Nitecore TM06 (4xXM-L2 U2, 4x18650) review: RUNTIMES, BEAMSHOTS, VIDEO and more!


Newly Enlightened
Jan 25, 2013
I received my TM06 in December and have since noticed that two of the cells discharge to different voltages than the other two. The last time I removed them to charge them there was a difference of about 0.2 volts. This time; however, two of them were 4.04 volts and the other two were 3.58 volts, a difference of 0.46 volts. I examined the internals of the flashlight without the cells inserted, used an ohm meter, and determined that the four cells are in series with a center tap between the four. If two of the cells are inserted on one side of the center tap and the flashlight is assembled, nothing happens when the tail cap switch or side switch are activated. If the cells are then moved to the other side of the center tap, the side switch blue LED displays the voltage of one of cells by blinking, and then it flashes as a beacon as it normally does. If the tail cap switch is then turned on, the blue light blinks rapidly and the flashlight does not light. The blue LED reverts to its previous condition when the tail cap switch is turned back off. The blinking switch LED can be turned on and off as normally by depressing the side switch.

This leads me to the conclusion that the blue flashing LED and the electronics/standby circuits are driven off of only two of the cells, and the front LEDs are driven off all four of the cells. In my opinion, this is poor circuit design because leaving the blue LED flashing will drain two of the cells while the other two remain almost fully charged. This is not good, as the four cells will be discharged unevenly by design.

So, now I will not be using the standby blue flashing LED at all to help prevent the uneven discharging of the cells. It is too much trouble to lock out all functions by unscrewing the tail cap three complete turns.

Same, here, after 2-3 Month (forgot to lockout) 2 of the cells where discharged dramatically.