as a rule of thumb, i get about 1 hour per 1000mah w/ phantom on, so i can get about 4.5 hrs out of the stock 4600mah one
FWIW tho, mojan at SS told me those start to go bad if not cycled immediately once its in your hands, thats why SS doesnt even have 722/744 batteries onsite, they order them from their source so they dont sit on the shelf and go bad, i bought a cheapie 6000mah one off of ebay and it would never reach full capacity, i get half of what i should out of it