The issue is the pump needed to move the water and generate flow would drain the battery life on standard batteries pretty quick. At most your looking at is a few days.
An air pump is such a simple motor and even that will only last a few days so to have a battery operated filter large enough and last long enough to do any good just isn't practical ... IMO
. Even if they were rechargeable, the batteries would probably be as large as the filter.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.