One of the major drawbacks relating to consumer drones is battery life. Some of the best have an advertised battery life of 25-30 minutes and increased battery size is generally not viable for small consumer UAS due to their limited lift capability.
Factors that decrease battery life, giving you an effective battery life of, at best, 10-15 minutes:
- Using the camera, and particularly streaming video to your controller.
- Batteries degrade over time and store less energy. Think about that cell phone that is almost up for an upgrade and lasts about 2 hours on a charge!
- Cold weather decreased battery efficiency. This isn’t limited to UAV batteries – even the amazing Telsa has seen decreased battery performance.
- Power reserve to return home safely. Typical 333 Exemptions have offered to land when battery power is down to about 30%. While hobbyists aren’t required to keep such a reserve, it is a good idea!
Solar power isn’t ready for prime time on land-based fixed structures, at least in my opinion, because the costs are astronomically high and the cells are made from relatively toxic materials. Below is a diagram of the costs of various forms of energy, and you’ll see that solar is the most expensive. However, given the drawbacks associated with batteries on UAS (and that your home electrical outlet can’t run a UAS), solar is promising. But to this point, it has been expensive and bulky.
This is where Alta Devices, based in the Silicon Valley, comes in. They are developing ultra-thin solar panels for a wide array of devices, and have partnered with Airware to incorporate them into UAS. The cells are only about 100 µm thick and are made of a gallium arsenide base. Here is a short video about how their cells are made and work:
They were acquired about a year ago by Hanergy, an Chinese clean energy company, after it was reportedly having trouble raising investment capital. However, the recent news appears to show that they have the capital to develop their products and are having some success. I’ll keep an eye on it and see where it goes.
Here is a video put on in conjunction with the Department of Energy:
– Duke of Drones