This Flying Replacement Battery Will Extend Flight Time For Drones

The US Air Force has planes that can perform long-range missions using tanker aircraft for in-flight refueling. This has inspired UC Berkeley researchers to come up with a unique way to help small drones stay in mid-air nearly indefinitely: flying replacement batteries which can be switched without having to land.

Using four propellers not only means better stability for quadcopter drones as they hover in position but it also means they can be moved quickly. There have been more drone races, but they barely last more than a few minutes as four propellers need the same number of electric motors, draining their battery fast. If we add more batteries to drones, they become heavier, hence the requirement for stronger motors, meaning drone flights will eventually reach their limit length and drones will need new batteries.

Swapping a new power pack for drone racers is not a problem. For other applications such as parcel delivery and long-range reconnaissance, however, it’s not the best thing to land for a battery change, which can lead to time delays as well as unwanted complications. So, the researchers looked for a different way, coming up with replacement batteries that can fly and connect to larger drones as they fly.

This process involves unplugging and plugging a cable, so the research team made a quadcopter that has a landing pad with electrical pads mounted on top. The replacement battery, coming with its own motors and propellers, is designed for flying up as well as meeting the larger drone. Then, as soon as the craft stabilizes itself, the battery will touch down on its landing pad. Next, it transfers power via its landing legs that have electrical contacts.

The researchers created a prototype, powering it with a 2.2 Ah lithium-polymer battery able to keep it in the sky for around 12 minutes. Each replacement battery features 1.5 Ah of capacity, extending the flight time of the prototype by about 5 minutes. Once the battery lands, it powers all the motors and electronics on the main drone instead of recharging the primary battery. Hence, while the landing pad o the drone isn’t in use, it drains the primary slowly. However, testing proved that the concept helps boost the total flight time of the prototype from 12 to more than 60 minutes.

Apparently, the researchers still have to overcome several logistical problems to make their approach viable. Moreover, there must be replacement batteries set up along the flight path of a drone to extend its range, which isn’t hard to do in big cities. But it can be complicated for autonomous military drones which typically fly in areas where it’s problematic to set up bases for flying replacement batteries.