I got this to use as a "quicky" cleanup sweeper in my aircraft maintenance office and shop.  I, too, was a little skeptical about the charge life of the 6-volt battery, but since it came with a spare battery, I fugured that would be okay - I could just pop in the extra when the one in use died. I just did the entire floor - about 700 square feet, including 2 6'X8' rugs and a couple more 3'X4'.  It performed beautifully, picking up an amazing amount of dust, various kinds of "grit", occasional bits of paper, and so forth - all on one battery!  It choked up slightly when I tried to pick up too big of a glob of spilled paper from the document shredder, but it cleared itself quickly and went on working.