Abstract: A power supply system between a power supply and an electrical load uses a plurality of battery modules which may be different in configuration from one another. The system assesses one or more state variables for each battery module to indicate a health status of the battery module. The variable indicative of the health status typically includes: i) a residual ability of the battery module to accept electric charge, ii) a residual capacity of the battery module to hold electric charge, iii) an internal resistance of the battery module, iv) a conductance of the battery module, v) a capacitance of the battery module, vi) a rate of charge of the battery module, vii) a rate of discharge of the battery module under load, or viii) a rate of self-discharge of the battery module. The system then generates unique charging and discharging criteria for each battery module which is specifically derived from the health status of the battery module.