Overview
ISO 22565:2019 - Road vehicles - Durability test method of starter relay for stop and start system - defines standardized durability tests for starter relays used in 12 V passenger-vehicle stop‑and‑start systems. The standard prescribes using a simulated electrical load to represent the starter solenoid, enabling repeatable relay endurance testing while avoiding damage to real solenoids and reducing or eliminating the need for external cooling and long cycle times.
Key Topics
- Scope and purpose
- Applies to starter relays that open/close the circuit to the starter solenoid in 12 V stop‑and‑start passenger vehicles.
- Focuses on relay durability under frequent start cycles typical of stop‑and‑start systems.
- Simulated load approach
- Uses electrical inductance and resistance values determined from the actual starter solenoid.
- If the real solenoid contains a diode, the simulated load must include an equivalent diode (forward average rectified current and reverse voltage match the real part).
- Recommends resistance materials with a small temperature coefficient to stabilize resistance under repeated operation and shorten OFF time.
- Test conditions
- Test voltage: (13 ± 0.5) V DC; power supply must reproduce actual starter relay current.
- Ambient temperature: room temperature (23 ± 5) °C.
- ON/OFF timing: ON time set to reach steady current; OFF time set to prevent unacceptable temperature-driven current drift in the simulated load.
- Target current: specific relay current targets and tolerances are to be agreed between relevant parties.
- Single‑coil vs. double‑coil solenoids
- Separate test circuits and operation patterns are provided for single‑coil and double‑coil (pull‑in and hold‑in) solenoids (see Figures 2 and 3 in the standard).
- Double‑coil tests include timed sequences for supplying both coils and for hold‑in only, with defined current conditions for each switching mode.
- Post‑test requirements
- Number of operation cycles and acceptance criteria for relay characteristics after testing are to be determined by agreement between stakeholders.
Applications
ISO 22565:2019 is intended for:
- Automotive OEMs developing stop‑and‑start vehicle systems
- Relay manufacturers and suppliers validating product durability
- Component test laboratories implementing standardized relay endurance tests
- Quality and compliance teams seeking consistent, repeatable test methods for 12 V starter relays
Practical benefits include improved test reproducibility, reduced test duration, and avoidance of starter solenoid damage through simulated loads.
Related Standards
- ISO 20574:2019 - Road vehicles - Durability test method for starter motor for stop and start system
Keywords: ISO 22565:2019, starter relay durability, stop‑start system, simulated load, starter solenoid, durability test, 12 V passenger vehicles.
