The Care and Keeping of Batteries
By Rebekah Waters, FAA Safety Briefing Magazine
Batteries are an important part of any aircraft. They provide the initial power needed to start the engine, energize critical systems, and keep everything functioning. The primary role of the battery is to provide a reserve of electrical power in case the alternator fails, allowing pilots to navigate, communicate, and get the aircraft back on the ground safely. If the battery is weak or neglected, the whole system struggles — starting the engine becomes unreliable, avionics may fail, and safety is compromised. Regular maintenance keeps both the battery and the engine in top shape, ensuring smooth operation when it matters most.
Battery types vary. Most small private aircraft use lead-acid batteries, while most commercial and military aircraft use NiCad batteries. However, other types are becoming available, such as gel cell and sealed lead-acid batteries. The battery best suited for a particular application will depend on the relative importance of several characteristics, such as weight, cost, volume, service or shelf life, discharge rate, maintenance, and charging rate. Any change of battery type must comply with the aircraft’s type certification basis and may be considered a major alteration to the aircraft. To ensure safety and reliability, it’s essential to update the aircraft’s instructions for continued airworthiness (ICA) to include maintenance and inspection requirements specific to the new battery type.
Regular inspection and maintenance of aircraft batteries is crucial to ensure optimal performance and safety. Mechanics should conduct routine checks for physical damage, electrolyte levels, and signs of corrosion. Regularly inspect and clean battery terminals and keep them free from corrosion to ensure proper electrical contact. Poor connections can lead to several potentially dangerous issues, including increased electrical resistance, battery drainage, system malfunctions, overheating, and potential fire hazards. Always follow manufacturer-recommended charging procedures. Overcharging or deep discharging batteries can significantly reduce their lifespan. A good charger has the option to select the type of battery you are charging, which helps protect the battery.
Regularly inspect and clean battery terminals and keep them free from corrosion to ensure proper electrical contact.
Proper storage of aircraft batteries is crucial to maintain their functionality and extend service life. Store batteries in a dry, temperature-controlled environment. Extreme temperatures can degrade battery performance and shorten lifespan. Maintain batteries at an appropriate state of charge during storage. For lead-acid batteries, this typically means keeping them fully charged to prevent sulfation. Perform regular checks during storage to monitor voltage health and recharge as necessary to maintain optimal charge levels.
Even with proper maintenance and storage, there comes a time when batteries must be replaced. Several factors, including capacity degradation, physical damage, manufacturer’s service life limits, and safety concerns, can lead to the decision to remove and dispose of an aircraft battery. When this happens, proper disposal is crucial to ensure safety and compliance. Follow all federal and state regulations regarding hazardous materials.
Aviation mechanics who follow good maintenance and storage practices significantly enhance the safety, reliability, and lifespan of aircraft batteries, which in turn contributes to overall flight safety! To find out more about battery care, see the resources listed below.
Learn More
- Aviation Maintenance Technician Handbook — Airframe, Chapter 9
- AC 43.13–1B, Acceptable Methods, Techniques, and Practices — Aircraft Inspection and Repair
Rebekah Waters is an FAA Safety Briefing associate editor. She is a technical writer-editor in the FAA’s Flight Standards Service.
