IEC 62973-3:2024

Overview - IEC 62973-3:2024 (Lead acid batteries for rolling stock)

IEC 62973-3:2024 is the industry standard that defines the framework for selecting, qualifying and operating VRLA lead acid batteries used as auxiliary power supplies on railway rolling stock. It complements IEC 62973‑1 and adapts relevant clauses from existing battery and safety standards to the specific environmental, mechanical and electrical conditions encountered on trains. Charging systems themselves are excluded; the document focuses on battery cells/monoblocs, containers and related subcomponents.

Key topics and technical requirements

The standard provides prescriptive guidance and test references for safe, reliable battery use in rail applications, including:

• Battery types and definitions - VRLA (valve-regulated lead acid) cells, monoblocs, trays, crates and battery boxes.
• Environmental and mechanical requirements - operating temperature ranges, shock & vibration criteria, ventilation and installation orientations.
• System requirements - system voltage considerations, battery sizing inputs/outputs, and charge retention (self‑discharge) expectations.
• Charging and discharging performance - float/boost charge characteristics, temperature compensation, discharge profiles and compliance with energy demand/load profiles.
• Safety & protection - deep-discharge behavior, thermal considerations, fire protection and recommended safety measures.
• Subcomponent requirements - containers, charging controls, temperature probes, nameplates and marking/labeling rules.
• Electrical interface & markings - external connections, nameplate content and safety signs for battery boxes, trays and cells.
• Storage, transport and maintenance - handling instructions, storage conditions and routine maintenance guidance.
• Testing and qualification - type tests and routine tests including dielectric tests, load profile verification, shock & vibration, and electrical checks. Annexes provide test sequences, dielectric test parameters and a method to verify compliance with energy demand.

Practical applications and target users

IEC 62973-3:2024 is intended for professionals involved in design, procurement, installation, testing and operation of battery systems on railway vehicles:

• Rolling stock manufacturers and systems integrators specifying auxiliary power systems
• Battery manufacturers and test houses qualifying VRLA lead acid cells for rail use
• Railway operators and maintenance organizations defining lifecycle and safety procedures
• Certification bodies assessing compliance with railway electrical safety and performance requirements

Related standards and implementation notes

• Complements IEC 62973‑1 (general framework for railway battery systems).
• Selects and adapts clauses from established battery and safety standards (normative references listed in the document).
• Charging systems are explicitly excluded; refer to applicable charging-system standards when specifying chargers.

Keywords: IEC 62973-3:2024, railway batteries, VRLA lead acid batteries, rolling stock auxiliary power, battery qualification tests, battery sizing, railway battery safety.