Overview
ISO/TS 23625:2021 - Small craft - Lithium‑ion batteries provides requirements and recommendations for selecting and installing lithium‑ion battery systems on boats. It applies to battery systems with a capacity greater than 600 Wh used for general electrical loads and/or electric propulsion on small craft. The technical specification is primarily intended for manufacturers, battery installers, marine electricians and system integrators responsible for safe battery installation and operation.
Key topics and technical requirements
This specification addresses practical safety, design and installation topics for marine lithium‑ion batteries, including:
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System design requirements
- Keep batteries within the manufacturer’s safe operating limits (SOL).
- Install a Battery Management System (BMS) (internal or external) to control and protect all batteries.
- Size systems according to application, C‑rating and manufacturer limits.
- Avoid connecting different chemistries in series/parallel; do not use combining relays across chemistries.
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Safe operating limits (SOL)
- Adhere to manufacturer‑defined voltage, current and temperature limits.
- Account for capacity fade, storage conditions and state of charge (SOC) effects.
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General installation
- Locate batteries to avoid extreme ambient temperatures and hot spots.
- Protect BMS electronics and connections from corrosion; use IP67 enclosures where exposed to water.
- Meet ignition protection requirements (ISO 8846) where applicable.
- Provide overcurrent protection per ISO 13297; ensure fusing AIC is not exceeded (subdivide banks if needed).
- Secure battery banks to limit movement (pull tests specified).
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Fire protection and cell venting
- Provide compartment ventilation to open air or independent ventilated containers; consider fire detection (ISO 9094) for enclosed spaces.
- Understand thermal runaway risks (see Annex A).
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BMS functionality and testing
- BMS must be fail‑safe, tested by a recognized laboratory, and manage overcharge, overdischarge, over‑temperature and balancing.
- Implement High Voltage Cutout (HVC) and Low Voltage Cutout (LVC) actions, alarm the operator (visual/audible at the helm) and isolate sources if needed.
Applications and who uses this standard
ISO/TS 23625:2021 is used by:
- Boat and small craft manufacturers integrating lithium‑ion power systems
- Marine battery installers and electricians
- System integrators for electric propulsion and on‑board power systems
- Design offices, yards and safety assessors creating compliant battery installations
Practical uses include specifying BMS features, designing battery compartments, selecting overcurrent protection and ventilation strategies, and creating operator manuals and safety instructions.
Related standards
Relevant documents referenced or recommended in practice:
Keywords: ISO/TS 23625:2021, lithium‑ion batteries, small craft, BMS, marine battery installation, safe operating limits, thermal runaway, battery safety.
