I have a friend who's getting married this summer. It's an outdoor service in a park far away from any electrical service. However, they do expect ~100 people and would like sound amplification for people speaking, and for the musical components of the service and I offered to do the sound. So... I started looking into battery-supplied portable power units (a gas-generator would be a total no-go as it would be too smelly and noisy). I think something along the lines of the following would do the trick: Amazon.com: Schumacher PP-2200 Portable Outdoor Power Unit: Automotive Amazon.com: Duracell DPP-600HD Powerpack 600 Jump Starter & Emergency Power Source with Radio: Automotive But before I commit to one of these, does anyone have any advice to offer? Am I on the right track or barking up the wrong tree? Note that the only load will be either my Yamaha StagePas300 (includes 8in speaker cabs) or EMX312 powered mixer (into a pair of 8Ohm, 12in cabs), which peak out at 300 and 600 Watts respectively (although we won't be pushing them anywhere near that hard). Inputs will be 4(+/-) dynamic mics and maybe DI'd e-acoustic guitar and maybe DI'd electric bass. I'm thinking 1hr of up-time should be more than enough. A quick back-of-the-envelope calculation makes me think I'd need at most 1-2Ah @ 120V, which roughly translates to 10-20Ah @ 12V. (both units above advertise >20Ah batteries, so I think I'm good).