Car Stereos: Wiring my car stereo, inline fuse, power suppy

Question
Hello I have a question for you if you help please.
Recently my stereo went off and only came on randomly after driving a while. I checked the fuses and seemed fine but using my voltmeter i couldn't detect any power from stereo wires, could there be a wiring problem in the ignition somewhere?
So i decided to run a new cable directly from the battery terminal to the stereo, i understand i will have to turn it on and off myself as i've bypassed the ignition, is this generally ok to do? so now the ignition power suppy is useless to me do i run my new power cable to the permenent power at back of stereo or the ignition power(i.e the one which came from ignition?)
Also are the ignition and permenent power the same i.e 12v? which one does the stereo use to function?
If you can help that would be great and appreciate your help.
Thank you.

Answer
Hi Ashley,

The first obvious thing to check is the fuses.  If you've popped a fuse or some fuses, that'll be your issue.

Second, if you choose to stick with a wire direct from the battery, that's fine, but MAKE SURE YOU PUT AN INLINE FUSE ON IT!  You don't want to find out the hard way that a fuse popped because it should have, and being unfused, the new wire causes an electrical fire in your car.

The ignition power power, and the constant power wire are both the exact same in that they both provide 12V to the deck.  The difference between them being that the ignition wire turns off when the car is not on or in accessory.

So with that in mind, you'll want to find another power source to provide the 12V switched for ignition, or run the risk of draining the battery overnight by accidentally forgetting to turn the stereo of.

Options include a cigarette lighter, ignition wires straight from the ignition column, etc.

Justin