Ok folks - think about this.
Your equipment will need electricity to run, regardless of where it gets it from. Plugging in directly to the wall, it will use an amount or if you plug into a bank of batteries, it will draw the same amount.
If you hook it all up to car batteries it will also need a different current type. DC vs. AC that comes out of your wall, and AC is what your ballast will use.
In both scenarios, the one thing that does NOT change is how much power you need. Plugging it right into the wall is simple, and easiest. Using batteries requires that you convert the power to AC, and then recharge the battery cells (with the power from the wall). You lose some power in the conversion and the recharging process as it is never 100% efficient.
In summary - running your equipment on batteries will not mean you use less power. In fact you will use MORE since you lose the overhead needed to charge the batteries and convert the power. Not to mention the cost of the battery, and the fact that car batteries are not intended for long term and sustained draws. Now unless you are paying a different rate for your power at different times of the day (and even that is a stretch), this makes absolutely no sense to go this route in hopes of saving money.
