Figured this might be a good forum section to ask. I'm trying to run my home stereo this weekend at the pocono infield without bringing my generator because its too loud. I've already figured out on a online calculator that it would require 420 watts. I can borrow a 600watt inverter from a friend that hardwires to the battery or in my case the 12V bus on my M1008. The M1008 has already been converted to 12V only and has 2 1000ca batteries. I can't find a amp hour rating on them the stickers are gone. The inverter shuts off at 10V I believe. My question is how long can I run without the truck running before it shuts off. Is more info needed? Thanks in advance. As a side note, I was trying to avoid this whole situation by ordering a JVC Kaboom box, but the shipping got messed up and now its not arriving in time.