PAS 63100:2024 | Section 5 – System Controls and Integration

Section 5 addresses requirements for system controls, battery management systems, and responses to failure modes.

Section 5.1 – System Controls

The system controls for Powerwall 3 comply with BE EN IEC 62933-5-2 and includes a battery management and monitoring system (BMMS).

Section 5.2 – Failure Modes

This section requires the BMMS to undertake appropriate actions for detected failure modes, which Powerwall 3 does in compliance with all applicable product standards (including the product standards listed in the PAS). The PAS also requires that systems installed within a dwelling include visual and audible warnings in case of a battery fault or persistent dangerous condition; however, this is not required in any of these product standards.

Issue

  1. Relying on a system that is in the middle of a failure event to trigger an alert may set false performance expectations - if a system is in a persistent failure condition, it is not reasonable to expect a reliable alarm to originate from this (failing) system.
  2. For such an alarm system to provide true customer value and protection, detailed performance and test criteria should be set in the appropriate product standard. Without a robust test and validation framework, very different performance can be expected across different manufacturers.

Recommendations

Energy Storage Systems are already designed/required to take corrective protective actions (e.g. shut down) when significant faults are detected; for example, UL 1973 validates the robust mitigation and control features that are part of the Battery Management System (BMS). Tesla recommends that the potential addition of alarms be added to the work program of the international product standard development teams. This work should define what conditions could trigger an alarm, and establish a test procedure with clear pass/fail criteria. In this way, a reliable, robust, and consistent means of providing the intent of PAS section 5.2 could be provided to customers.

If a dependable fire alarm system is required, this should be provided by an external and separate fire alarm system. In this way, the device relied upon to provide the alarm is not the device that is experiencing a failure.