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Thanks to Aurabuy for sponsoring this review 
The KX-H02 is available for $18.52 shipped. Stock image:
It has more of a hot spot than the above image suggests. Closer to this:
I guess I'll start by quoting specs and commenting on them.
This is your standard clicky switch. It also protrudes from the back so you cannot stand the light on end.
INCORRECT. There is only high, low, and strobe. Although it is entirely possible they are "hidden" modes and I don't know how to activate them. I prefer this configuration anyways, myself. Measured 6000 lux on high, and 2200 lux on low at one meter.
INCORRECT. You can clearly see from the stock photos that the reflector is (what I believe is called) an "orange peel" type.
I'm not sure why so many people call this a lens. It has no refractive properties. It is simply a window - A flat, circular pane of glass.
Heh, no. It's bright, but not 150 meter bright. I realize this is rather subjective, but 50 might be more reasonable.
Eh... I don't think so. Not unless you're using a state-of-the-art >3600mAh brand name cell, anyway. It draws an amp when in regulation, so 2-3 hours is more typical. It draws 1/3 amp on low, so that should last a good 8 hours or more. Here is a graph of battery voltage versus battery current. And since it is a linear driver, the battery current is the same as the LED current.
Now, according to the cree datasheet, the LED should be dropping 3.7V at 1A. So how is a linear driver staying in regulation at 3.6V? I characterized the LED, and it is quite unique:
So what's going on here? I've never seen a white only drop 3.1V at full current. Is this a special bin they're pulling from? I checked another XRE I had lying around, and it dropped 3.7V as expected, so I'm pretty sure I'm not doing anything wrong. If anyone has any ideas, let me know. :can:
This one has O-rings in the right places. It would be fine with a splash, but I'm not sure it's sealed enough to withstand being submerged for long. So yes, it is water resistant.
Um... Sure? :undecided:
Anywho, this is the spectrum. Nothing special here:
here we have the driver. I haphazardly desoldered that lead by the way, it didn't just come off. It does have reverse-polarity protection, but it draws >400mA when reverse-biased so you better realize your mistake before it overheats. It's a low-side driver, so battery positive makes direct electrical connection to the LED's anode. Regulation takes place between LED cathode and battery negative. The drive current could be changed by adjusting the sense resistance. Feedback voltage is ~50mV.
And a thermal profile under full load after 2 minutes of operation. It will run cooler in the case, since the edges are pressed into the aluminum. See if you can pick out the pass transistor
Low mode is created with PWM which happens at 673Hz at about 30% duty cycle.
Threads EVERYWHERE! It has several metal retaining rings to tightly hold the various components where they should be. There's one for the window, one for the driver, and one to support the pill against the battery case (although that could have been done with machining instead) The reflector screws against the LED to provide pressure through a plastic disc which prevents shorting. Yes, this one has thermal grease.
Lastly: the over-all thermal performance. It does an excellent job, but 3W shouldn't be hard to get rid of anyway. The plastic dome's hot spot here is a decent approximation of the junction temperature, so it is running very cool (these dies supposedly have a max temp of 150C or 300F). This is after the temperature stabilized at about 10 minutes. The temperature does not rise any higher with longer run time.
And the heat distribution along the case:
That about wraps it up. Regulation is adequate, look and feel is good, and heat dissipation is great. Once you get past the listing errors, it's quite a nice light. Is it worth $18 though? Meh, I dunno. I don't have enough experience in the flashlight field to make that call.
equipment used:
Science surplus spectrometer
Tenma 72-6908 power supply
CT-1330B light meter
Fluke 8010M digital multimeter
Valhalla Scientific model 4440 frequency counter
BK Precision model 2125 oscilloscope
FLIR I7 thermal camera
The KX-H02 is available for $18.52 shipped. Stock image:
It has more of a hot spot than the above image suggests. Closer to this:
I guess I'll start by quoting specs and commenting on them.
This is your standard clicky switch. It also protrudes from the back so you cannot stand the light on end.
INCORRECT. There is only high, low, and strobe. Although it is entirely possible they are "hidden" modes and I don't know how to activate them. I prefer this configuration anyways, myself. Measured 6000 lux on high, and 2200 lux on low at one meter.
INCORRECT. You can clearly see from the stock photos that the reflector is (what I believe is called) an "orange peel" type.
I'm not sure why so many people call this a lens. It has no refractive properties. It is simply a window - A flat, circular pane of glass.
Heh, no. It's bright, but not 150 meter bright. I realize this is rather subjective, but 50 might be more reasonable.
Eh... I don't think so. Not unless you're using a state-of-the-art >3600mAh brand name cell, anyway. It draws an amp when in regulation, so 2-3 hours is more typical. It draws 1/3 amp on low, so that should last a good 8 hours or more. Here is a graph of battery voltage versus battery current. And since it is a linear driver, the battery current is the same as the LED current.
Now, according to the cree datasheet, the LED should be dropping 3.7V at 1A. So how is a linear driver staying in regulation at 3.6V? I characterized the LED, and it is quite unique:
So what's going on here? I've never seen a white only drop 3.1V at full current. Is this a special bin they're pulling from? I checked another XRE I had lying around, and it dropped 3.7V as expected, so I'm pretty sure I'm not doing anything wrong. If anyone has any ideas, let me know. :can:
This one has O-rings in the right places. It would be fine with a splash, but I'm not sure it's sealed enough to withstand being submerged for long. So yes, it is water resistant.
Um... Sure? :undecided:
Anywho, this is the spectrum. Nothing special here:
here we have the driver. I haphazardly desoldered that lead by the way, it didn't just come off. It does have reverse-polarity protection, but it draws >400mA when reverse-biased so you better realize your mistake before it overheats. It's a low-side driver, so battery positive makes direct electrical connection to the LED's anode. Regulation takes place between LED cathode and battery negative. The drive current could be changed by adjusting the sense resistance. Feedback voltage is ~50mV.
And a thermal profile under full load after 2 minutes of operation. It will run cooler in the case, since the edges are pressed into the aluminum. See if you can pick out the pass transistor
Low mode is created with PWM which happens at 673Hz at about 30% duty cycle.
Threads EVERYWHERE! It has several metal retaining rings to tightly hold the various components where they should be. There's one for the window, one for the driver, and one to support the pill against the battery case (although that could have been done with machining instead) The reflector screws against the LED to provide pressure through a plastic disc which prevents shorting. Yes, this one has thermal grease.
Lastly: the over-all thermal performance. It does an excellent job, but 3W shouldn't be hard to get rid of anyway. The plastic dome's hot spot here is a decent approximation of the junction temperature, so it is running very cool (these dies supposedly have a max temp of 150C or 300F). This is after the temperature stabilized at about 10 minutes. The temperature does not rise any higher with longer run time.
And the heat distribution along the case:
That about wraps it up. Regulation is adequate, look and feel is good, and heat dissipation is great. Once you get past the listing errors, it's quite a nice light. Is it worth $18 though? Meh, I dunno. I don't have enough experience in the flashlight field to make that call.
equipment used:
Science surplus spectrometer
Tenma 72-6908 power supply
CT-1330B light meter
Fluke 8010M digital multimeter
Valhalla Scientific model 4440 frequency counter
BK Precision model 2125 oscilloscope
FLIR I7 thermal camera
Last edited:
