I'm not sure how long it will last on a battery, but from what I've read you should be able to get a couple days out of it. I actually had to hook it up to a battery last night because where my box was located flooded out yesterday and trashed my power supply. My trees were running good the past 2 days like I said my laterals were full of sap. You guys still think that they just aren't running enough to get it going to the mainline?