More proof that Batteroo significantly extends battery life....
https://youtu.be/x62rhxWfmgk
I don't know, the flashlight with the Batteroo sleeve looks brighter from the beginning. Let's do some forensics
I downloaded the video with this online tool:
https://www.onlinevideoconverter.comThen I opened it in Apple Quicktime, which is a nice program to do a frame-by-frame analysis: with left cursor key you can go one frame back and right cursor key one frame forward. In the left bottom corner you can switch between time and frame display. You can see that he has a hard time to move the beam of the right lamp with the sleeve so that it results in the same intensity as the left lamp. Max intensity without the sleeve is 299 lux:
And on the right side it is goes up to 456 lux, if I didn't miss a frame:
Could be because of the crappy reflector in the lamp that there are brighter spots, but for me it looks like the total light output (lumen) of the right lamp is higher, so the flashlight without the sleeve might use partially discharged batteries (at 1:14 in the video, frame 2226, the person was not in the video, they could have just turned on the lamp without the sleeves for some time). You really should not measure lux at a small point, but the lumen of the lamps, which might be more difficult.
But even if they didn't manipulate it, it doesn't look that much worse in the end without the sleeve, if you ignore the numbers in the lux meters and just look at the image:
They don't tell the model and brand of the flashlights, which would be nice to verify the results.