Shimano STEPS Battery Charging Faults

Shimano STEPS batteries (BT-E6010, BT-E6001, BT-E8010, BT-E8020, and their BT-E8035/8036 successors) use a dedicated charging protocol managed by the battery BMS. When charging faults occur, the battery LED indicators display error patterns rather than the usual charge level sequence. This guide covers every common Shimano STEPS charging fault and its resolution.

Over-Current Protection Tripped

The battery LED flashes in a fault pattern when the BMS over-current protection trips during charging. This typically happens when the charger delivers an initial current spike — most common with aging chargers or when the battery is connected to the charger while at very low temperature.

Fix

  1. Disconnect the charging cable from the battery.
  2. Press the battery power switch once to reset the BMS protection circuit.
  3. Reconnect the charging cable. Charging should resume normally.
  4. If the over-current protection trips repeatedly, test with a different genuine Shimano charger. Repeated tripping with a known-good charger indicates a BMS fault requiring dealer inspection.

Charging Communication Error

If charging simply does not start — the charger LED stays red or goes to fault mode immediately — the battery BMS is not responding to the charger handshake. Common causes: dirty charge port pins, a damaged charging cable, or a BMS that is in deep-discharge protection.

Fix

  1. Clean the battery charge port with contact cleaner spray and allow to dry.
  2. Inspect the charging cable for damage or bent pins.
  3. Test with a different genuine Shimano charger.
  4. If the battery has been stored discharged for an extended period, it may be in deep-discharge protection. Connect to the charger and leave for 60 minutes without disconnecting — the BMS may recover slowly from deep-discharge mode.

Temperature Cutoff During Charging

Shimano STEPS batteries will not accept charge below 0 degrees C or above 40 degrees C. If the charging environment is outside this range, the BMS blocks charging to protect the cells.

Fix

Move the battery to a room-temperature environment (15 to 25 degrees C) and allow it to reach ambient temperature before attempting to charge. Charging in a garage in winter at below-zero temperatures is a common cause of this fault.