A system and method for externally controlling the charging of a battery powered mobile computing device includes a charging unit configured to be electrically coupled to the mobile computing device to charge a battery therein. The charging unit comprises a charger configured to operate in a first mode to provide a constant charge current to the battery to be charged and to operate in a second mode to provide a constant charge voltage to the battery to be charged and where the switch from the first mode to the second mode occurs when the voltage at the battery a predefined threshold voltage. The charger including an offset compensator configured for applying an offset voltage to the measured output of the charger to maintain the charger in the first mode to compensate for voltage drops between the charger and the battery thereby allowing the battery voltage to reach the threshold voltage.