this feeder saved me numerous times, schedule runs perfectly, portions come out exact (I did measure them from my cats actual food bag measurements), it is fairly easy to set up and figure out.. a couple semi cons, make sure you have a couple days or a week possible for your pet to get used to it and make sure the feedings are timed how you want them to be and yes it does run on batteries. I can usually get 3 meals a day and over 120 meals out of the large feeder. I love this and helps me a TON when we vacation, out of town for a weekend, or just simply out and about. :)