Power Supply thoughts needed

[jonjonr6]

Thanks everyone,<p>I eventually broke down and looked for the simplest solution. I ended up with a standard ATX power supply running off a DC power invertor (I already have both), and a system board that supports "last power on state" (will boot automatically when the power is reapplied). The unit will have to use Hibernate instead of Standby, but I guess I'll have to make do with that.
Since the power inverter uses .2A even when turned off and no load, I am going to use a Bosch 30A relay tied to keyswitch to remove the 12v when off. I have also incorporated a delayed shutdown with a 556 timer so the unit doesn't hibernate when I run into the store. To keep the inverter powered on after keyswitch is removed, I will diode isolate keyswitch and a 12v output line from the ATX hard drive power legs. The timer relay will time out after 45-60 mins and close the power button loop to shutdown.
Next hurdles... automatic pause/resume. Not that important.