Systems and methods for charging a rechargeable battery device on a marine vessel utilize a rechargeable battery device, a charger charging the battery device, and a control circuit. The control circuit calculates an amount of current that is available to charge the battery device based upon an amount of current that is available from the shore power source and an amount of current that is being drawn from the shore power source by devices other than a voltage charger and limits the amount of current being drawn by the voltage charger to charge the battery device to an amount that is equal to or less than the calculated amount of current that is available to charge the battery device. The control circuit can repeatedly calculate the amount of current that is available to charge the battery device and limit the amount of current being drawn by a voltage charger to charge the battery device to thereby actively adjust an amount of charge applied to the battery device.