How to benchmark battery in flashlight, low temperature performance

pavel

Newly Enlightened
Joined
Dec 19, 2012
Messages
9
I have Zebralight H600... and TrustFire cells from dx.com. TrustFire cells may have been a mistake.

Anyway... they do perform as advertised -- when benchmarking, it gives > 1 hour on 420lm. Not bad. it also has low light modes, like 65lm and 3lm. Using the low-power modes will make battery last significantly longer, right?

Well, not at all. I use it for horseback riding, which means in weather around 0 celsius (freezing). The lamp will behave quite nicely if I switch it on and let it on. It will start in 750lm mode, heat itself, and continue in 420lm, warm, for cca hour. But if I try to extend battery life (or try to be nice to my surroundings) by keeping light down, the temperature will go down, and when I then attempt to use high mode, it will fall to 3lm mode, or even fail completely. Usually it is possible to restart it in 3lm mode after few minutes wait. Ouch. (Switching to 750lm mode is too easy; that usually kills the light when cold. Selecting 420/200/100lm is not possible without going through 750lm mode; that does not help, either).

I have had light failing within 10 minutes -- go low for 10 minutes in cold weather, then switch 750lm mode, then battery trips.

Would some kind of isolation for the light help? Would the results be significantly different with better battery? Is NiMH better than LiIon for this? Is someone doing more realistic benchmarks that cycle maximum mode, but let the light cool down between tests?
 

RI Chevy

Flashlight Enthusiast
Joined
Aug 9, 2011
Messages
3,600
Location
Ocean State
Try some better 18650 batteries first and see if you notice any change. My suggestion would be Panasonic 3400 mAh NCR18650B cells. They are offered both protected and unprotected versions from several different vendors. Also be sure that they are charged with a good, reputable charger to the proper ending voltages (4.15 to 4.2v). I personally would try and start off in the 420LM mode first and bypass the 750LM "turbo" mode due to the heat buildup in the host.
 

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