Is this a stupid question??
About powersupply, we all know that building you're own PSU is one hell of a job. Making consistent voltages from a 12 V car-battery to computer needed voltages.
I've got (and maybe a dumb one )question. Why do we need 12V. For the harddisk and for a cd-rom! Okay, let's say I've got a notebook harddisk and cdrom-player. Both of them work with 5 V.
Guess my question is, are there any other devices that need 12V.
If not, in that case making 5V from car-battery would be less complex.
Correct me if I'm wrong.