Determining longevity of batteries using depth of discharge

A system comprising:

• at least one electrode configured to deliver electrical stimulation to a patient;
• and
• a device comprising:
• a non-rechargeable battery that is one of a population of non-rechargeable batteries, wherein the device does not comprise the population of non-rechargeable batteries, and wherein one or more non-rechargeable batteries of the population of non-rechargeable batteries have differences in battery capacity;
• a sensor configured to measure a battery voltage of the non-rechargeable battery;
• a memory configured to store a battery voltage threshold derived from a shared voltage magnitude, each of the non-rechargeable batteries in the population having a characteristic to converge at the shared voltage magnitude prior to end of service life and each having a same estimated percent depth of discharge (% DoD) at the shared voltage magnitude;
• processing circuitry coupled to the memory, the processing circuitry configured to:
• deliver one or more electrical stimulation signals to the patient;
• calculate an amount of time remaining before the end of service life of the non-rechargeable battery, wherein the calculation is based on receiving an indication from the sensor that the measured battery voltage satisfies the battery voltage threshold, and a usage rate;
• and
• output an elective replacement indicator (ERI) based on the calculation.

A method for operating a battery powered medical device, the method comprising:

• receiving, from a sensor operatively coupled to a non-rechargeable battery of the battery powered medical device, a battery voltage of the non-rechargeable battery, wherein the non-rechargeable battery is one of a population of non-rechargeable batteries, wherein the battery powered medical device does not comprise the population of non-rechargeable, and wherein one or more non-rechargeable batteries of the population of non-rechargeable batteries have differences battery capacity;
• comparing, by processing circuitry, the received battery voltage to a battery voltage threshold stored at a memory operatively coupled to the processing circuitry,
• wherein the battery voltage threshold is derived from a shared voltage magnitude,
• each of the non-rechargeable batteries in the population having a characteristic for the received battery voltage to converge at the shared voltage magnitude prior to end of service life and each having a same estimated percent depth of discharge (% DoD) at the shared voltage magnitude;
• in response to determining that the received battery voltage satisfies the battery voltage threshold, calculating, by the processing circuitry, an amount of time remaining before the end of service life of the non-rechargeable battery, wherein the calculation is based on the estimated percent depth of discharge (% DoD) at the shared voltage magnitude and a usage rate of electrical energy output by the non-rechargeable battery;
• and
• outputting, by the processing circuitry, an elective replacement indicator (ERI) based on the calculation.

An implantable medical device (IMD), the IMD comprising:

• processing circuitry operatively coupled to a memory;
• a non-rechargeable battery that is one of a population of non-rechargeable batteries, wherein the IMD does not comprise the population of non-rechargeable batteries, and wherein one or more non-rechargeable batteries of the population of non-rechargeable batteries have differences in battery capacity;
• and
• a sensor, operatively coupled to the processing circuitry, the sensor configured to measure a battery voltage of the non-rechargeable battery,
• wherein the memory is configured to store a battery voltage threshold based on a shared voltage magnitude, each of the non-rechargeable batteries in the population having a characteristic to converge at the shared voltage magnitude prior to end of service life and each having a same estimated percent depth of discharge (% DoD) at the shared voltage magnitude, and wherein the shared voltage magnitude is less than a voltage magnitude associated with a beginning of life of the non-rechargeable battery and greater than a voltage magnitude associated with end of service life;
• and
• wherein the processing circuitry is configured to:
• calculate an amount of time remaining before the end of service life of the non-rechargeable battery, wherein the calculation is based on:
• receiving an indication from the sensor that the measured battery voltage satisfies the battery voltage threshold, and
• a usage rate of electrical energy output by the non-rechargeable battery;
• and
• output an elective replacement indicator (ERI) based on the calculation.