Systems and methods for monitoring the state of charge of a battery of a vehicle are provided. A battery monitor having a processor and a memory is configured to monitor an operating voltage and a loaded voltage of the battery. An electric power steering system is configured to be supplied with power from the battery. The battery monitor is configured to calculate a voltage drop between the operating voltage and the loaded voltage when the battery is under load from the electric power steering system. The battery monitor compares the voltage drop to a predetermined voltage drop and determines that the state of charge of the battery is low when the voltage drop is greater than or equal to the predetermined voltage drop. The battery monitor instructs the electric power steering system to operate in a limited state when the state of charge of the battery is low.