In recent years, due to the rapid development of lithium batteries, many portable products use voltage measurements to estimate the remaining battery power, but the relationship between battery voltage and remaining power will change with the discharge rate, temperature, and battery aging. Use this The error rate of this method can reach up to 50%. As the market's demand for longer-lasting products continues to increase, more precise solutions are required when designing. Using the smart fuel gauge IC to measure the amount of power charged or consumed by the battery will be able to provide a more precise battery capacity estimate within a wide range of application power levels.