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byd_bms01
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BYD · Electric & Hybrid Cars
Blade Battery Cell Voltage Imbalance
Quick Answer
Error code BYD_BMS01 on your BYD Electric & Hybrid Cars means: Blade Battery Cell Voltage Imbalance. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
BYD-A3BYD-DPBYD-HNBYD-SLBYD-SUBYD-SPBYD-TG
Likely Causes
  1. Uneven aging across Blade Battery cells causing individual cells to reach voltage limits before others
  2. Manufacturing variation in cell capacity amplified over repeated charge-discharge cycles
  3. BMS passive balancing circuit malfunction preventing voltage equalization between cells
  4. Temperature gradient across the battery pack causing cells in warmer zones to cycle faster
  5. Partial short circuit within a cell module reducing its effective capacity relative to neighboring cells
How to Fix It
1
Perform a slow full charge via Level 2 AC charging to allow BMS balancing circuits to equalize cell voltages
2
After full charge, check for BMS-reported minimum and maximum cell voltages in the vehicle diagnostics menu
3
Avoid frequent deep discharges that can amplify imbalance across cell groups
4
Ensure the vehicle software is updated to the latest version which may include improved BMS balancing algorithms
5
Contact BYD service if cell voltage spread exceeds manufacturer threshold after a full balancing charge
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
BMS software update via service tool
Blade Battery cell module (if individual module replacement is required)
BMS diagnostic interface tool
Related Error Codes
BYD_BMS02BYD_BMS03BYD_CHG01BYD_CHG02BYD_CHG03
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