Tony, the average car battery is about 48 ampere hours, which means at maximum load, the inverter draws about 9 amps, which translates to about 5 hours before the car battery would go dead with that amount of drain.

Keep in mind, however, that most of us use far less than 1000-watts of power with our full setup. For example, my Bose L1 Compact draws less than 150-watts when cranked up full. A typical mixer draws less than 20-watts. My PSR-S950 only draws 19-watts. So, for me, playing to a crowd of 150 or less ppl, with my full setup, I would draw 169-watts. Therefore, my total drain on the battery would be about 2 amps, which is less than the overhead light in the interior of the car.

Yes, most small motorcycle or tractor batteries would do a great job, though I have never tried using them for outdoors. In locations where I was not able to get the car/van close to the venue, I made a 100-foot long DC cable with heavy-duty battery clamps. I connected the inverter to the opposite end and it worked fine for hours on end, no car start problems - ever. I only used that long cable a couple times, though. Most of the outdoor jobs I performed, which amounted to about a dozen a year, the venue supplied me with 110-volt power.

For me, the biggest stumbling block of performing outdoors were seeing the keyboard's screen and buttons, which is a problem with every manufacturers keyboard I've ever owned. During the last 10 years of my musical career I insisted on some sort of dark colored canopy or gazebo to set up in. All of the restaurants and catered outdoor jobs complied with my request.

Now, when it comes to battery powered gear, most of which is powered with "C" or "D" cell batteries, the life of the batteries has always been quite limited. One of my first Yamaha arranger keyboards had space for 4 D-cell batteries. Usually, the maximum amount of playing time I could count on was about 1-1/2 hours at best before the batteries took a dump. Shortly after that, I purchased an inverter. I also have an inverter on my boat, which runs the TV, Microwave oven and a couple fans. The microwave sucks down a battery pretty quick because it draws 1,100-watts. The TV, however, only draws about 45-watts and it is a 21-inch LED TV.

Hope this answers some of your questions,

Gary