Technical Guide for Winter Maintenance of Electric Forklifts

I. Core System Maintenance: Battery and Power Chain

(I) Power Battery Maintenance

1. Charging Environment ControlMaintain the charging area temperature between 5℃-30℃ and avoid direct charging at temperatures below -10℃. If the ambient temperature is below 0℃, move the battery to an insulated area for preheating 2-4 hours in advance. Start the charging process only when the battery temperature rises above 5℃ to prevent gas evolution corrosion and capacity degradation caused by low-temperature charging.
2. Charging Parameter OptimizationAdopt a winter-specific charging curve: increase the charging voltage by 5%-8% (e.g., adjust the standard 48V to 50.4V-51.8V) and maintain the charging current at 0.1C-0.2C (C = battery rated capacity). Extend the constant current charging phase to ensure balanced cell voltages reach 3.65V-3.7V (lithium-ion batteries) or 2.35V-2.4V (lead-acid batteries).
3. Capacity Management StrategyThe actual available battery capacity decreases by 15%-30% in winter (capacity declines by approximately 8%-12% for every 10℃ temperature ｄｒｏｐ). Adjust operation plans by shortening single-operation duration by 20%-30% and avoid deep discharge (remaining capacity ≥20%). Charge immediately after daily operation and maintain float charging for 1-2 hours post-full charge to compensate for cell voltage differences.
4. Battery Physical Protection
   • Inspect the battery case sealing to prevent short circuits from rain/snow infiltration.
   • Clean oxides and dust from battery terminals, apply special conductive paste (thickness: 0.1-0.2mm), and tighten terminal bolts to the manufacturer’s specified torque (typically 8-12N・m).
   • For lead-acid batteries, replenish distilled water to the liquid level mark; never add electrolyte or tap water.

(II) Motor and Electronic Control System Maintenance

1. Motor Inspection and Maintenance
   • Clean dust, ice, and snow from the motor housing; inspect the cooling fan operation to ensure unobstructed air ducts.
   • Measure motor winding insulation resistance with a 500V megohmmeter (resistance ≥1MΩ; perform drying if below standard).
   • Check motor bearing lubrication and replenish winter-specific grease (temperature range: -30℃-120℃) to ensure smooth, noise-free operation.
2. Electronic Control System Protection
   • Inspect and tighten terminals of controllers, contactors, and fuses to prevent poor contact due to low-temperature metal contraction.
   • Clean dust inside the control box and check the integrity of sealing gaskets to prevent condensation ingress.
   • Conduct power-on tests to verify normal operation of indicators, sensors, and parameters (e.g., motor current, voltage, temperature).

II. Transmission and Travel System Maintenance

(I) Hydraulic System Maintenance

1. Hydraulic Oil Replacement and SelectionReplace hydraulic oil with winter-specific grades (e.g., ISO VG32 or VG46, pour point ≤-25℃). Thoroughly clean the hydraulic tank, filter, and pipelines to remove impurities and old oil residues before replacement. Maintain oil level between tank marks; replenish with the same grade if low—never mix different brands/models.
2. Hydraulic System Leak Detection and Air Purge
   • Inspect seals of pipelines, joints, cylinders, and pumps; ｒｅｐｌａｃｅ leaking seals with low-temperature compatible types.
   • After starting the forklift, repeatedly lift/tilt the forks to purge air from the system and prevent cavitation.
   • ｒｅｐｌａｃｅ hydraulic filters if the pressure difference exceeds 0.3MPa to ensure system cleanliness.
3. Hydraulic Component Maintenance
   • Check hydraulic pump operation and measure outlet pressure (comply with manufacturer specifications, typically 15-20MPa); inspect for pump wear or leakage if pressure is insufficient.
   • Clean rust/debris from cylinder rods and apply anti-rust lubricant to prevent seal wear and leakage.
   • Remove dust/ice from hydraulic radiators to ensure heat dissipation and avoid oil overheating.

(II) Travel System Maintenance

1. Tire Inspection and Replacement
   • For pneumatic tires: Tire pressure drops by 0.07-0.1MPa per 10℃ temperature decrease. Replenish to manufacturer specifications (typically front: 2.5-3.0MPa, rear: 3.0-3.5MPa).
   • ｒｅｐｌａｃｅ tires if tread depth<1.6mm to prevent slipping on icy surfaces.
   • For solid tires: Inspect for cracks or delamination and ｒｅｐｌａｃｅ if damaged.
2. Drive Axle and Steering System Maintenance
   • Replenish or ｒｅｐｌａｃｅ drive axle lubricant with winter-specific gear oil (GL-4/GL-5 grade, viscosity 75W-90, pour point ≤-35℃).
   • Inspect drive axle housings and half-shaft oil seals for leakage; ｒｅｐｌａｃｅ if necessary.
   • Tighten steering linkage joints, replenish winter-compatible power steering fluid, and ensure steering angle compliance (typically 35°-40° left/right).

III. Safety and Auxiliary System Maintenance

(I) Brake System Maintenance

1. Brake Fluid and Pad InspectionReplace brake fluid with winter-specific DOT4 or DOT5.1 (low-temperature fluidity, freezing point ≤-40℃). Fully drain old fluid and flush pipelines with new fluid to remove air. ｒｅｐｌａｃｅ brake pads if thickness<3mm; repair or ｒｅｐｌａｃｅ warped/scratched brake discs. Inspect pipelines for aging/damage and ｒｅｐｌａｃｅ if needed.
2. Brake Performance Testing
   • Conduct no-load and full-load brake tests: No-load braking distance ≤3m, full-load ≤5m (at 30km/h). Adjust brake clearance or inspect for faults if distances exceed standards.
   • Verify parking brake performance: The forklift should remain stationary on a 15° slope; adjust cable tension if slipping occurs.

(II) Auxiliary Safety System Maintenance

1. Lighting and Warning Device InspectionCheck brightness and functionality of headlights, turn signals, brake lights, reverse lights, and marker lights; ｒｅｐｌａｃｅ damaged bulbs/fuses. Clean ice/dust from lenses to ensure visibility. Verify proper operation of reverse buzzers and warning lights.
2. Control Devices and Safety ProtectionLubricate steering wheels, levers, and pedals with low-temperature lubricant for smooth operation. Inspect seatbelt tension and buckle reliability; ｒｅｐｌａｃｅ aging/damaged belts. Clean ice/rust from masts and forks, tighten loose bolts, and ensure chain tension compliance (sag ≤2% of chain length).

IV. Daily Operation and Environmental Adaptation

(I) Startup and Preheating Procedures

1. Pre-Startup Preparation
   • Inspect forklift for damage/leakage and verify tire pressure.
   • Turn on the main power switch and check instrument functionality and battery voltage (lithium-ion: ≥3.2V/cell; lead-acid: ≥2.0V/cell).
   • For long-idle forklifts: Preheat via power supply for 10-15 minutes before starting the motor.
2. Preheating OperationAfter startup, idle for 5-10 minutes. Cycle hydraulic forks up/down and tilt to warm the hydraulic oil. Gradually accelerate to warm the motor and drive axle—avoid sudden acceleration or heavy loads on cold engines to reduce mechanical wear.

(II) Parking and Environmental Protection

1. Parking Location SelectionPark in a dry, ventilated, insulated indoor warehouse (temperature ≥-5℃). Avoid outdoor parking or prolonged exposure to rain, snow, or low temperatures. If indoor parking is unavailable, cover the forklift (especially battery, control box, and hydraulic system) with a waterproof tarp.
2. Long-Term Storage Maintenance
   • For storage exceeding 7 days: Fully charge the battery and disconnect the main power switch.
   • Check battery voltage weekly; recharge if below thresholds (lithium-ion: 3.0V/cell; lead-acid: 1.8V/cell).
   • Start and run the forklift for 15-20 minutes monthly to circulate systems and prevent corrosion/fluid deterioration.

(III) Operational Safety Standards

1. Load and Speed Control
   • Winter load capacity decreases by 5%-10%: Reduce rated load by 10%-20% to avoid motor overload or hydraulic failures.
   • On icy/wet surfaces: Reduce speed by 30%-50% (≤10km/h). Decelerate in advance during turns/braking; avoid sudden stops/turns to prevent skidding or cargo spillage.
2. Environmental Adaptation Measures
   • Clear ice/water from the work area and lay anti-slip mats if necessary.
   • Limit continuous operation in low temperatures to 2 hours; rest for 10-15 minutes to cool the motor, battery, and hydraulic system.
   • Wear cold-protective gear and monitor instrument readings; stop immediately if abnormalities are detected.

V. Maintenance Cycles and Key Performance Indicators

(I) Daily Maintenance (Pre/Post-Operation)

(II) Weekly Maintenance

• Inspect battery terminal cleanliness and tightness.
• Check levels of hydraulic oil, brake fluid, and power steering fluid.
• Clean air and hydraulic filter surfaces.
• Inspect chain tension and lubrication.
• Test braking distance and parking brake performance.
• Verify normal temperatures of the motor and control box.

(III) Monthly Maintenance

• Conduct battery capacity discharge tests; maintain or ｒｅｐｌａｃｅ if capacity degrades by >20%.
• Measure motor winding insulation resistance and inspect bearing lubrication.
• ｒｅｐｌａｃｅ hydraulic and drive axle lubricants (per replacement cycle).
• Fully inspect seals, pipelines, and joints; ｒｅｐｌａｃｅ aging/damaged components.
• Remove rust and apply anti-rust treatment to masts, forks, and structural parts.

(IV) Key Performance Indicator Standards