Is my red led WF-501B burning out?

[wahoowad]

I have one of these Ultrafire WF-501B Philips Luxeon K2 Red LED flashlights for night activities. When new it worked great, but after about 10 to 15 hours of total use (maybe 2 to 3 hours per night) I noticed it didn’t seem as bright with fresh flashlight and had a bit of flickering going on. (previously I posted about flickering and the advice received to tighten connections resolved that flickering). This new intermittent flickering doesn’t seem to be going away.

So I bought another one and I can tell it is much brighter and doesn’t have any flickering. So I guess I am wondering if these cheap lights simply have a limited lifespan…or maybe just this one is crapping out?

[Steve_the_Chief]

Can you unscrew the reflector to see if there is thermal compound under the LED star?

Did you wrap the dropin in aluminum or copper foil to improve heat transfer?

[islisis]

the first review in that link might give you a hint. flickering could be due to the heat too. it’s too late to save the old one, but you can plan ahead for your new one

i had a crappy red drop from KD which acted the same… jumped from 400mA to ~1.2A tailcap amps after 5mins or so
it’s due to thermal runaway and probably a crappy driver, the bulb should last a long time if kept correctly driven

read up about p60 drop in heat management to learn a about it, foil wrapping can help

[wahoowad]

I’ve done nothing to the light other than snugging up the threaded areas that were loose.

They don’t get as hot as some of my other 18650 lights - moderately warm, yes, but not uncomfortable.

This is all I can see. The white paper ring seems to be glued down. I didn’t want to pull up on it to hard to see if it would come off. Posting a pic below although Photobucket screwing up for me today on some other sites…

[Steve_the_Chief]

I'd suggest to do the foil wrapping and then see how warm it gets then.

If the light itself doesn't get as warm as your other lights that doesn't necessarily have to be a good thing.

[wahoowad]

OK, I’ll try it. Is the adhesive backed heavy aluminum tape good? Or just some folds of regular old household foil?

[Steve_the_Chief]

The bare metal foil is better. Some folks also use stripes cut out of soda cans.

More information:

P60 XML - which one to buy?

What P60 XML offering is the recommended one? I want something with at least two modes that can drive the LED to a good use but without heating too much. I'll use it in an UltraFire WF-502B host. (will I need to use aluminum foil for better heat management?)

Aluminium foil wrapping

I see that many people use aluminium foil around the dropin to help heatsink. So i want to try to understand the best way to do it. - What kind of aluminium you use, professional or "cooking" aluminium? - You use also thermal compound? Any photo or suggestion to do a perfect job are welcome.

[Steve_the_Chief]

Oh and by the way, I understand that you don't want to ruin your new dropin - but you could take the paper spacer out of your already broken one to see if there is good thermal connection from the LED star to the pill.