Friday, 9 May 2014

3x CREE XML U2 LED 4000Lm Dive Light Tear Down for a new video Light

Bought off ebay a triple XML torch for £30. It came from a UK seller and so arrived in 2 days but suspect it could be sourced more cheaply from China..

I'm following this thread as a lot of the hard work has already been done...

Here goes then:

 #1 Remove the chrome Bezel, I used some long nose pliers.. it will move but its very very tight...

This leaves the glass lense jammed in with an o-ring across the top. I used my nails to pluck the o-ring out.

The lense fell out with a little vigorous banging of the light head onto the floor. The LED module can then be pushed from the inside of the lighthead and it just falls out.

There is another smaller o-ring inside the light head, the glass sits on this and hence there is an o-ring above and below. You can easily miss this lower o-ring. I've left it in-situe as I'm not sure I can get it back in again.

Here is a top view of the LED module, the spring is in the centre and the hall effect sensor sits in a small groove in the metal casing. Interestingly, there is only one sensor while the slider knob, is pushed forward to make the light intensity increases. My only thought is that the magnet(s) in the slider has some sort of coding/positioning inside to indicate position on the length of the slide? Its seem to increase the light output based on the strength of the magnetic field, as you slide the magnet along it gets closer to the hall effect switch. Feels like 10 increments to full power?

There is a small knurled ring to keep the Slider magnet in place, this can be unscrewed enough to let the magnet come out. Might be tricky putting in back in.
The Light steps through 7-8 power steps as you push the slider forward.

To Disassemble the LED module, push a screw driver in the small slot opposite the hall effect sensor.

The reflector piece for the LED module can be detached by unscrewing it from within the LED module.

Once you have disconnected the reflector module, the LEDs are visible. These seem to be stuck to a washer liberally coated in heatsink compound.

Other observations:

I measured 2.26A on full power at the tail.

Alignment of the magnet slider and the hall effect switch is done by the LED module only fitting in two ways and its always aligned correctly, there are two notches on the module to align it.

The Magnet slider switch can be removed by unscrewing the knurled ring, pushing it back over the o-ring a little and pulling the slider out.

This is the underside of the switch, its got a small rubber insert which gives it the resistance when you push it back and forth.  After  a while I found the switch to stick, put some silicon grease in the slot, this seems to sort it.

Run times:

Initial test show:-

On TrustFire 2500mAh batteries from Dealxtreme, the light lasted ~36 mins...

On Xtar 2600mAh batteries from Amazon, the light lasted ~52 mins.

The lights don't gradually go out, they go off immediately.
The Trustfire are not 2500mAh, suspect they are a lot lower...
Need to double check all these time.. with another run...
I use my test rig here :-

Note the torch and sensor barely fit in the bucket.

Dived this weekend and noticed that the slider switch is impossible to feel in a pair of 7mm mitts, you just can't feel the knob, just have to rotate the light making the motion and hoping it engages and turns off.

It also started to flicker like mad after ~35mins full on use, it was so distracting (like a strobe) I had to turn it off. This makes me think it dies in different ways depending on the battery type (trustfires in this case xtars) . I'll do some more tests.

With the reflector in, its quite a floody light but because of its overall power it does throw a lot more that my other Chinese torch.

Pool shots of this triple XML light ( on left ) and the single version ( on right) with reflectors still in...

Triple light...

Single XML, much tighter beam below...

Single XML again..

Triple XML, less defined spot but much brighter..

All shots on manual 1/80 sec , f2.8, 1000 ISO, Canon S95 with Inon UWL-H100, FOV: 100.8° underwater.

Took it diving last week to 29m ( 95ft) and it was fine, vis was around 1-2m and it was dark, I actually prefered this light to my other Chinese single XML light.. The wider beam was actually more useful at this close range, wasn't much point have a long throw narrow beam.. Only issue for me is you need true >2600mA batteries to get an hour out of it ( two dives in my experience). Cheap batteries and it won't last the day..

In use at low viz... 28m..


  1. Couple of things 4 months down the line and 30 dives later...

    Not flooded which is good and i'm happy with the light, its a nice bright torch, hang it off a D-ring and leave it there.. fairly robust...

    The little rubber block used to give the switch its resistance is quite sticky now... will try to clean to see if that makes a different..maybe salt on the surfaces...

    You can't leave it in the kit bag with the batteries in... it always dead when I return to it a week or two later...( unlike the other Chinese torch I have) take the batteries out... not a problem overnight but I always tend to recharge the batteries and put them in fresh on the day I'm going to use it.

    Battery life... just about two dives.. I guess around 45-50mins total on-time.. in cold <15 degree water... you need good batteries for this one! I think this is the only issue, but more light = more power!

    Otherwise happy..

  2. Still my goto torch but some further thoughts:

    1 flooded this week in a lake, fired it up before it was completly dry and its fried ;(

    I bought another one about a yr ago which is still going strong but it appears to be slightly different, its not as bright as the first and is on/off rather than a gradual min/max power. Also it was marked 3X XM-L2 T6 rather than XML U2. So, they are not all the same even they look the same..