Say I wanted to fire up a system that wasn't in a car, would I charge and use a car battery for a short amount of time, or would I be able to find a AC -> DC inverter? If so, would it actually be able to produce power enough needed for an amp? (300RMS)
Just curious.
-Mike

Been asked so many times maybe it should be a sticky.

300 rms is a baby amp, so you need a power supply that will do 15 amps @ 12 volts. A heavy duty computer power supply wil do that.

I'd use a car battery and a charger.

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Might want to look at a Computer power supply. For $119 you can get one that does 60A at 12 volts.

Click here.

From that page:
"DC Output
Output:

+5V @ 30A
+12V @ 60A
-12V @ 0.8A
+3.3V @ 24A"

I've seen it and have done it my self. Not with that power supply, but with cheapo ones ripped out of a dead computer. I've also used a power supply from a VCR too.

Look at this one. $70 and it has two 12v rails rated at 20A each.
Click here.

This is how you turn on one of those with out a computer:
Click Here.

Wouldn't need to buy a PSU. I'm a computer guy.. have built all my own computers to date. As such I have maybe one or two lying around. Aren't you supposed to use a decent gauge wire to give an amp power though? whereas something from a MOLEX is a little dinky wire.. That supply rated for 60A is not supposed to go to one molex, but to a whole computer with a lot of much less power-requiring but many parts.

I know that the green wire on the Mobo connector bridged to ground will let the power supply actually work, but beyond that I dont know how to go about hooking it up. ATM I have a spare car battery charging in my garage =P. The charger can output continuous 10A, which could be enough to sustain the battery for a while.

Could also use a radioshack capacitor if using a battery? Would that not save the battery a bit of load?
-Mike

Your right. What I would do is take a few strands of wire (meaning the ones with 5(or so) molex connectors on it. Should be 3-4 of them) take the 12v and ground wires and make 2 large wires(parallel like). Shouldn't be a problem as with a single rail PSU, the 12v wires would come all from the same spot.

quick google gave me this:
Here.

Interesting. I suppose I will have to give this a try. Am almost done building a box for my subs, and will not have my hands on any comps or amp for them till this weekend. This leaves me with my home stereo, and if i get the subs hooked up, a whole lot of kick for my house. Hehe
-Mike