Practice Test Geeks(BMS) Battery Management System Certification Practice Test
← All BMS Flashcard Decks

Diagnostics Maintenance & Safety Standards Flashcards

7 cards from real BMS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Diagnostics Maintenance & Safety Standards flashcards as text

  1. A BMS activates its thermal runaway pre-alarm based on a rate-of-rise temperature threshold. What value typically triggers this alert in Li-ion systems?

    Answer: 10°C/min

    A temperature rise rate exceeding ~10°C/min is commonly used as a thermal runaway precursor alarm threshold in Li-ion battery safety standards including IEC 62619.

  2. Which NFPA standard specifically governs the installation of stationary energy storage systems including lithium-ion batteries?

    Answer: NFPA 855

    NFPA 855 is the Standard for the Installation of Stationary Energy Storage Systems, covering siting, spacing, fire protection, and operations for Li-ion and other battery technologies.

  3. A passive balancing circuit dissipates energy as heat through resistors. What is the primary maintenance concern associated with passive balancing during high-frequency cycling?

    Answer: Cumulative thermal stress leading to resistor failure or PCB delamination

    Passive balancing resistors generate continuous heat during balancing; repetitive thermal cycling causes solder joint fatigue and PCB delamination over time.

  4. Under UL 9540A test methodology, what is being evaluated when a single cell is driven into thermal runaway within an assembled module?

    Answer: The potential for cell-to-cell thermal runaway propagation within the module

    UL 9540A specifically tests thermal runaway propagation — whether one cell in runaway will trigger adjacent cells — to assess fire hazard at module, unit, and installation levels.

  5. A field technician notices that a battery pack's BMS is logging repeated over-temperature faults during charging even though ambient temperature is 22°C. The first diagnostic step should be:

    Answer: Check the pack's thermal management system (cooling fan, liquid coolant flow)

    Overtemperature during charging at normal ambient most likely indicates a cooling system failure; verifying coolant flow or fan operation should precede component replacement.

  6. According to IEC 62133-2, what is the required outcome of the forced internal short-circuit test for cylindrical Li-ion cells?

    Answer: No fire or explosion; leakage is acceptable

    IEC 62133-2 requires that cells subjected to forced internal short-circuit must not catch fire or explode; some leakage or venting is considered an acceptable pass outcome.

  7. State of Health (SOH) is most accurately determined in the field by:

    Answer: Performing a full charge-discharge cycle and comparing delivered Ah to rated capacity

    A full charge-discharge capacity test comparing actual delivered ampere-hours to the rated nameplate value is the most accurate direct measurement of SOH.