyone have any ideas? The light uses a Luxeon LED.

I'm afraid there is nothing I can do to fix this and I've only used it for about 15 minutes, tops.

Any ideas would be appreciated.

-FoF

Luxeon I/III/V or Luxeon Rebel? In the latter case the emitter could be part of the defective batch of RB0100.

If that's not the case, then it's either the driver dying (if it has an inductor it might be broken) or the emitter. I'm not familiar with your particular flashlight, but there have been bad designs that would let their emitters overheat during normal operation.

I once had a SF U2 where the emitter was dying ... which git dimmer and dimmer with use. In this case, you could see it starting brighter and then quickly loosing oomph. Does you light do this or does it start weak right away?

Something is clearly burned out. See if you can return it, otherwise figure out what you can salvage. If it's the LED that's burned out you can always learn how to mod and replace it.

You might try cleaning all the battery contact points with contact cleaner (Deoxit or Progold are great), or if you don't have any try using a bit of 70% rubbing alcohol on a Q-tip, being careful not to let any drip into the head (so hold the head UP).

Also, make sure everything is tight. It probably is some other kind of problem, but these are always good things to check with any new light. Good luck!

What I have found to be the case in most of the cheaper lights is that the LED is not properly heatsinked. This is the result of minimal heatsinking in general, or there is not any thermal adhesive under the LED star. When an LED is overheated for extended periods, it loses performance quickly. It will not recover once the damage has been done. Seek a replacement light, or consider replacing the LED.

Thanks for the suggestions. I am going to seek a replacement - if the cleaning trick doesn't help. This flashlight did noticeably heat up when left on for more than 90 seconds. Much more than my SureFire does. I wouldn't mind the heat - but I think the heat didn't do my flashlight electronics any good.


P.S.
Hey FallingWater are you really as hot as your Avatar? I'll bet you look just like Norm from Cheers in real life!:nana:

-FoF

If the flashlight is heating up, that's a good sign - it means the LED is sinking its heat in the light's body instead of leaving the body cold and barbecuing itself.
After this, I'm putting my money on the driver.

Oh, and I'm a dude my avatar is Lisa Miskovsky, one of my favourite singers

Just got a RL-B7 , Ive got 2x3v CR123A , cheap *** batteries in it and there is no real heat coming from the LED , looks like there is lots of thermal compound under the star .

Got some 3.7v CRC123A's on order . Nothing to fault ATM .