Electric Bicycle Stalling During Riding

Electric bicycle stalling during riding can be caused by various factors including battery, BMS (Battery Management System), controller, and wiring issues. Below is a summary of symptoms, causes, and solutions.

1. Battery Discharge or Output Drop

▶ Symptoms:

• Suddenly powers off despite remaining battery charge.

• Powers off when accelerating, works briefly after restarting.

• Battery LED indicator blinks or turns off.

▶ Causes:

• Battery aging → instantaneous insufficient output causes power cut.

• Faulty internal cell → a specific cell is over-discharged causing insufficient output.

• Low temperature (winter) → performance drops causing voltage dips.

▶ Solutions:
✅ Measure battery voltage with a multimeter after charging (e.g., 36V battery should be about 42V, 48V battery about 54.6V).
✅ Test ride after full charge.
✅ Check for cell imbalance; replace old batteries if necessary.

2. BMS (Battery Management System) Cut-off

▶ Symptoms:

• Suddenly powers off on uphill or high-speed rides.

• Works fine after charging but powers off again above certain speeds.

▶ Causes:

• Overcurrent protection: BMS cuts off when large current is drawn suddenly.

• Over-discharge protection: battery voltage drops rapidly triggering cutoff.

• Temperature protection: battery overheats, triggering automatic cutoff.

▶ Solutions:
✅ Try resetting BMS by disconnecting the battery for 10–30 minutes and reconnecting.
✅ Consider battery replacement if issue persists after charging.
✅ BMS replacement may be needed (expert service recommended); battery refilling or BMS replacement possible.

3. Controller (Motor Driver) Issues

▶ Symptoms:

• Power turns on but stalls when pedal assist (PAS) or throttle is engaged.

• Battery is fine but power cuts off when increasing speed.

▶ Causes:

• Controller overload → protective circuit triggers due to sudden current spike.

• Internal controller circuit damage → components failure results in no output.

▶ Solutions:
✅ Test by replacing controller if battery voltage is normal.
✅ Inspect wiring for shorts or loose connections; shake wiring to check for power cuts.
✅ Check controller heat sink; cool down if overheated and retest.

4. Wiring and Connector Problems

▶ Symptoms:

• Powers off when hitting bumps or vibrations.

• Power turns on and off intermittently.

• Loose wiring around battery terminals or controller.

▶ Causes:

• Broken or loose wiring → vibration or shock causes power interruption.

• Loose connectors cause momentary power cut.

• Corroded battery terminals hinder current flow.

▶ Solutions:
✅ Inspect and clean battery connectors, then reconnect securely.
✅ Shake wiring to detect power loss points.
✅ Repair or replace wiring if damaged or old.