SDAA084 April   2026 BQ25856-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2How to Extend the Life of Supercapacitors
    1. 2.1 Effects of Voltage
    2. 2.2 Effects of Current
    3. 2.3 Effects of Temperature
  6. 3Supercapacitor ESR and Capacitance
    1. 3.1 Estimating Capacitor Capacitance and ESR
    2. 3.2 Measuring Supercapacitor Health With The BQ25856-Q1
    3. 3.3 Estimating the Capacitance and ESR in Reverse Mode
  7. 4Summary
  8. 5Appendix - Example MCU Code for the BQ25858-Q1
  9. 6References

2 How to Extend the Life of Supercapacitors

The functional lifespan of a supercapacitor is dependent on the voltage, charging current, mechanical stress, and operating temperature. Many supercapacitor manufacturers determine their capacitors to have reached EOL when the capacitance decreases to 80% of the nominal value or the equivalent series resistance, or ESR, increases to 200% of the nominal value. Check with the manufacturer of each supercapacitor to determine when the supercapacitor has reached EOL.

This application note primarily focuses on how to measure the ESR and capacitance of a supercapacitor. Nevertheless, here are a few areas that can reduce the overall lifespan of supercapacitors and how the BQ2585X-Q1 can be used to mitigate the decreasing life span.