Are you talking about it simply being inconvenient in industrial use, or some other factor?
Mostly about the inconvenience of replacing batteries once in a while.
Are you talking about it simply being inconvenient in industrial use, or some other factor?
There are a few 2xAA headlamps. The Fenix HL30 and HL35 are examples.
It's more common, however, when 3xAAA or 1xAA are not powerful enough, to jump up to 1x18650.