I. Basic Concept Differentiation

Rated Load: The maximum allowable lifting capacity of a forklift under standard operating conditions (at the standard load centre distance).The load centre distance is a critical supporting parameter. Most lithium-ion forklifts adopt a standard load centre of 500 mm. Increasing mast lifting height, attachment fitting, and eccentric load placement will reduce the actual effective load capacity — this is the most frequently overlooked pain point in equipment selection.Core Logic: Do not rely solely on the nominal tonnage. The actual effective load capacity must be calculated. Load requirements determine the complete vehicle architecture, battery configuration, hydraulic system, wheel assembly and frame grade.

II. Six Dimensions How Load Capacity Determines Lithium-ion Forklift Selection

1. Tonnage Class Selection (Most Direct Basis)

1. Light Load (1.0 t ~ 1.8 t Lithium-ion Forklifts)Application: Narrow-aisle warehousing, e-commerce sorting, light cartons, plastic pallets.Selection Constraints: Prioritise 3-wheel lithium-ion forklifts for space-restricted environments. For low continuous load, standard lithium iron phosphate batteries can be used without enhanced heat dissipation.Limitations: Avoid prolonged operation near full rated load; continuous full load accelerates motor and battery degradation.
2. Medium Load (2.0 t ~ 3.5 t, Market Mainstream Lithium-ion Forklifts)Application: Raw material warehouses in manufacturing, general logistics parks, standard wooden pallet loading & unloading.Key Selection Notes: This segment features intense market competition. For long-duration full-load operation, reinforced drive axles and high-capacity batteries are mandatory; standard configurations are acceptable for intermittent operation.
3. Heavy Load (4.0 t ~ 8 t Lithium-ion Counterbalance Forklifts)Application: Steel products, moulds, heavy components, container handling.Critical Impacts:

• Higher curb weight requires reinforced frames, heavy-duty traction motors and high-voltage lithium battery systems;
• Peak current surges during full-load start-up and climbing, requiring BMS capable of high-rate discharge;
• Heavy-duty solid rubber tyres are adopted to prevent tyre deformation and collapse.Comparison Tip: Lithium-ion forklifts of the same tonnage have slightly higher curb weight than traditional lead-acid forklifts; ground bearing capacity must be verified simultaneously.

4. Large Tonnage (10 t and above Lithium-ion Forklifts)Mostly customised models. Load requirements directly define the complete high-voltage three-electric system, leading to substantial cost increases.

2. Load Centre Distance & Lift Height: Constraints for Load Derating

Key Selection Rule: Higher mast height leads to lower effective load capacity; a longer load centre reduces allowable load.Example: A 3-tonne lithium-ion forklift delivers rated 3 t capacity with a 500 mm standard load centre and 3 m mast.If equipped with a 6 m high mast, the allowable actual load may ｄｒｏｐ to 2.2–2.5 t.If extended fork sleeves or reach attachments are fitted, the load centre shifts outward, further reducing effective load capacity.

Selection Action:When handling wide goods, using extended forks or performing high-lift operations, ｓｅｌｅｃｔ the next higher tonnage model. Never specify equipment exactly matching the upper load limit.

3. Continuous Load Profile → Determines Battery Capacity & Discharge Rate Configuration

• Intermittent Light Load (short daily trips, frequent start-stop, average load ＜50% rated tonnage):Standard-capacity LiFePO₄ batteries with conventional 1C discharge capability are sufficient to control procurement costs.
• Continuous Full Load, prolonged climbing, non-stop loading/unloading (load ≥70% rated tonnage):① Adopt high-power lithium batteries with discharge capability of 1.5C or above;② Increase battery capacity to avoid temperature rise triggered by sustained high-current discharge and subsequent BMS power limitation;③ Optional battery thermal management system to prevent power derating under high temperature and the issue of "insufficient power under full load".

4. Load Characteristics Affect Drive & Hydraulic System Configuration

1. Frequent full-load climbing: Higher traction motor power and upgraded hydraulic pumps are required; otherwise insufficient climbing power and slow lifting speed will occur under full load.
2. Impact Load (rapid lifting and landing of heavy goods): Reinforced frame and mast welding plus optimised shock absorption are required. The electronic control system of lithium forklifts shall be matched with anti-shock power control strategy.

5. Load & Site Matching Selection (Ground Surface, Aisle Width, Wheelbase)

• Light load (1–2 t): 3-wheel lithium forklifts are applicable on epoxy flooring with small turning radius.
• Long-duration full load above 3.5 t: Increased wheel pressure easily damages epoxy floors. Thickened flooring or 4-wheel models with wider track are recommended to distribute wheel load.Meanwhile, heavy-duty models adopt longer wheelbase and require wider operating aisles; higher tonnage models cannot be blindly selected when aisle space is limited.

6. Special Environment: Load Superposition with Explosion-proof / Low-temperature Requirements

• Full load at low temperature: The usable capacity of lithium batteries naturally declines. Reserve ≥20% extra battery capacity during selection.
• Explosion-proof lithium-ion forklifts: The explosion-proof three-electric system faces greater heat dissipation pressure under rated full load. Long-term load should not exceed 80% of rated capacity.

III. Selection Red Lines (Risk Avoidance Key Points)

• Do not specify forklifts sized strictly for the ultimate rated load. Maintain a safety margin of 15%~25%.Example: If goods regularly weigh 2.8 t, avoid selecting a 3 t forklift; prioritise a 3.5 t lithium-ion forklift.
• Do not evaluate only unladen performance. Prioritise verification of the manufacturer’s load capacity chart. For high mast and attachment applications, determine allowable weight based on effective capacity from load charts instead of nominal tonnage on brochures.
• Long-term use of over-sized forklifts for light loads: Higher procurement cost and energy consumption increase overall TCO.
• Heavy-duty operation with standard low-capacity lithium batteries: Frequent power derating, premature battery ageing and shortened cell service life.

IV. Concise Summary (Directly Usable for Proposal Abstract)

1. Determine the minimum required rated tonnage according to cargo weight, load centre and maximum lift height by referencing load capacity charts, with adequate safety margin reserved;
2. Define battery capacity, discharge rate and thermal management demand based on intermittent or continuous full-load operating modes;
3. Upgrade motors, drive axles, wheel assemblies and mast structures for heavy-duty applications;
4. Verify ground bearing capacity and aisle width against wheel pressure under full load;
5. Further expand margins for battery and power systems if low temperature, explosion-proof and other environmental conditions apply.