12 volt battery as power source

It seems that battery powered devices could eliminate many issues caused by bad wiring, power grid inconsistancies, contamination from appliances, dimmers, etc. That said does anyone think that a 12v deep cell battery hooked up to a 110ac power inverter or similar set up could be a good thing in a power efficient set up?

deep cycle battery:

12v dc to 110v ac converter:
Well running off of battery is good. Running off a power inverter is not. The ac that comes out is worse than what comes out of your wall. Both of my amps, my turntable, and phono stage run off of battery (but all were designed that way), Digital is next. No expensive power cords, no power filtration, no waiting for "magic time"
I configured a 12v battery power supply for my DAC and let me tell you about the noise floor - what noise floor! Infinitely better than the wallwart ps it came with. Not sure about other gear's battery applications but one of the side benefits of using a battery for a DAC is you don't return any of the digital "noise" back into your power sources via a power cord. Many people like to isolate their digital gear from other components and do so in a variety of ways and this is just another one...
Twl (and others) have written a lot about this topic, check out the Audiogon archives.
I'm actually trying to design power supplies that use several battery sources(car batteries) to provide a sufficient collector(or plate) DC voltages to preamps with recharge trigger that will turn on the charge voltage whenever the work voltage drop bellow tolerance.

Designing such PS for large poweramps may be very and very challenging especially if you want to keep an internal PS resistance bellow 8Ohms or number of such batteries should be enormous along with giant size electrolytics.
I use 12vdc batteries for most of my system, and it works very well indeed, as long as the gear is designed to work that way.

You can use a power inverter to power your AC devices from a battery, but you have to get the right kind of inverter that doesn't make noise on the line. Studer Innotek "pure sine wave" inverters will work great with no noise, and I know this because I use one to power my preamp.

As with anything else, you have to know what you are doing,if you are going to make something like this work right.