Electric air heater unit STW series

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EV PTC Heaters by KLC
KLC designs PTC and high-voltage PTC heaters for electric vehicles, providing self-regulating, fast-response heating for cabins, batteries and charging-station enclosures. Products include IP68-rated variants and models compatible with 12V–800V vehicle platforms; UL/CSA certification options available.

What Is an EV PTC Heater?
An EV PTC (Positive Temperature Coefficient) heater is a self-regulating electric heater whose resistance increases with temperature, reducing current draw automatically. This behavior prevents overheating and simplifies thermal control. In EVs, PTC heaters are used for cabin heating, battery preconditioning and rapid defogging, offering predictable thermal response and improved safety compared with constant-resistance elements.

Key Applications

• Cabin heating: PTC air heaters for HVAC ducts. Typical power: 1.5–3 kW for passenger EVs; 3–6 kW for electric buses.
• Battery preheating: Indirect air heating around the battery pack to maintain cells above −10°C and protect range and longevity. Typical power: 3–8 kW for large packs.
• Defogging/defrosting: Integrated with HVAC for fast windshield and mirror clearing.
• Seat and steering wheel heating: Compact OH/TH-type modules, typically 30–200 W per zone.
• Charging-station enclosures: IP68 options to prevent freezing of electronics in outdoor DC fast chargers.

Benefits: why PTC Heaters Work in Electric Cars

• Self-regulation: Resistance rises with temperature, reducing current and preventing overheating without complex control.
• Fast response: Reach operating temperature within seconds, improving cold-start comfort and reducing preconditioning needs.
• Compact and lightweight: Examples: MH-type cross-section 26×90×L mm for easy HVAC integration.
• High-voltage safety: STW series rated for 400V–800V platforms with galvanic isolation and thermal fuses.
• Range preservation: Self-regulation lowers average power draw versus fixed-resistance heaters under real-use cycles.

Why EV Thermal Management Starts with the Right Heater
Cold weather reduces driving range and affects battery performance. Correct heater sizing and placement are critical: in KLC test conditions a 2 kW MH-type heater raised a cabin from −17°C to 12°C in 30 minutes, demonstrating the impact of targeted heater selection.

KLC PTC Heater Recommendations by Electric Vehicle Type and Voltage (table representation)
Vehicle Type | Voltage Range | KLC Recommended PTC Heater | Key Applications | Heating Capacity
Electric Bus | 350V–800V DC (commonly 600V) | STW High-Voltage Series | Cabin heating, driver seat heating, large-area windshield defogging | 3 kW – 6 kW
Electric Truck | 400V–1000V DC (commonly 600V–800V) | STW High-Voltage Series | Cabin HVAC, battery airflow warming, control box heating | 3 kW – 8 kW
Electric Car | 200V–800V DC (commonly 400V/800V) | STW & MH Series | Passenger cabin comfort, battery preheating | 1.5 kW – 3 kW

High-Voltage Platform Compatibility
Modern EV platforms use 400V or 800V architectures. KLC STW-series covers target ranges (e.g., 450–520V and 500–999V variants) with galvanic isolation and built-in thermal fuses. UL certification is available for AC systems up to ~600V; support for custom certification above standard thresholds is provided.

KLC’s Engineering Credentials

• Founded 1982; 40+ years designing and manufacturing PTC heaters.
• In-house capabilities: 3D CAD, CFD thermal simulation, prototype testing, HALT/HASS lifecycle validation.
• Quality & certifications: IATF 16949, ISO 9001; UL / CSA / VDE available.
• IP68 waterproof/dustproof options for outdoor and charging-station use.
• Field-proven deployments and validated cabin heating data in cold climates.

Key Specifications (summary)
Voltage: 12V–999V DC/AC (typical EV coverage 12V–800V; UL ~600V AC limit noted)
Power: 30 W–9,999 W
Protection: optional IP68 waterproof/dustproof
Certifications: UL / CSA / VDE; manufactured to IATF 16949 and ISO 9001 processes
Applications: cabin heating, battery preheating, HVAC auxiliary heat, seat heating, charging-station enclosure heating
Platform compatibility: 400V and 800V EV systems; legacy 12V–48V platforms supported via MH/MSH/SH/OH/MTH series

Selection Guide

• Voltage: Match heater rating to traction-battery voltage (e.g., 400V pack → 450–520V STW; 800V pack → 500–999V STW).
• Power: Cabin heating typically 1.5–3 kW for passenger EVs; battery preheating 3–8 kW depending on pack volume.
• Airflow: Verify heater rating at specified airflow (KLC standard test: 6.4 m/s) and fan compatibility.
• Environment: Use IP68 variants for underfloor/rooftop or outdoor installations.
• Certification: UL/CSA for North America; VDE for Europe; custom certification support available.

Testing & Validation

• Airflow and heat-distribution testing at multiple fan speeds.
• Lifecycle testing simulating 10+ years of vehicle use.
• Vibration, humidity and thermal-shock testing per automotive standards.
• Thermal safety validation including over-temperature and blocked-airflow scenarios.

PTC Heater Types & Typical Dimensional Notes

• MH type: nominal cross-section 26 × 90 × L mm; multiple lengths available; power examples: 2,000 W / 2,500 W.
• MSH / SH / TH / OH types: varied cross-sections and fin pitches for seats, zones and ducts.
• STW (High-Voltage) series: modular designs from very small elements to large-format assemblies; single-element power up to model-dependent maxima.

Technical specifications

• Model family highlighted: STW series (High-Voltage PTC heaters for 400V/800V platforms).
• Voltage range: 12V–999V DC/AC (typical EV coverage 12V–800V).
• Power range: 30 W – 9,999 W (modular single-element capability).
• Protection: optional IP68 variants for outdoor/charging-station use.
• Certifications: IATF 16949, ISO 9001; UL, CSA, VDE available.
• Key applications: cabin heating, battery preheating, defogging/defrosting, seat/steering heating, charging-station enclosure heating.
• Test condition note: maximum power reported at air speed 6.4 m/s (KLC standard).
• Example dimensions: MH-type nominal cross-section 26 × 90 × L mm; STW sizes range widely by model.
• Safety features: self-regulating ceramic element, built-in thermal fuse, galvanic isolation for 400V+ models.
• Lifecycle: designed for 10–15 years or ~150,000–250,000 km equivalent usage per KLC validation.