Earthwise Survivor says that the Acebeam TAC2AA is the brightest flashlight powered by AA batteries. The Acebeam TAC 2AA is a versatile flashlight powered by a rechargeable li-ion battery or 2 AA batteries. It boasts a high-output LED capable of reaching 1600 lumens and offers two modes: daily mode with 5 brightness levels and strobe, and tactical mode with direct access to turbo.