An auto DC adapter has a cigarette lighter input plug on one end that is plugged into the cigarette lighter receptacle and on the other a special output connector that is plugged into the laptop's power receptacle. Although recent P4 laptops have higher and higher power requirements, auto batteries have the capacity to supply the necessary output for the PC.

ASUS
    Asus Eee PC 1008P,
    Asus Eee PC 1015PED,
    Asus Eee PC 1101HGO,
    Asus Eee PC 1201

    Asus Eee PC 1005HA Series
        Eee PC 1005HA, Eee PC 1005HAB,
        Eee PC 1005HA-E, Eee PC 1005HA-H,
        Eee PC 1005HA-M, Eee PC 1005HA-P,
        Eee PC 1005HA-V

    Asus Eee PC 1008HA Series
        Eee PC 1008HA

    Asus Eee PC 1101HA Series
        Eee PC 1101HA

    Asus Eee PC 1102HA Series
        Eee PC 1102HA

    Asus Eee PC 1104HA Series
        Eee PC 1104HA

    Asus Eee PC 1106HA Series
        Eee PC 1106HA

    Asus Eee PC 1108HA Series
        Eee PC 1108HA

    Asus Eee PC 1110HA Series
        Eee PC 1110HA