Battery Cell Balancing Calculator

Calculate cell balancing requirements for series-connected Li-ion battery packs and balancing time estimates.

Input Parameters

Results

--
Nominal Pack Voltage
V
--
Imbalance Energy
Wh
--
Balance Time Needed
hours
--
Heat from Balancing
W
Note: Cell imbalance grows over time from manufacturing variation, temperature gradients, and aging differences. Passive balancing bleeds excess charge as heat. Active balancing transfers charge between cells for higher efficiency but greater complexity.

Reference

Pack Voltage = N_cells × 3.7V (nominal) Charge Imbalance ≈ ΔmV / 50 × 1 Ah (NMC slope) Imbalance Energy = Charge × 3.7V × N_cells Balance Time = Charge Imbalance / Balance Current Heat = N_cells × I_bal² × R_bleed