Problem with Cree XML-T6

I bought this flashlight before I realized it uses 18650 batteries which I don't keep. So I decided to plunge forward and buy two UltraFire batteries with a charger. I put them in the flashlight and it lit up for about two seconds and turned off. I removed the batteries and one was visibly scorched on top and there was a burning smell. So I'm unsure how to proceed. Can the flashlight be converted to use AA batteries? That would be my preference by far. The tail switch screws off as does the head. Here is an image of the flashlight.

Oy vey.

What batteries you bought? Does flashlight have an extender tube to make it longer?
As it is on picture 2 18650 will not fit. Did you buy smaller Li-Ion batteries? If yes and light is designed for one 18650 then you had to much voltage. It may be linear driver in which case it is most likely fried (if you applied 8.4V to driver that can accept 6V top - e.g., most AMC7135).

It cannot be converted to AA.

Light looks like SZOBM ZY-602 CREE XM-L T6
Now, I assume you somehow had two Li-Ions inside because you wrote "removed the batteries" and "one was visibly scorched".

On DX website it says input voltage 3.7-4.2V, digitally regulated 2.8A output

From that it means that it is using driver with 8 AMC7135 chips.
Most of AMC7135 is rated up to 6V and even if they would be rated higher amount of heat dissipated in them with 8.4V applied would be too big.
If battery terminal looks burned it also means that most likely light went into direct drive and extremely high current was pushed thru LED, i.e., LED may be dead too.

Dispose batteries you bought. You should not buy UltraFire batteries, especially if you uncomfortable with them and prefer AA.
Throw light away and buy something decent running on AA (IMO too much hassle reviving $19 light).

Looks like a very generic, cheap budget flashlight.

Seems surprising that you would be able to fit 2x18650 inside the battery tube if the light wasn't designed for it. There's no possible way you could "accidentally" stick 2x18650 into a light designed for one 18650. I assume the problem is either cheap batteries or a short in the light itself. The light can be repaired ... but doing so likely means replacing the batteries, driver and possibly emitter. It may be easier to just buy a new light.

Converting the light to run on AA isn't really a practical option because 18650 are significantly wider and longer. A hobbyist could mod the flightlight to run on 2xAA, but doing so would require a lot of work. You'd need a new driver (the circuit board at the front of the light that the battery sits against). The tube would probably have to be cut down and new threads cut, which would require a lathe. And even if you did do all that, the tube is so much wider than needed for AA, you'd have to add some kind of plastic tubing on the inside of the battery tube to keep the batteries in place. You could skip cutting down the tube by adding a dummy cell in the battery compartment, but that's just extra bulk to carry around.

The conversion could be done... but it wouldn't be easy, might require special equipment and would leave you with a 2xAA light that is much bulkier than it needs to be.

arek98 said:

Light looks like SZOBM ZY-602 CREE XM-L T6
Now, I assume you somehow had two Li-Ions inside because you wrote "removed the batteries" and "one was visibly scorched".

On DX website it says input voltage 3.7-4.2V, digitally regulated 2.8A output

From that it means that it is using driver with 8 AMC7135 chips.
Most of AMC7135 is rated up to 6V and even if they would be rated higher amount of heat dissipated in them with 8.4V applied would be too big.
If battery terminal looks burned it also means that most likely light went into direct drive and extremely high current was pushed thru LED, i.e., LED may be dead too.

Dispose batteries you bought. You should not buy UltraFire batteries, especially if you uncomfortable with them and prefer AA.
Throw light away and buy something decent running on AA (IMO too much hassle reviving $19 light).

Click to expand...

Agreed.

I'm scratching my head trying to figure out how he managed to fit 2x18650 inside a light that only fits 1x18650. Perhaps he stuck 2x16340 inside?

The tube is long enough to accept two batteries. The flashlight itself if quite stout. It would make a great club. From what everyone says it sounds like I should just let it go though. Too much hassle. Thanks for the advice.

Eh, I just checked with some friends who also jumped on the same "deal" and one of them also has a dead light. I think I bought a crap light.

Hmm, so it is different light than one in picture you posted?

If you decide to go with 18650 buy good ones. Panasonic are very good and they are available in many kinds and brands (with added protection circuit and wrapped). Some examples in random order: Orbtronic, RediLast, EagleTac, Callies Customs, Xtar, Intl-outdoor
See here: http://lygte-info.dk/review/batteries2012/Common18650IndividualTest UK.html

Keep away from xxxFire batteries! Currently highest capacity 18650 is Panasonic 3400mAh, anything claiming more is not true.

You may also want to buy ones with button top, some lights will not work with flat tops.

Also make sure you have a good charger! Xtar makes nice chargers. See some reviews here:
http://www.lygte-info.dk/info/indexBatteriesAndChargers UK.html
I'm not sure what is a newest model but I'm sure you can find this here on CPF

There is an adapter into which you can insert three AAA batteries. You the insert the adapter with the the batteries into the flashlight. You should have received this adapter with your flashlight.