Use a power calculator to determine whether or not your system will max out a dc-dc controller. Opus has a 250 W in the MP3 store.
I've been running a p3 500 laptop for a couple years now and have finally hit the wall with how far I can mod it. It started out as a compaq armada 1750 p2 366. I have a p3 500 running it with pcmia cards (usb2) and maxed out a 196 ram. The performance is no longer acceptable now that I have switched to the LSX void skin.
I'm going to be switching to a dell gx 260 p4 I have lying around.
I originally went laptop due to the power management versatility. It was powered from a laptop cigarette light adapter wired permanently inot the car. I a realy set sup to turn off the car power to the adapter so that I could run into the garage (or where ever) with the car off and the laptop woud continue to run on battery power until I came back out to start the car. I just set the power options in xp to shutdown after about 20 mins on battery power. Saved me shutting the computer on and off when paying for gas, running into the house, store, etc. I could also press the switch on the dash to shut down the laptop and turn the car off right away as the laptop battery power kept it going long enough to complete the proper shutdown.
The p4 is going to draw alot of power, so much that I don't think that the power supplies with shut down/start up controllers will provide enough juice.
Which means I'm probably stuck with using an inveter to power the pc.
Is there a way I can get the pc to power up and down like I did with the laptop if I have to go with an inverter? The power for the inverter will be setup with a relay that will power it on and off with the key position (can't have it running the battery dry overnight). I already have a 1000w inverter hooked up to allow running other ac powered items when used in-car.