Is the KL1-Lux3-4thGen 9V tolerant?

Based on my assumptions that this KL1 follows in the footsteps of previous KL1s, it SHOULD be 9V tolerant, but I'm wondering if anybody else has heard stuff to the contrary. A helpful CPFer pointed out that it's a risk to assume I can just run 2xR123 (8.4V peak) on the new KL1. Good point! /ubbthreads/images/graemlins/smile.gif

In my limited understanding of buck converters, they generally have quite a wide range of voltages, but function best where VIn is closer to Vf. There should be enough tolerance.. or so I hope.

KevinL,
I asked PK this very question and his recall on the upper Vin limit was that it is somewhere in the mid 8 Volts but he was not certain at the time nor did I ever follow up and press for an answer. I did a run time test on the new KL1 with 3x123 and the sucker did get pretty dang warm! My gut feeling is that 2xLi-Ion is probably OK but that 3x123 is perhaps not a good idea on fresh cells. It would be instructive to monitor the voltage drop on 3x123. /ubbthreads/images/graemlins/icon3.gif Sorry I don't have the actual Vin limitations but take this answer for whatever it may be worth.

Don, thanks for the info, it does help.

Sorry if it seems obvious, but how do you measure the voltage drop when the light is running? I know how to measure current (remove tailcap, stick one DMM probe into the battery, one against the conductive rim of the light), but not voltage.

I will .. uhh .. sacrifice my KL1 on 2xR123 /ubbthreads/images/graemlins/wink.gif I'm willing to take the risk to find out. Guilt free lumens sounds good!