DC-DC Vs Special Car PC Power Supplies
Home computer (normally desktops) uses power supplies from AC (Alternating Current). A car battery provides 12 V DC, which can be utilized to power the Car PC by DC-DC power supply.
High Resolution:Display - up to 1024 x 768 VGA input Lilliput Eby701-np/c/tDC-AC-DC inverter and its usage
An inverter gives AC from the given DC power supply, so that normal low power consuming appliances can be used. However this method is very inefficient as inverter wastes lots of power while converting DC-AC-DC.
The real necessary requirement for Shutdown Controllers
Shutdown Delay
The normal DC-DC converter will not trigger a shutdown pulse and wait rather it will cut the power supply when the Ignition is off. So the Car PC should be shutdown / hibernate / Standby before switching off the ignition. This is troublesome if you are forgetting one day to shutdown and switched off the ignition, chances are the next time when you triggering the ignition the Car PC might be already dead.
Working Voltage DC 10.8-16V DC new! 7 inch touchscreen car home pc vga screen speakersSurvive Engine Cranking
Another biggest disadvantage of just a DC-DC Power supply is it may not survive the engine cranking. It may fluctuate from 6V to 24 V. This is one another way to kill the Car PC.
Basically I was in need of these two characteristics in a car pc, Finally after reading some good forums I found M2-ATX worked me very well