Just want to warn friends here that this method is very risky. Car battery lines carry a lot of high voltage surges, that's why automobile rated regulators have to tolerate more than 48V input voltage. I've seen damages due to the surges on electronic devices, thus I can confirm the requirement is not over kill.

Quote Originally Posted by Frederuco View Post

For a car charger, I took a USB power plug, ripped out the components on the circuit board and direct wired the 12 VDC straight through with a 1.5 Amp fuse.

Also the wall wart is rated for 15 VDC and 1.2 Amps.