Questions about swapping L2 U2 with MT-G2

Hello, I am very new for flashlight hobby. I do have few questions about flashlight mod. I have a Chinese diving light with U2 LED and 1x18650 battery. Manufacturer claimed for 800 lumens. Is that possible to make it brighter? How? I look at datasheet of U2 and MT-G2 LED bulb. It seems that G2 has more lm than U2 with the same current. Will swaping U2 with G2 make it brighter? Or is there any easier way to improve the light?

thank you very much,

You would probably want to put a better driver in your flashlight as opposed to trying to put an MT-G2 in it.

You also need to remember that the MT-G2 requires 6V. So you would need a boost driver that can bump up the voltage of 1x18650. Not sure how easy this is going to be to find. Not to mention that even a fairly modestly driven MT-G2 will suck down an 18650 REALLY fast. That’s probably the reason why 1xLi-Ion MT-G2 lights run on a 26650 rather than an 18650 - they really NEED the extra capacity.


THe XML is designed to run on single cell voltages.

THe MT-G2 is designed to run on multi cell voltages.

A boost driver is possible (but not common to run the MT-G2 off a single cell, typically a 26650 cell)

Look to replace your driver as a clean way to get more lumens one can also got Direct Drive (DD) where it is wired like the old time bulb flashlights. (switch, battery, emitter) you will have only full blast availible and it should get hot fast so this is not a good plan for a requirement of long run times.


However if you do this it is recommended that you reflow your emitter onto a Noctigon or Sinkpad star if you want the emitter to last more than a few minutes on high, maybe less.

OP do you have a picture of the light you are working on?

Thanks, now the driver is XM-L2 U2. What driver do you recommend if I need more light? I don’t care much how fast it will draw current as long as it can operates up to 1 hour.


No, that describes the LED.

The “driver” is the circuit board between the LED and the battery.

What you are asking for is probably almost impossible. 1000 lumens requires the battery deliver about 3 amps (more as the battery voltage declines), and the highest capacity 18650 cells that are readily available are about 3500mAh. About 1000 lumens for about an hour is the best you can hope for today. Driving the LED harder will produce more output, but it also takes more current, and the efficiency of LED’s goes down as you increase the drive level. More light output=shorter run time.

thanks for info. :slight_smile:

You could try dedoming the LED if you want more throw distance (and tighter hotspot). Assuming the light has a reflector and is not a flooder. MT-G2 could be more powerful by lumens, but it does not throw as well (lux) in same reflector because of larger surface area.

What light and batteries are you using?

There is a very good chance that the light you have is not putting out even close to 800 lumens right now. It’s not likely that it is. Most manufacturers over-estimate their lumens by a lot. It would help a lot to know what light it is and what battery you are currently using. In many cases simply switching to a high amp battery and doing a simple spring mod will get you more lumens. By spring mod I mean taking a wire or copper mesh and soldering it from the bottom of the spring to the top. The springs often have a lot of resistance. Next cheap fix is heavier wire from the driver to the emitter. If none of this gets you the lumens you are looking for then a new driver is in order and if that new driver is putting out a high amount of amps then the emitter needs to be reflowed onto a copper base. (noctigon or sinkpad).

Chances are you will see a large bump by going with high amp batteries and spring mods. As stated above an MT-G2 will not work because it’s designed for at least two batteries.