Minimum battery temperature for APU start is which value?

Minimum battery temperature for APU start is which value?

• A. -25°C
• B. -10°C
• C. -15°C
• D. -20°C

Answer: (D)

Battery temperature directly affects the APU starter’s ability to deliver the required cranking current. Cold batteries have higher internal resistance and reduced capacity, so the start may fail if the temperature is too low. The specified minimum temperature for an APU start is -20°C to ensure reliable engagement of the starter and spin-up of the APU. If the battery is colder than this, you should warm or preheat the battery (or use external power) before attempting the start. The other values are either warmer than the minimum (allowed but not the threshold) or colder than the minimum (not permitted for a start).

Battery temperature directly affects the APU starter’s ability to deliver the required cranking current. Cold batteries have higher internal resistance and reduced capacity, so the start may fail if the temperature is too low. The specified minimum temperature for an APU start is -20°C to ensure reliable engagement of the starter and spin-up of the APU. If the battery is colder than this, you should warm or preheat the battery (or use external power) before attempting the start. The other values are either warmer than the minimum (allowed but not the threshold) or colder than the minimum (not permitted for a start).