FAA Part 107 Remote Pilot (UAG)Loading and PerformanceEasy
A remote pilot preflights a multirotor sUAS on a morning when the battery temperature reads near freezing. The manufacturer's manual warns against launching with cold batteries. What is the primary concern?
- ACold temperatures slow the battery's internal chemical reactions, reducing available capacity and usable flight time
- BCold temperatures have no measurable effect on lithium battery performance
- CCold temperatures increase battery capacity by lowering internal resistance
- DCold temperatures speed up the battery's chemical reactions, causing overcharging
Show answer & explanationAnswer & explanation
Correct answer: A. Cold temperatures slow the battery's internal chemical reactions, reducing available capacity and usable flight time
Low temperatures slow the electrochemical reactions inside lithium batteries, increasing internal resistance and reducing the amount of usable capacity, which shortens flight time and can cause voltage sag under load. Pilots should warm batteries to the manufacturer's recommended range before flight.
Why the other options are wrong
- B. Lithium batteries are notably temperature-sensitive, so this is incorrect.
- C. Internal resistance actually increases in cold conditions, not decreases.
- D. Cold slows reactions rather than speeding them; overcharging is unrelated to temperature in this way.
Cold Weather Battery Performance
Low temperatures slow the internal chemical reactions of lithium batteries, reducing capacity, increasing internal resistance, and shortening flight endurance.
- Batteries should be warmed to manufacturer-recommended temps before flight
- Cold batteries can show sudden voltage sag under load
- Reduced capacity translates directly to shorter flight times
Memory trick: A cold battery is a sluggish battery — it just doesn't want to work.