Car Battery as Power Source

Has anyone ever run their stock equipment off a Car battery???
there are two guys who use optima batteries to power some parts of their system. just do a system search for "optima"
Thanx KGTURNER. I checked out those systems. That's in line with what I was thinking but, more complicated. I was just thinking about taking a car battery and connecting an inverter to it and plugging stuff in? I was wondering if this would be akin to using an AC Regenerator - all constraints aside.
I'd want to check the output of the invertor on an oscillascope before going down that route: I wouldn't be surprised if the output of the invertor was nowhere near sinusoidal, possibly much worse than mains AC. You'd have to check it under load, as most AC regenerators measure great until you load them, at which point they measure terribly.

IMO if you have 12v / 24v from a battery the worst thing to do is to convert it back to AC, only to have the power supply in your equipment reconvert it to DC. If you're going to go down the battery route then you should bypass AC altogether (except for the battery charger, which runs when you're not listening). If you google "Red wine audio" that's one example of using 12v batteries.
If you want a true sinusoidal wave, use something like the Xantrex. You are going to have to use a substantial bank of batteries to supply anything over 1000W and you also have to worry about a battery charger (although you can get an inverter and charger in one unit).

Fully concur with Seandtaylor99's entire post.
So, what if I used one of these Pure Sine Wave inverters?

Also, my monoblock amps require 75Watts ea. to operate. So, they don't require much power. Maybe a couple of these inverters with a couple of Optima batteries and I'm in business huh?

Although, from a practical point of view( as opposed to my theoretical and just bored POV) I probably won't realize a material difference in sound if my current electricity is relatively clean when I listen true?

Does anyone know if the PS Audio P300 etc. convert AC to DC and back to AC again within their units?
Here are the inverters I was mentioning:

Unless someone has tried it with your equipment I think you'll have to try it, though I wouldn't be surprised if it sounded worse, not better.

Some powerline filters do regenerate the AC. They tend to be the more expensive ones, as they are really no more than a very high current output power amp. You're effectively using a large power amp to power your system.
Yeah, Seandtaylor99, you're probably right. I'd bet it'd sound the same at best.

Maybe it would have more of an impact on just my tubed phono stage.