Resistors for EV Charging Stations
DC fast chargers from 50 kW to 350 kW (and emerging 1 MW HPC stations) rely on resistors at multiple critical nodes. Pre-charge resistors (typically 50–500 Ω, 200–1000 W) limit inrush into DC-link capacitors before main contactor closure, preventing arc damage. Bleeder/discharge resistors safely drain the DC bus to <60 V within 5 s after disconnection per IEC 61851-23. Insulation-monitoring resistors enable IMD circuits to detect ground faults on the ungrounded DC bus, while balancing resistors equalize series capacitor banks. Surge-protection resistors paired with MOVs absorb lightning transients per IEC 61643. We supply IATF 16949–qualified aluminum-housed and high-voltage resistors validated for the 1000 VDC / 1500 VDC platforms used by CCS2, CHAdeMO and GB/T charging.
Key Requirements
- Pre-charge: 50–500 Ω, 200–1000 W with 10× pulse capability for capacitor inrush
- Discharge: drain DC bus to <60 V in 5 s per IEC 61851-23
- Working voltage 1000 VDC (CCS) up to 1500 VDC (next-gen HPC)
- Insulation resistance ≥ 100 MΩ to chassis after temperature cycling
- IATF 16949 / AEC-Q200 process traceability for vehicle-side OBC use
- Operating temperature -40°C to +125°C with humidity 95% RH non-condensing
How to Select
- Calculate pre-charge time τ = R × C; target 5τ < contactor close time (typically 200–500 ms)
- Size discharge resistor for 1.5× the IEC 61851-23 minimum to leave thermal margin
- Verify peak energy E = ½ × C × V² fits within the resistor's single-pulse rating
- Choose non-inductive winding for IMD circuits to avoid measurement distortion
- Specify conformal coating or potted housing for ≥ IP54 outdoor cabinet protection
- Confirm UL 1077 / IEC 60384-14 dielectric withstand voltage of ≥ 2.5 kV AC
Recommended Products
Aluminum Housed Resistors
Aluminum-housed resistors with superior heat dissipation — ideal for inverters, servo drives and other high-power applications
View product family
High-Voltage Resistors
Professional resistors for high-voltage pulse, discharge, X-ray and HV measurement
View product family
Wirewound Resistors
High-precision, low-noise wirewound resistors for measurement and current sampling
View product family
High-Power Resistors
Industrial-grade braking and discharge solutions covering 50W ~ 100kW
View product familyRelated Articles
How to Choose a High-Power Braking Resistor — A 2026 Engineer's Guide
Five common sizing mistakes, the formulas you actually need (with worked example), and how to read derating curves correctly.
Read article
Resistor Failure Modes and Reliability — An Engineer's Guide
Five failure modes, the physics behind each, how to detect them in test, and design rules that yield 100k-hour MTBF in real industrial environments.
Read articleFrequently asked questions
What pre-charge resistor value do I need for a 350 kW DC fast charger?
Do you offer resistors qualified for the 1500 VDC platforms used by next-generation HPC chargers?
How do I size the bleeder resistor to meet the IEC 61851-23 5-second discharge requirement?
Can the same resistor be used for both pre-charge and discharge?
Sample Request
Standard samples are provided free of charge in reasonable quantities (shipped within 2–3 business days). Custom samples are delivered within 2–4 weeks. Please use the form on the right to tell us:
- Company and contact details
- Target part number or key specs (power / resistance / package)
- Application scenario and estimated annual volume
- Shipping address and expected delivery date