A point-of-sale (POS) device includes a processor, a battery, a transaction object reader, a printer with a printer controller, and optionally a temperature sensor. The processor determines a present power discharge capability rate of the battery, optionally based on a temperature measured by the temperature sensor. The processor also calculates a first estimated power draw rate based on a first setting value for at least one of the components of the POS device, such as the printer. If the first estimated power draw rate is dangerously close to the present power discharge capability rate of the battery, a second estimated power draw rate is calculated based on a second setting value for the one or more components. If the second estimated power draw rate is no longer dangerously close to the present power discharge capability rate of the battery, the components are set to the second settings value.