ISO 23625:2025 PDF

Overview

ISO 23625:2025 - Small craft - Lithium-ion batteries - specifies requirements and recommendations for selecting, installing and documenting lithium‑ion batteries on small craft. It applies to lithium‑ion batteries and battery systems with a capacity greater than 500 Wh used for general electrical loads and/or electric propulsion. The standard is primarily intended for manufacturers and battery installers and replaces ISO/TS 23625:2021 with expanded guidance on BMS, EMC and protection devices.

Key technical topics and requirements

• Scope and applicability: Batteries > 500 Wh; warning that DC systems operating at potentials ≥ 60 V have additional requirements not covered by this document.
• System design: Installations must follow ISO 13297 and the battery manufacturer’s recommendations; systems must keep batteries within the manufacturer’s safe operating limits (SOL).
• Battery Management System (BMS): A BMS is required to protect against overcharge, overdischarge, high/low temperature events (HVC/LVC/HTC/LTC) and to provide battery cut‑off under hazardous conditions. EMC requirements for BMS are included.
• Standards compliance: Batteries shall meet IEC 62619 and IEC 62620 requirements.
• Alarms and operator notification: For propulsion or critical systems, the BMS must notify the operator with a visual and/or audible alarm (75–85 dB(A) at 1 m) before disconnecting the battery.
• Installation practices: Protection from shock, vibration, corrosion and heat; adhere to specified temperature limits and storage guidance; no series connection of different chemistries; provide overcurrent protection and appropriately rated contactors/disconnect devices.
• Ingress protection: Components in flood‑prone locations must meet IP67; others should meet IP55 (IEC 60529).
• Higher‑level requirements: For propulsion installations > 1 500 Wh, the system shall be capable of indicating state of health relative to original capacity.
• Safety information: Manufacturers must supply required safety information and an operator’s manual.

Informative annexes cover battery thermal runaway, protection devices, and protection device examples.

Practical applications and users

• Who uses ISO 23625:2025:
  • Marine battery manufacturers and OEMs
  • Small craft designers and boatbuilders
  • Marine electrical installers and service technicians
  • System integrators of electric propulsion and hybrid drives
  • Surveyors and certification bodies assessing battery installations
• Practical uses:
  • Specification and selection of marine lithium‑ion battery systems
  • Installation checklists and commissioning procedures
  • BMS configuration, alarm strategy and safety documentation
  • Risk mitigation for thermal runaway, corrosion and water ingress

Related standards

• ISO 13297 (small craft electrical systems)
• ISO 8846 (ignition protection)
• ISO 25197 (control systems)
• IEC 60529 (IP code)
• IEC 62619 and IEC 62620 (secondary lithium battery safety and performance)

Keywords: ISO 23625:2025, small craft, lithium‑ion batteries, marine batteries, battery management system, BMS, safe operating limits, battery installation, battery safety, electric propulsion.