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Balancing Module

Source: docs.foxbms.org — Balancing Files: src/app/application/bal/bal.c, bal.h, bal_cfg.h Strategies: bal_strategy_voltage.c, bal_strategy_history.c, bal_strategy_none.c

Strategy 1: Voltage-Based Balancing

  1. Find minimum cell voltage in pack
  2. Balance all cells with voltage > V_min + BAL_GetBalancingThreshold_mV()
  3. When equalization complete, new threshold = V_min + threshold + BAL_HYSTERESIS_mV (prevents oscillation)

Strategy 2: History-Based Balancing (SOC-Based)

  1. Wait for rest period (voltages stabilize)
  2. Convert cell voltages to SOC via lookup table
  3. Convert SOC to DOD: DOD = Capacity × (1 - SOC)
  4. Most discharged cell becomes reference (DOD = 0)
  5. Calculate charge difference for each cell: Charge_diff = DOD_ref - DOD_cell
  6. Balance continuously: every second, I_bal = V_cell / R_balancing
  7. Reduce charge difference by I_bal × 1s each second
  8. Deactivate when charge difference = 0

Requirements: - SLV_BALANCING_RESISTANCE_ohm must match physical balancing resistors - SE_GetStateOfChargeFromVoltage() lookup table must be configured

Strategy 3: No Balancing

Disables all cell equalization.

POSIX Port Status

Balancing logic runs but has nothing to balance — all cells are identical (3700mV). GAP-ANALYSIS GA-10: need per-cell voltage variation (Phase 2 remaining work) to exercise balancing decisions.

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