A method for estimating a battery state of charge may include determining a first estimated state of charge and a first estimated accuracy of the state of charge using a first estimation approach, determining a second estimated state of charge and a second estimated accuracy of the state of charge using a second estimation approach, and estimating the battery state of charge based on the first estimated state of charge, the first estimated accuracy of the state of charge, the second estimated state of charge, and the second estimated accuracy of the state of charge.

A battery management system for tracking a state of charge of a battery including multiple cells including a coulomb counter (CC) estimator and an artificial intelligence (AI) estimator. The CC estimator determines a charge difference over time for tracking changes of a state of charge of each cell and updates a corresponding state of charge value. The AI estimator converts a set of sample values of a cell into an estimated state of charge for calibrating the cell. A controller may periodically invoke the AI estimator to calibrate the state of charge of each cell and to update a corresponding state of charge value. Processing by the AI estimator may be minimized by being used only to calibrate each cell before combined error of the CC estimator reaches a predetermined threshold. AI based calibration may use Long Short-Term Memories and may further incorporate voltage mean and voltage variance over time.

In an example, a battery management system may include a host microcontroller, which may be operated in accordance with a first clock signal; and a first analog front end (AFE) circuit. The first AFE circuit may be operated in accordance with a second clock signal that may be unsynchronized with the first clock signal. The first AFE circuit may also include first digital circuitry to (1) accumulate a first value corresponding to a number of ADC sample cycles of the first ADC, and to (2) accumulate a second value corresponding to the digital output representative of the first battery current for the ADC sample cycles accumulated in the first value. The first AFE circuit may transfer a representation of the first value and a representation of the second value to the host microcontroller in response to a request from the host microcontroller.