I thought it was the normal car voltage fluctuations that killed it (up to 14.5 volts) and the egg was just a bad voltage regulator, giving a false feeling of security, but when you use a pre-regulated supply (the 12v psu that you use for the motherboard) then the egg was not needed and actually made the screen dimmer?
Thats how it seems to me from reading up for the past few weeks, but im a noob around here so im probably wrong