what do you think accounts for this difference in efficiency?

[leon2245]

Xp-g R4 vs. xp-g R5, & emitter(?) vs. "out the front" lumens, but can that alone account for almost twice the runtime? If so, then the jetbeam's "daily mode" is really only ~2/3 of what's claimed? Or are you really getting that much more runtime at such a similar output (looking at these two similar modes only)?

 

[BobG]

More likely it is the method of testing. The quark mini is probably measuring runtime down to 50% of initial brightness whereas the E3S may be using the ANSI standard methodology which measures runtime down to 10% of initial figure. Thus the quark after 8 hours is putting out 12.5 lumens while the E3S after 15 hours is down to 2.3 lumens.

 

[leon2245]

Thanks BobG that would explain it.

It'd just be great to know if it were that & initial outputs were actually similar between the two lights, or if for instance the e3s' daily mode is really more like 12 lumens because of the OTF vs. not rating, & it really does get all that (constant) runtime. Because after seeing the shape of their claimed runtime curve, which is depicted as flat as a board until the very end where it drops straight down like a cliff, it didn't look like there was even much to measure beyond that point!

 

[B0wz3r]

It could also be differences in the driver. The Qmini has a driver that's capable of accepting power up to 3v, which IIRC means it will be less efficient to be able to handle the wider range of voltage. Look at something like an SC51 which does 200 lumens OTF but only on a 1.2 - 1.7v cell; 14500 is not supported.