Aircraft battery storage is a critical, yet often overlooked, aspect of aviation maintenance. It plays a vital role in the safety and reliability of aircraft operations. Proper storage and maintenance significantly impact battery performance, longevity, and overall aircraft safety.
We often focus on visible aircraft components like engines or wings. However, the battery is crucial, powering essential systems, especially during emergencies. Understanding aircraft battery storage is vital for everyone in aviation, from mechanics to pilots.
The Importance of Proper Aircraft Battery Storage
Proper aircraft battery storage extends lifespan and ensures readiness. Improper storage reduces capacity, increases self-discharge rates, and can cause permanent damage. Temperature is key in battery storage; certain temperature ranges like between 70°F and 90°F are the ideal battery temperature, while other temperatures can impact battery life. Lower temperatures can affect the battery’s internal resistance, and temperature extremes can even affect the freezing point of the battery.
Temperature Effects on Battery Performance
Temperature significantly impacts battery storage. The discharge rate is significantly impacted by the ambient temperature around the battery. The table below illustrates this:
| Storage Temperature | Time to Reach 50% Charge |
|---|---|
| 20°C (68°F) | 15 months |
| 30°C (86°F) | 9 months |
| 10°C (50°F) | Over 18 months |
Cooler temperatures extend the time for a battery’s open-circuit voltage to self-discharge to 50% capacity. Many aviation maintenance facilities have dedicated cold storage for aircraft batteries.
Types of Aircraft Batteries and Their Storage Requirements
Different aircraft battery types have unique storage requirements. Lead-acid and nickel-cadmium (Ni-Cad) are the most common in aviation. The number of battery cells, whether it is a cell battery, dry charged or flooded can make a difference.
Lead-Acid Batteries
Lead-acid batteries are common in smaller aircraft. These batteries require attention during storage to prevent sulfation, which reduces capacity and service life. Lead antimony terminals on the positive and negative terminal can suffer from corrosion and sulfation also occurs in lead-acid battery cell.
To store lead-acid aircraft batteries:
- Fully charge the battery before storage.
- Store in a cool, dry place, ideally between 0°C and 20°C (32°F to 68°F).
- Check the voltage every 3-4 months.
- Recharge if voltage drops below 12.4V for a 12V battery or 24.8V for a 24V battery.
Nickel-Cadmium (Ni-Cad) Batteries
Ni-Cad batteries are prevalent in commercial aircraft for their higher energy density and longer shelf life. They also have certain requirements to keep their charging voltage and discharge rate as intended by the battery manufacturer. Improper handling can lead to extreme cold and even electrolyte freezing within the battery cell.
For Ni-Cad battery storage:
- Store between -20°C and 30°C (-4°F to 86°F).
- Maintain a 10% to 30% charge. For flooded batteries ensure they have the appropriate electrolyte level, where as sealed lead-acid and other types are checked through voltage.
- Deep cycle every 6 months.
- Store in a dry environment.
Emerging Technologies in Aircraft Battery Storage
Aircraft battery technologies are always evolving. Lithium-ion batteries are a promising development.
However, implementing lithium-ion batteries has presented challenges. In 2013, Boeing’s 787 Dreamliner was grounded due to battery fires (source). This highlighted the need for battery management and storage systems, particularly with newer technologies. Ensuring that the charging method for newer batteries is sufficient, for example having a battery charger plugged into ground power may or may not be sufficient and more specific equipment may be necessary.
Despite setbacks, research continues into safer and more efficient batteries. NASA is developing a sulfur-selenium battery with double the energy density of lithium-ion batteries (source). Ensuring cells connected within the series aircraft circuit are all balanced to prevent short circuit and maintain adequate emergency power.
Best Practices for Aircraft Battery Storage
Universal best practices exist for aircraft battery storage. Keeping the batteries at the appropriate temperature will help prevent issues such as electrolyte freezing or a decrease in charge rate and even thermal runaway. Having an effective voltage regulator is also helpful in maintaining proper voltage within a circuit. It’s also critical to follow procedures such as documenting any discharged battery to avoid improper use.
- Regular Inspections: Check for damage, corrosion, or leakage.
- Proper Documentation: Keep records of conditions and maintenance.
- Environmental Control: Maintain stable temperature and humidity.
- Safety Precautions: Follow safety guidelines.
- Rotation: Use a first-in-first-out system.
The Future of Aircraft Battery Storage
Aircraft battery storage will become increasingly important. The trend toward more electric aircraft demands advancements in battery technology and storage methods. Even in general aviation, voltage drops caused by an excessive electrical load can result in unintended circumstances.
A lithium-sulfur-powered electric version of the Colt with a 200 nautical mile range is under development. This demonstrates the potential of new battery technologies. Understanding how much electric current a charged battery has to sufficiently provide for all electrical equipment including radio communications and landing gear deployment is critical to understanding the limits of aircraft electrical.
These advancements also present storage challenges. As batteries become more powerful, proper storage is vital. If charged batteries are exposed to extreme cold or heat this can significantly decrease the lifespan of a battery. In cold conditions there are additional considerations, such as extreme cold that could lower a discharged battery voltage past a critical point that could lead to electrolyte freezing. If this is suspected, ensuring a ground power is used as part of a proper charging method may be sufficient for batteries.
FAQs about aircraft battery storage
Where do you store batteries on a plane?
Aircraft batteries are typically in a dedicated compartment near the nose. This compartment protects the battery and contains potential leaks or fires.
What is the most commonly used storage battery for general aviation aircraft?
Lead-acid batteries are most common in general aviation due to cost, reliability, and history. Some newer aircraft utilize nickel-cadmium or lithium-ion batteries.
What are the rules for aircraft batteries?
Aviation authorities like the FAA set rules for aircraft batteries including inspections, maintenance, and replacement. Batteries must be certified and meet safety standards. There are also regulations for transporting spare batteries. In general aviation the pilot will refer to what the battery manufacturer recommendations are in addition to regulatory guidelines to determine when battery service and replacement are required. For cell batteries where multiple cells connected produce a battery’s voltage output, a bad or aging battery cell can result in overall degradation in performance even if the other cells in the battery are good, therefore replacement of a full battery will typically be needed once cell battery begins having problems with any one of it’s individual cells, even if other cells within the battery still technically meet standards individually. This is where battery charger analysis devices come into play where instead of measuring total circuit voltage and determining whether it falls within an acceptable range or measuring open circuit voltage of a cell battery or a multi-cell battery such as an acid battery or lead acid battery with several cells where acid battery cell voltage might fall within acceptable tolerances, but if connected into a cell battery the overall cell battery itself may be less capable and less ready to take on heavy current, such as when an airplane engine needs to turn on it’s starter to spin up the engine, where the discharge current, otherwise known as starting current of the starter will put tremendous draw on the cell battery.
Why are lithium batteries forbidden in aircraft?
Lithium batteries aren’t entirely forbidden but are strictly regulated due to fire risk. Some aircraft utilize lithium-ion batteries with stringent safety measures. Passenger limitations exist on size and quantity carried onboard or in checked luggage. These safety considerations apply to individual lithium batteries as well as cell battery configurations with lithium.
Conclusion
Aircraft battery storage is a complex and vital part of aviation maintenance. Proper storage extends the battery’s lifespan and ensures readiness. Factors like temperature, battery type, and emerging technologies influence ideal storage methods. When fully charged the battery is storing energy to provide electrical power later, a chemical reaction allows electricity to be discharged from batteries for providing an electric current through the battery cell to whatever requires the electrical energy. Conversely when an electric current is applied to a battery such as a fully charged or partially discharged battery that needs additional power and electric current added back into it. Proper charging rates and discharging rates as prescribed by the manufacturer, which are available to reference in your series aircraft pilot operating handbook are extremely important to make sure your battery stays charged up as much as possible. As part of pre-flight duties of an airplane, after ensuring there is sufficient circuit voltage measured for the entire series aircraft and not just a single acid battery or lead acid battery that provides electricity, next a voltage regulator is checked that shows there is appropriate battery charging happening, ensuring not too much electricity is applied or too little current is applied from the charging source, which if this fails the aircraft requires immediate maintenance because if a battery cannot properly charge during flight operation and only discharges, or alternatively if the battery gets an excessive amount of electrical energy this will significantly reduce it’s battery life as it may not fully recharge later as some of the capacity of the acid battery may be lost in some of the acid battery cells which could occur in lead acid batteries or even in some types of lithium batteries, even in airplane batteries designed for aircraft use as opposed to normal batteries used in things not part of an airplane. Once sufficient battery charging is checked on the ground the plane then is capable to fly, once the engine starts through starting it from a discharged battery, otherwise the emergency power is usually what powers airplane engine starting, however the discharged battery and even when the discharged battery becomes fully charged later when in use while the airplane is running there could also be issues in addition to having proper open circuit voltage in certain batteries and charged batteries and charging voltage is what determines how much electric current the battery requires during it’s operation, this all plays into understanding how charged batteries have various chemical reactions based on the type of cell and number of cells in the battery that are connected, even open circuit voltage can be tested once the battery is disconnected to understand what chemical reactions occur after discharge of batteries to determine if the batteries typically can provide the intended level of service they should after recharging the discharged batteries with electric current at the recommended charging rates according to your battery manufacturer which may also be mentioned in your airplane owner’s manual for the series aircraft to understand any specific instructions in regard to acid battery or acid batteries specifically. Pilots usually prefer acid battery or lead acid batteries that can typically withstand electrolyte freezing, where extreme cold weather in particular for smaller private series aircraft could have this occur. It is very important to prevent this for batteries as in most small series aircraft an acid battery may provide the power for emergency operations should engine power be lost, therefore not just ground power but also internal to the series aircraft how a discharged battery after starting up the engine then goes to becoming a fully charged battery during normal flight operations when enough current is applied to the battery or battery cells at the right charging rate, and whether that is flooded, sealed, lead acid battery cells, cell batteries and other series aircraft factors come into play and will require consulting with both regulatory guidance such as from FAA and the recommendations from your battery manufacturer to maintain airplane battery health in the series aircraft, no matter the specific model you fly. Lead acid batteries are usually very sensitive to extreme temperature, so maintaining good battery temperature and knowing the typical operating temperature range are helpful to properly maintain airplane battery charging circuits where voltage drops caused by too much discharge and not enough charging rate, whether ground power or from the airplane itself are all factors that come into play for battery care.
As aviation evolves, so will battery storage. From battery chemistry to storage systems, the future presents new challenges and opportunities. Staying informed about best practices in aircraft battery storage is crucial for safe and reliable flights. Proper storage techniques contribute to overall aviation safety.
