What do we need to do if the battery voltage after starting the APU is below 24.0V?

What do we need to do if the battery voltage after starting the APU is below 24.0V?

• A. The batteries must be recharged for 30 minutes by the APU generator
• B. The batteries should be replaced immediately
• C. The APU should be restarted and rechecked after 5 minutes
• D. The electrical load should be reduced to minimum

Answer: (A)

When the APU is running, its generator charges the 24-volt battery system. If the battery voltage remains below 24.0 V after starting the APU, the proper action is to let the APU continue to recharge the batteries for about 30 minutes. This gives the charging system time to bring the battery back toward its normal level and confirms there isn’t an immediate fault. Replacing the battery right away isn’t warranted because a discharged battery can often recover with sustained charging. Restarting the APU isn’t needed since the goal is to complete the charging, and reducing the electrical load isn’t the prescribed corrective action in this scenario. If the voltage is still below 24 V after the 30-minute recharge, then a fault in the battery or charging system should be investigated.

When the APU is running, its generator charges the 24-volt battery system. If the battery voltage remains below 24.0 V after starting the APU, the proper action is to let the APU continue to recharge the batteries for about 30 minutes. This gives the charging system time to bring the battery back toward its normal level and confirms there isn’t an immediate fault. Replacing the battery right away isn’t warranted because a discharged battery can often recover with sustained charging. Restarting the APU isn’t needed since the goal is to complete the charging, and reducing the electrical load isn’t the prescribed corrective action in this scenario. If the voltage is still below 24 V after the 30-minute recharge, then a fault in the battery or charging system should be investigated.