I was using a TV/DVD combo that I replace the brick with a 12v cord, worked fine charging or not. Now my Satellite system is 120v so I went back to 120v for both.
What I wanted to add is that just because a brick or wall wart says it puts out 12v doesn't mean it puts out exactly 12v. I have boxes of them that I'll pull from for small projects like testing LEDs and I have to test each to find out what it really puts out. Often they are well above the stated output and not by just a volt or two. One wart rated at 12v put out over 17v and I used it to see if the eBay LEDS would be damaged at higher voltages. They were not.
One thing about going 12v is you don't have to worry about how clean your inverter power is and save a lot not needing a psw unit.