AS9120B, ISO 9001:2015, AND FAA AC 0056B ACCREDITED

What is the Purpose of an Aircraft Battery?

When you think about all the components on an aircraft that require electricity, it becomes easy to appreciate the role that batteries play in aviation. While not the primary source of electrical power during routine operations, batteries can supply energy to various entertainment, comfort, navigation, and other systems that would otherwise be dysfunctional in case of generator failure. In this blog, we will discuss one of the fundamental components of an aircraft's electrical system, the battery.

Most modern aircraft are equipped with a lead-acid or nickel-cadmium battery used primarily during the preflight startup sequence but can be utilized at any time during the flight. Particularly, batteries provide power to various electrical systems on the ground and the starter motors in the engine. After takeoff, the engine and APU drive generators that supply power to the critical electrical systems for the remainder of the flight. Some of this energy used by the generators feeds back to the primary battery to recharge it so that it can be used in case of generator failure. In such a situation, the battery should have enough charge to power any essential systems until the aircraft can safely land. In addition to the primary battery, several computers and emergency light systems have external batteries to prevent even transient loss of power.

Aircraft batteries are constructed similarly to other common rechargeable batteries, those of which include cells made of an anode, cathode, and electrolyte stored in a casing. In a cell, the negative anode terminal loses electrons to the positive cathode terminal. As the electrons flow through the cell, chemical energy is converted into electrical energy that can be used by any connected components or devices. In rechargeable batteries such as those used in aviation, the capacity is typically measured in amperes/hour. A common aircraft battery, for example, may be rated at 17Ah, meaning that it could provide 17 amperes for one hour or 1 ampere for 17 hours. Inevitably, the capacity of a rechargeable battery will drop linearly with time. FAA regulations regarding aircraft electrical systems mandate that no battery should drop below 80% of its original capacity and should thus be tested regularly.

Regular inspection and maintenance of aircraft batteries help attenuate the small but dangerous risk of failure. Most primary batteries should be inspected and tested for capacity every 3 months and generally have a lifespan of 1 1/2-2 years, at which point the capacity typically drops below 80%. When recharging on the ground or in flight, the source should be continuous and not exceed the safe voltage level.

In instances where a battery is charged to an excessive amount, or there are several cases of overvoltage in a short time, the electrolyte can boil and become dysfunctional. If overcharging is not recognized and stopped quickly, a thermal runaway may cause an explosion. Conversely, if the battery is exposed to a low temperature for too long, the electrolyte can freeze over and cause damage to the casing. Finally, leakage from lead-acid batteries can cause extensive corrosion to adjacent components.

When purchasing a new aircraft battery products or other related components, it is crucial to find a reputable source. At Stacked Aviation, we offer customers great deals and rapid lead times on an inventory of over 2 billion high-quality components for the civil and defense aviation industries. With our strict NO CHINA Sourcing policy and several quality assurance measures, customers can expect satisfaction from receiving the highest-caliber parts possible. Additionally, we offer same-day and next-day shipping options on a number of in-stock components, making us the perfect choice for customers with AOG requirements. Explore our vast parts catalog today and receive a quote at any time through our instant RFQ service.


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