Forklift batteries are specified by voltage, amp-hour (Ah) capacity, and physical dimensions. These three parameters must match your forklift's requirements exactly—voltage mismatches can damage controllers, incorrect dimensions may not fit the battery compartment, and insufficient Ah capacity will not last a full shift.
Voltage – The Non-Negotiable Match
The battery voltage must exactly match the forklift’s motor and controller specifications.
Voltage Typical Application Forklift Class
24V Light-duty, smaller electric forklifts (1,500–3,000 lbs) Class I, III
36V Medium-duty (3,000–5,000 lb capacity models) Class I
48V Medium-duty (4,000–6,000 lbs), widely used in Class I and II Class I, II
72V / 80V Heavy-duty models (8,000+ lbs), large counterbalance forklifts Class I
96V High-capacity, heavy-duty applications (8–15 ton) Class I
⚠️ Critical: Installing a 48V battery in a 36V forklift can overheat motors and cause over $2,000 in repairs.
Amp-Hour (Ah) Capacity – Runtime and Shift Length
Ah capacity determines how long the battery can power the forklift before needing a recharge.
Shift Type Recommended Ah Capacity Typical Runtime
Single shift 300–600 Ah 6–8 hours
Double shift 600–1,000 Ah 8–12+ hours
Heavy continuous use 700–1,200+ Ah 10+ hours
Common Capacity Examples:
Toyota THDE2000-24 (20,000 lb capacity): 1,125 Ah, 36V
Clark S-Series (lead-acid): up to 625 Ah
Clark TM25: 625–735 Ah, 36V
Flux Power M36: 630 Ah (24.2 kWh) or 840 Ah (32.3 kWh)
Redway Power 80V lithium: 690 Ah
Pro Tip: A 48V 750Ah lithium pack can replace a 1,000Ah lead-acid unit, saving approximately 40% weight.
Physical Dimensions – Compartment Fit
Battery dimensions vary by class and manufacturer. Even a 1-inch overhang risks damaging cables or voiding warranties.
Voltage Typical Dimensions (L×W×H) Notes
24V ~400×200×300 mm Compact units; walkie stackers, pallet jacks
36V ~30″×20″×30″ (762×508×762 mm) Common in medium-duty forklifts
48V ~40″×25″×32″ (1,016×635×813 mm) Most popular configuration
48V 775Ah ~42″×20″×38″ (1,067×508×965 mm) High-capacity 48V unit
80V ~980×760×580 mm Large heavy-duty lithium pack
Example – 36V 1020Ah Battery (18-85-25):
Dimensions: 18 cm (H) × 85 cm (L) × 25 cm (W)
Dimensions (imperial): 38.125″ L × 29.125″ W × 22.625″ H
Energy: 36.72 kWh
Runtime: 10+ hours in 4-ton forklifts
Weight – Counterweight and Stability
The battery acts as part of the forklift's counterweight. Too light compromises stability; too heavy strains the drive system.
Voltage / Type Typical Weight
24V lithium (200–500 Ah) 300–700 lbs (135–320 kg)
36V lithium (400–800 Ah) 700–1,200 lbs (320–540 kg)
48V lithium (400–1,000 Ah) 900–1,800 lbs (410–820 kg)
48V 775Ah lead-acid ~3,200 lbs (1,450 kg)
80V 690Ah lithium ~2,645 lbs (1,200 kg)
Note: Lithium-ion batteries are typically 30–40% lighter than equivalent lead-acid batteries.
Lead-Acid vs. Lithium-Ion Specifications
Feature Lead-Acid Lithium-Ion (LiFePO4)
Voltage 24V, 36V, 48V 24V, 36V, 48V, 80V
Cycle Life 1,000–1,500 cycles 2,000–5,000+ cycles
Charge Time 8–10 hours + 6–8 hour cool-down 1–3 hours (as fast as 1 hour with dual fast chargers)
Energy Efficiency 70–80% 95%+
Maintenance Weekly watering, equalization None – sealed, maintenance-free
Weight Heavier 30–40% lighter
Energy Density 50–80 Wh/kg 150–200 Wh/kg
Temperature Range Limited -22°F to 122°F (with thermal management)
IP Rating N/A Up to IP69-rated
Brand-Specific Battery Specifications
Toyota:
Series / Model Voltage Capacity Key Features
5/35 Series (Lithium) 24V, 36V, 48V Various 3,500 cycle warranty, maintenance-free
8/50 Series (Lithium) 24V, 36V, 48V Various 5,000 cycle warranty, IP69-rated
THDE2000-24 36V 1,125 Ah Heavy-duty 20,000 lb model
Clark:
Model Voltage Capacity Dimensions (L×W×H) Weight
TM25 36V 625–735 Ah 32.5″×17.5″×29.5″ 2,200–2,500 lbs
S-Series 48V Up to 625 Ah (lead-acid) Varies Varies
S-Series Lithium 48V 460 Ah (or 280 Ah optional) Varies Varies
General Specifications (Examples):
Model Voltage Capacity Dimensions (L×W×H) Weight
Leoch FP24-100 (Lithium) 25.6V 100 Ah 340×330×280 mm 24 kg
Leoch FP48-105 (Lithium) 51.2V 105 Ah 585×328×234 mm 50 kg
Leoch FP72-44 (Lithium) 73.6V 44 Ah 529×278×228 mm 25 kg
Ironclad (Lead-Acid) 12V 276–2,064 Ah Varies Varies
Summary
Forklift batteries are specified by voltage (24V, 36V, 48V, 72V, 80V, 96V), Ah capacity (100–1,200+ Ah), and physical dimensions. Always match voltage exactly to the forklift's specifications—mismatches can damage controllers and motors. Lead-acid batteries offer lower upfront cost but require weekly maintenance, while lithium-ion batteries cost more initially but deliver 2–5× longer cycle life, zero maintenance, and 30–40% weight savings. For precise sizing, consult your forklift's data plate or contact the manufacturer with your model number.