Are the QAA with 14500 and Q123 with RCR123 the same brightness and runtimes? You did say they have the same circuit and if those batteries have the same voltage they should be the same brightness, right?
More or less - there is always some variability from sample to sample (due to accepted variances in circuit, LED output bin, Vf, etc). And protected 14500s typically have slightly higher capacity than protected RCR, despite being rated the same (typically ~10-30% more in my testing).
At special request, I have now done the 17670 runtime on the QAA head (using the 123-2 battery tube). The result is interesting:
As you can see, you get much longer runtime than RCR or 14500, as expected. But the buck/boost QAA circuit doesn't outperform the buck-only Q123-2 on 17670.
The reason for this appears to be in the regulation - the Q123/QAA head is fully regulated on 1x3.7V Li-ion, but the Q123-2 drops out of regulation and into something approaching direct drive after ~40 mins in the 17670 run. Direct drive is always more efficient that flat-line regulation, so it's not surprising to me that the Q123-2 wins out on 17670.
I plan on buying a QAA-2 tactical..and i plan to use eneloops in them...is eneloops not recommneded for this flashlight? or is it just that the output on max isnt as good as it is with 1 cr123a? and ...is there a chance you can take a picture of the tk20 side by sides standing up on end next to the QAA-2? thank you!
Sorry, I realize I wasn't clear - as others pointed out, I was thinking mainly of the use of alkalines in the lights. The QAA-2 is a very good performer on standard 2xAA ... it's just that relatively speaking, it's not as stellar a performer as it is on 1x3.7V Li-ion. Certainly no qualms about its overall 2xaA performance.
I took the numbers from the review to make some comparison between the Quarks. I thought it may be interesting also for others to look at it gathered if a few tables - I hope it would be ok to put them here: ... I'm not sure how to interpret the measured output values. Is there a linear dependence between the "lightbox max" figure and the lumen output?
No, I'm afraid the lightbox is not really linear. I appreciate that you've put a lot of work in to build your tables, but I don't believe it's possible to justify those efficiency conclusions based on my simple milk carton lightbox.
I don't have have a calibrated integrating sphere to compare, but my experience with Novatac leads me to suspect a simple power relationship fits the relative output data better than a linear one. But again, I believe the box is overly influenced by too many factors to allow you to make absolute efficiency calculations. I thiink it's best to simply accept the runtime data for what it is, and not try to directly compare the lightbox outputs (except as rough visual guides).
interesting.. my runtime graphs were not as flat. how often do you take readings?
Every 30 secs. But more than that, my light sensor is also exquisitively sensitive to even minor fluctuations (i.e. up to 4 sig figs can be reliably obtained). That level of precision contributes to the specficity of the graphs.
In fact, if you check out my
Rogue review, you'll see how well it can discriminate even slight fluctations in the steps (1sec is my the maximum sampling rate of my data-logger). Any deviation from "perfect flat" is very noticeable on the sensor.
Did you notice the flash of somewhat brighter light when changing modes? I though I read that there was a slight pre-flash, but not as bad as some of the older Fenix lights.
Doh, forgot to mention that.
Yes, the pre-flash is there on my samples, as others have reported for theirs. I quickly got used to it, so forgot to mention it (it's also somewhat variable - sometimes it's more noticeable than others). On the whole, it consistently seems to be less noticeable than in my earlier Fenix lights that were susceptible to it.
Do you think you will be getting any of the Q3 5A warm versions to compare runtime and output with these?
Dunno ...