Voltcraft usb car laptop chargers voltcraft smp 125 usb the voltcraft smp 125 usb car charger has been designed to supply devices such as laptops or netbooks with power there are eleven different output voltages to select from the connected loads current consumption must not exceed the maximum output rating of the product power is supplied via the cigarette lighter socket of a vehicle 12 to 138vdc positive pole inside the product features both short circuit and overload protection