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

How Generators Charge Aviation Batteries?

Most airplanes need to have a set of batteries for their operations. Even if an airplane features combustion jet engines, it will still need some form of power storage to power everything from onboard instruments to lighting fixtures. Take the Boeing 747 as an example, as this jumbo plane is provided with two batteries. One of these batteries is used as the main power source in flight for electronics, while another battery performs duties as an Auxiliary Power Unit or APU.

The type of battery an airplane uses can vary depending on the needs and requirements of a particular model. Lead-acid and nickel-cadmium batteries are the most common power sources for small airplanes. Meanwhile, large aircraft typically use nickel-cadmium batteries for their external power needs.

The electronics in airplanes require power, and regardless of what type of battery you use in your aircraft, they will eventually run out of resources. In order to keep your aircraft's electronics functioning, you must recharge your batteries during flight. However, how do airplanes recharge their batteries during operations?

Generators Recharge Aviation Batteries

The generator in an airplane is responsible for recharging its batteries. They are similar to the alternators found in cars and they convert mechanical energy into electricity which then gets supplied to the plane's multiple electrical systems and lights, among other things.

During long-distance travel, airliners use jet engines that burn a combination of fuel and oxygen in the combustion chamber to power their flight by creating thrust which propels the vehicle forward. In addition, the same combustion jet engines are connected to generators. While creating energy to keep the engine in the air by burning the mixture of jet fuel and air, they also rotate the generator they are connected to. The generator converts the mechanical energy produced by combustion jet engines into electricity, which is then used to recharge airplane batteries.

The generator supplies a constant voltage using a voltage regulator that automatically maintains the voltage required to charge the battery through the aircraft electrical system. A battery switch is included in the system to disconnect the battery when the airplane is not in operation.

Generators Supply Power

Nowadays, instead of using batteries as the primary power source, most airplanes have started using generators as a power source for their electronics. Planes are now using batteries only during the flight take-off stage for the required power. Nevertheless, as soon as the aircraft reaches the sky, they switch to generators for their power requirements, such as powering cabins, lights, and air conditioning systems. The generator will also supply power to the airplane's batteries.

Battery Maintenance

It is important to inspect your batteries regularly. With a bit of care, your battery can last for years. Performance depends on how old the battery is, its health, state-of-charge levels, and mechanical integrity. Always follow the battery manufacturer's approved procedures for maintenance.

Nevertheless, you can follow these steps to enhance your battery life:

  1. Always record the installation date of the battery. It will help you determine the age of your battery during maintenance.
  2. In the case of a lead-acid battery, you can use a hydrometer to determine the specific gravity of the electrolyte, which is the weight of the electrolyte compared to the weight of pure water.
  3. It is critical to consistently follow procedures approved for the specific aircraft and battery system. This way, you can ensure that your batteries deliver particular performance levels.


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September 23, 2022
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