Hi Pondwater, and welcome to the forum!
Well that should be a Cree XM-L LED, which would be a good thing. Unfortunately, there's a good chance it's a knock-off.
But there's way more to a light than what LED is in it. Even if that LED is a knock-off, you could still have a decent light. Or not.
The emitter is actually the little square between "XML" and "JH". The part with the printing on it goes by many names, including board, star, pcb, mcpcb, and others. I usually call it a star, for various reasons. It's part of the heatsink system. In some lights it's connected to a brass part called a "pill". The pill conducts heat from the star to the body of the flashlight, whence it is dissipated into your hand or the atmosphere. A better design, at least from a thermal perspective, has the star connected directly to the light body. This is better for two reasons - aluminum has around 4 times the thermal conductivity of brass, and there's one less thermal junction to get in the way.
If any of those parts are poorly designed, or if any of the connections are poor, the heat will not flow easily from the LED to the atmosphere, and the LED will run hot, and have a shortened life.
An XML driven at 3A (max recommended by Cree) generates enough heat that a light has to be somewhat well designed to keep the LED cool and give it a good life. But few small hand-held lights drive the emitter at 3A. Reducing current does several things - it generates less heat, so the thermal design is less critical; it extends battery life; it generates less light.
Which leads us to the driver. The driver has two main functions - it controls the current to the LED (which directly controls brightness); it provides "modes", which include dimming, flashing, SOS, etc. What makes a driver 'good' is highly subjective, but here are some things to consider:
- it does what it claims - modes, efficiency, output current, etc
- reliability
- efficiency
- has the modes you want
- gives you warnings you need
- actual output current vs. LED capability (considering light design and quality)
So do you have a good light? That's largely for you to say.
Because it's a cheap-a** Ch***** light, it's a sure bet that:
- The lumen output is far below what was claimed. But if the light is bright enough for you, who cares about the lumens?
- If efficiency or battery life claims were made, they were certainly overstated. But if battery life is okay for you, who cares?
- Reliability and lifetime are poor. But you lose crap, so... so what?
- It was much cheaper than a comparable light that's well-made. If you lose a lot of crap, that's pretty important.
D
