(Covers all modules including battery, controller, motor, and sensor, with tool usage and safety specifications attached)
I. Battery System Fault Troubleshooting
Core Issues: Battery capacity degradation, inability to charge, abnormal voltage| Fault Phenomenon | Troubleshooting Steps & Professional Methods | Recommended Tools |
|---|
| 1. Short battery range | 1. Single-cell internal resistance test: Use an internal resistance tester to test each cell one by one. ｒｅｐｌａｃｅ the cell if the internal resistance of lead-acid batteries exceeds 8mΩ and that of lithium batteries exceeds 50mΩ.2. Capacity test: Conduct a cycle test with a charge-discharge detector. ｒｅｐｌａｃｅ the entire battery pack if capacity degradation exceeds 20%.3. Electrolyte inspection: For lead-acid batteries, add distilled water when the electrolyte level is 6-8mm below the electrode plate; tap water is not allowed. | Internal resistance tester, charge-discharge detector, hydrometer |
| 2. Inability to charge | 1. Charger inspection: Use a multimeter to measure the charger's output voltage (e.g., a 48V battery requires an output of 58-60V); ｒｅｐｌａｃｅ the charger if the voltage is abnormal.2. BMS fault: For lithium batteries, use a dedicated diagnostic tool to read BMS fault codes, then repair or ｒｅｐｌａｃｅ the BMS module.3. Charging circuit inspection: Check if the charging plug and wiring harness are oxidized or open-circuited. Polish the terminals with sandpaper and apply petroleum jelly to prevent oxidation. | Multimeter, BMS diagnostic instrument |
| 3. Sudden voltage ｄｒｏｐ/jump | 1. Single-cell battery short circuit: Use a multimeter to measure the single-cell voltage. A voltage difference exceeding 0.2V (for lead-acid batteries) or 0.1V (for lithium batteries) indicates a faulty cell that needs replacement.2. Loose connections: Tighten the battery terminals with a wrench, ensuring the torque meets the original factory standards (e.g., 10-15N·m for lead-acid battery terminals). | Multimeter, torque wrench |
| 4. Battery overheating | 1. Heat dissipation inspection: Clean the ventilation holes of the battery compartment and ensure the fan operates normally.2. Charging environment: Control the ambient temperature at 25-35℃ during charging; use a cooling fan for auxiliary heat dissipation in high-temperature conditions.3. Overcharge protection: Check if the charger's float voltage is too high (float voltage for lead-acid batteries ≤13.8V per 12V cell) to avoid long-term overcharging. | Infrared thermometer, thermometer |
Professional Tips:- Perform equalization charging (2.4V per cell) for lead-acid batteries quarterly to prevent sulfation.
- Avoid deep discharge of lithium batteries (SOC ≤20%). When parked for a long time, maintain 50% battery capacity and disconnect the negative terminal.
II. Controller System Fault Troubleshooting
Core Issues: Fault code alarms, no motor response, abnormal operation| Fault Phenomenon | Troubleshooting Steps & Professional Methods | Recommended Tools |
|---|
| 1. Controller fault code alarm | 1. Fault code interpretation: Refer to the forklift brand manual to interpret fault codes (e.g., E03 = overcurrent protection, E08 = undervoltage protection).2. Peripheral inspection: For E03, check the motor winding resistance (three-phase difference ≤5%) and whether the circuit is short-circuited; for E08, measure if the total battery voltage is lower than 85% of the rated value.3. Controller replacement: ｒｅｐｌａｃｅ with a controller of the same model for testing to rule out faults of the controller itself. | Multimeter, fault code manual |
| 2. No motor response | 1. Power input: Measure the voltage of the controller's power terminal (e.g., ≥45V for a 48V system); check the battery or circuit if the voltage is abnormal.2. Signal input: Short-circuit the accelerator signal terminal (to simulate an acceleration signal). If the motor starts, the accelerator is faulty and the potentiometer needs replacement.3. Contactor inspection: Use a multimeter to measure the contactor coil resistance (normal range: 20-50Ω); ｒｅｐｌａｃｅ the contactor if the contacts are stuck. | Multimeter, oscilloscope |
| 3. Abnormal driving/lifting | 1. Parameter setting: Use a programmer to check controller parameters (e.g., speed limit, current upper limit), restore default values, and re-commission.2. Temperature protection: Use an infrared thermometer to measure the temperature of the controller's heat sink; stop using if the temperature exceeds 85℃ and check the cooling fan or ambient temperature. | Programmer, infrared thermometer |
Professional Tips:- Anti-static measures are required for controller maintenance. Wear an anti-static wristband before operation and avoid direct contact with the circuit board.
- After replacing the controller, re-match the motor parameters (e.g., motor power, number of poles); otherwise, overcurrent protection may be triggered.
III. Motor System Fault Troubleshooting
Core Issues: Abnormal noise, overheating, insufficient power| Fault Phenomenon | Troubleshooting Steps & Professional Methods | Recommended Tools |
|---|
| 1. Motor abnormal noise | 1. Bearing inspection: Use a stethoscope to listen to the bearing operation sound; ｒｅｐｌａｃｅ the bearing (with the same model as the original factory) if there is a metal friction sound.2. Winding short circuit: Use a multimeter to measure the three-phase winding resistance; if the resistance is unbalanced (difference >5%), the winding is short-circuited, and the motor needs to be rewound or replaced.3. Rotor rubbing: Disassemble the motor to check the gap between the rotor and stator (normal range: 0.2-0.5mm); ｒｅｐｌａｃｅ the rotor if wear is severe. | Stethoscope, multimeter |
| 2. Motor overheating | 1. Load test: Use a clamp meter to measure the operating current; if it exceeds the rated current by more than 10%, it indicates overload, and the load needs to be reduced.2. Heat dissipation inspection: Clean the motor's heat sink and ensure the cooling fan operates normally; reduce the load when the ambient temperature exceeds 35℃.3. Insulation test: Use a megohmmeter to measure the winding-to-ground insulation resistance; repair the insulation layer or ｒｅｐｌａｃｅ the motor if the resistance is lower than 1MΩ. | Clamp meter, megohmmeter |
| 3. Insufficient power | 1. Carbon brush inspection: Disassemble the motor to check carbon brush wear (ｒｅｐｌａｃｅ if the remaining length is <10mm); ensure uniform spring pressure (standard pressure: 15-20N).2. Controller output: Use an oscilloscope to measure the controller's output waveform; if the waveform is abnormal, the controller is faulty and needs repair or replacement. | Spring dynamometer, oscilloscope |
Professional Tips:- After disassembling the motor, re-conduct a dynamic balance test to avoid excessive vibration during operation.
- After replacing the motor, adjust the encoder position (e.g., for permanent magnet synchronous motors) to ensure compatibility with the controller.
IV. Sensor System Fault Troubleshooting
Core Issues: Misoperation judgment, abnormal data, safety interlock failure| Fault Phenomenon | Troubleshooting Steps & Professional Methods | Recommended Tools |
|---|
| 1. Abnormal accelerator signal | 1. Voltage test: Disconnect the accelerator plug and measure the signal terminal voltage (0V at idle, 5V at full acceleration); ｒｅｐｌａｃｅ the accelerator if the voltage is abnormal.2. Linearity inspection: Use a multimeter to slowly press the accelerator pedal; the voltage should rise smoothly. A fluctuation exceeding 0.5V indicates potentiometer wear. | Multimeter |
| 2. False alarm of tilt/height sensor | 1. Zero calibration: Use a dedicated tool to re-calibrate the sensor zero point (e.g., the tilt angle should be 0° when the fork is horizontal).2. Signal interference: Check if the sensor wiring harness shield is grounded; keep it away from high-voltage cables (distance >30cm) to reduce electromagnetic interference. | Inclinometer, oscilloscope |
| 3. Safety interlock failure | 1. Switch test: Use a multimeter to measure the on-off status of the seat switch and emergency stop switch; ｒｅｐｌａｃｅ if the contacts have poor contact.2. Logic inspection: Check if the interlock circuit is short-circuited or open-circuited; test the function after repair (e.g., prohibiting startup when the seat belt is not fastened). | Multimeter |
Professional Tips:- Sensor calibration must be performed on a flat surface to avoid environmental errors.
- After replacing the sensor, reconfigure parameters (e.g., height upper limit, tilt angle threshold) to ensure compatibility with the controller.
V. Electrical System Safety Operation Specifications
High-Voltage Protection
- Disconnect the main battery switch before maintenance and use a voltage tester to confirm no voltage (DC >60V is considered high voltage).
- Wear insulating gloves (with a voltage resistance of 500V or above) and goggles when operating high-voltage components (e.g., motor, controller); do not touch exposed terminals with bare hands.
Fire and Explosion Protection
- Maintain good ventilation during battery charging to avoid hydrogen accumulation (hydrogen concentration >4% may cause explosion); open flames are prohibited.
- If a lithium battery experiences thermal runaway (smoke, bulging), immediately extinguish the fire with a dry powder fire extinguisher and isolate the battery; water is prohibited for extinguishing.
Anti-Static Protection
- Wear an anti-static wristband before touching the circuit board, and use anti-static tweezers for tools to prevent electrostatic breakdown of electronic components.
VI. Preventive Maintenance Recommendations
| Cycle | Maintenance Items | Recommended Tools |
|---|
| Daily | Check battery voltage, controller alarm light, and whether wiring harness connections are loose. | Multimeter |
| Weekly | Clean the battery surface and controller heat sink; check motor carbon brush wear. | Brush, vernier caliper |
| Monthly | Measure the internal resistance of individual battery cells with an internal resistance tester; measure the temperature of the motor/controller with an infrared thermometer. | Internal resistance tester, infrared thermometer |
| Quarterly | ｒｅｐｌａｃｅ the hydraulic oil filter (simultaneously check if the hydraulic system affects electrical components); test the motor insulation resistance. | Megohmmeter |
| Annually | Fully disassemble and inspect the motor bearings and internal capacitors of the controller; conduct a battery capacity test (charge-discharge cycle). | Bearing puller, charge-discharge detector |
Record Management
Fill out the Electrical System Maintenance Record Form for each maintenance, including fault phenomena, test data, replaced components, and operator information, to facilitate traceability and analysis.Through the systematic troubleshooting methods above, the root cause of electrical system faults in electric forklifts can be accurately identified, while high-voltage operation risks are avoided and equipment service life is extended. For complex circuit board repairs (e.g., controller chip-level faults), it is recommended to send the equipment back to the factory for processing to ensure reliability.
