What are the backup battery specifications?

What are the backup battery specifications?

• A. 12 VDC, 7 Ah Gel
• B. 24 VDC, 5 Ah NiMH
• C. 24 VDC, 3 Ah Lead-acid
• D. 24 VDC, 5 Ah Lead-acid

Answer: (D)

Backup power is meant to feed the aircraft’s essential DC bus for a defined emergency duration, so the voltage must match the bus and the capacity must be enough to sustain critical loads. This airplane’s essential system is designed for 24 V DC, and the backup battery needs to provide that voltage with enough energy storage to cover the required standby time. A 24 VDC, 5 Ah lead-acid battery fits these needs well: it matches the bus voltage, delivers reliable energy, and offers the necessary discharge characteristics for an emergency duration. Lead-acid is a robust, well-understood choice for standby power in aviation due to charging compatibility and cost. The other options don’t fit because they either use an incorrect voltage for the essential bus or have insufficient capacity or nonstandard chemistry for this backup role.

Backup power is meant to feed the aircraft’s essential DC bus for a defined emergency duration, so the voltage must match the bus and the capacity must be enough to sustain critical loads. This airplane’s essential system is designed for 24 V DC, and the backup battery needs to provide that voltage with enough energy storage to cover the required standby time. A 24 VDC, 5 Ah lead-acid battery fits these needs well: it matches the bus voltage, delivers reliable energy, and offers the necessary discharge characteristics for an emergency duration. Lead-acid is a robust, well-understood choice for standby power in aviation due to charging compatibility and cost. The other options don’t fit because they either use an incorrect voltage for the essential bus or have insufficient capacity or nonstandard chemistry for this backup role.