SEEKING A VERY SPECIAL PSU: Instead of having to hardwire a 700W DC to AC power inverter into my vehicle's electrical system and then plug-in the PSU for my ATX sized PC into that, has ANY company come up with a special PSU that can be direct wired into a vehicle's 12VDC system and therefore eliminate the power inverter altogether???
It seems like a huge waste to go from DC to AC and then back to DC for the PC to use. Plus, the power inverter has a loud fan running when it is converting that much wattage. I believe that a PSU supplies DC voltages of only 12, 5, and 3.3, right?
OR, is there a documented way to "hack" an ATX PSU such that it can be fed 12VDC directly from the vehicle's electrical system? And, it would safely get enough current since it would be hardwired into the vehicle's 12VDC system (ie via proper gauge wiring). This means NOT giving it 12VDC from something wimpy like a cigarette lighter jack.
If not I need a few more details and I will have a solution, if you have a old step up step down inverter then you could wire that as well, but depending on the voltage it would be large and heavy. Also search by toroidal inverters in google. That is what a step up step down is technically called
if you're handy with soldering, you can just purchase some switching power supplies that would go from 12V down to 5V and 3.3V, but you'll likely pay close to $100 each. the benefit is that they can handle enough power and not waste much of it.
plan B is to use old-school voltage regulators to bring the 12V down to 5V and 3.3V but then you'll be generating heat as whatever current the 5V circuits need also flows through the 12V-to-5V regulator, causing it to heat up. this solution is cheap and easy, but horribly inefficient.
next you have load regulation - the 5V and 3.3V stuff should be fine since it would go through a regulator, but the 12V stuff would be nearly directly from the car's alternator and that's not a terribly clean signal - might cause a fair bit of issues.
and lastly, i'm not sure if there's any extensive circuitry that a normal ATX power supply has to RECEIVE control signals from the motherboard. this is something that your car's system obviously doesn't have, so you may need to build-in that feature as well.
bottom line - yes it does suck to go from DC to AC to DC again, but it's likely the safest way for your machine and requires no work on your part.