Prompted by a reader’s request, I went searching for the brightest flashlight powered by AA batteries. The Fenix TK41 was the winner by far:
Fenix TK41 860 Lumen Flashlight
The Fenix TK-41 U2, which shines at 860 lumens, is the brightest flashlight that runs on AA batteries. It uses eight AA batteries, and these can be rechargeable NiMH or alkaline AAs. The TK41 produces four brightness levels, the lowest (10 lumens) allows the flashlight to run for up to 240 hours.
The Fenix TK-41 U2, is available from Amazon for about $111.
4Sevens Quark “X” AA² Tactical Flashlight
Another bright flashlight is the 4Sevens Quark “X” AA² Tactical Flashlight which produces a remarkable 280 lumens on it’s max setting, and it measures just 5.8 inches in length.
The exact runtime specifications: 24 lumens for 20 hours, 115 lumens for 2.5 hours, and 280 lumens for 1.6 hours.
4Seven flashlights are constructed very well, and they come with a 10 year warranty.
Of course, I recommend powering this flashlight with low-discharge rechargeable AA batteries.