Thread: Laptop PSU = 12V?

Hi
I want to create a carputer to play MP3s. I have a spare laptop with a broken screen, so that's a good start. I was wondering if I need a new power supply, or whether I can use the existing one. The connection from the mains has the usual box inline (I'm assuming it's a transformer), and it says on the back:

AC Input 100-240V ~1.2A Max. 50-60Hz
Fuse rating F2/250V
DC Output 14-22V 45W max
Or 8-20V 2.2A
For indoor use only etc etc.

The range of voltages is quite high, but they seem in the right sort of range. How can I find out whether i's safe to just wire up the car battery as a power supply?
Cheers
Duncan