a recursive algorithm is provided for adaptive multi - parameter regression enhanced with forgetting factors unique to each regressed parameter . applications of this algorithm can include lead acid batteries , nickel - metal hydride batteries , and lithium - ion batteries , among others . a control algorithm is presented , having an arbitrary number of model parameters , each having its own time - weighting factor . a method to determine optimal values for the time - weighting factors is included , to give greater effect to recently obtained data for the determination of a system &# 39 ; s state . a methodology of weighted recursive least squares is employed , wherein the time weighting corresponds to the exponential - forgetting formalism . the derived mathematical result does not involve matrix inversion , and the method is iterative , i . e . each parameter is regressed individually at every time step .