A battery charger controller is configured to add a compensation current in the feedback control loop such that the output voltage varies with the output current to compensate charging cable voltage drop. In some embodiments, the output voltage is also proportional to a compensation resistor. Therefore, cable voltage drop compensation can be adjusted using a resistor that is external to the controller IC. The external resistor may be one of the feedback resistors connected at a voltage feedback pin. In another embodiment, the adjustable resistor is the resistor between the feedback resistors and the voltage feedback pin. In still another embodiment, the adjustable resistor is the resistor in parallel with a compensation capacitor. In embodiments of the invention, adjusting the resistance of the external compensation resistor can change the voltage drop compensation and allow the power supply to meet requirements of different charging cable applications.