A method for determining a maximum electrical charge current (i max) or a maximum electrical discharge current (i min) of an energy storage cell, said method comprising the steps of: (a) providing a predetermined upper voltage limit (V max) or lower voltage limit (V min) of the energy storage cell; (b) providing a time horizon (Δt) as a time difference from a present time (t) to a future time (t+Δt); wherein, with a repetition time period (ΔT) different from said time horizon, repeating the following steps: (c) measuring a present voltage level of said energy storage cell; (d) calculating a voltage difference (ΔV) between said present voltage level and said upper voltage limit (V max) or said lower voltage limit (V min); (e) based on said voltage difference, said time horizon, and a RC equivalent circuit model comprising a capacitance and a resistance of the energy storage cell relating an electrical charge current or an electrical discharge current to a respective estimated voltage of said energy storage cell, determining the maximum electrical charge current (i max) or maximum electrical discharge current (i min) of the energy storage cell corresponding to the voltage difference, wherein said maximum electrical charge current or maximum electrical discharge current (i max; i min) is given by: i max, min = Δ v + R 0 i t + v ^ 1 t 1 − e − Δ t R 1 C 1 R 0 + R 1 1 − e − Δ t R 1 C 1, where R 1, C 1, are the resistance, capacitance of the RC equivalent circui model and v̂ 1 is an estimated voltage across said RC equivalent circuit model, R 0 is an internal resistance of said energy storage cell, i is the current through the energy storage cell, and t is time, and wherein Δv for the maximum electrical charge current (i max) is the difference between said upper voltage limit and said measured voltage, and Δv for the maximum electrical discharge current (i min) is the difference between said lower voltage limit and said measured voltage, wherein the respective estimated voltage of said energy storage cell is less than or equal to said upper voltage limit during said time horizon in the case of an electrical charge current or, larger than or equal to said lower voltage limit during said time horizon in the case of an electrical discharge current. (a) providing a predetermined upper voltage limit (V max) or lower voltage limit (V min) of the energy storage cell; (b) providing a time horizon (Δt) as a time difference from a present time (t) to a future time (t+Δt); (c) measuring a present voltage level of said energy storage cell; (d) calculating a voltage difference (ΔV) between said present voltage level and said upper voltage limit (V max) or said lower voltage limit (V min); (e) based on said voltage difference, said time horizon, and a RC equivalent circuit model comprising a capacitance and a resistance of the energy storage cell relating an electrical charge current or an electrical discharge current to a respective estimated voltage of said energy storage cell, determining the maximum electrical charge current (i max) or maximum electrical discharge current (i min) of the energy storage cell corresponding to the voltage difference, where R 1, C 1, are the resistance, capacitance of the RC equivalent circui model and v̂ 1 is an estimated voltage across said RC equivalent circuit model, R 0 is an internal resistance of said energy storage cell, i is the current through the energy storage cell, and t is time, and wherein Δv for the maximum electrical charge current (i max) is the difference between said upper voltage limit and said measured voltage, and Δv for the maximum electrical discharge current (i min) is the difference between said lower voltage limit and said measured voltage, wherein the respective estimated voltage of said energy storage cell is less than or equal to said upper voltage limit during said time horizon in the case of an electrical charge current or, larger than or equal to said lower voltage limit during said time horizon in the case of an electrical discharge current.