November 04, 2017
When starting in the drone races world, it’s common to feel clueless about the best components to create your own drone, one that beats all the other competitors in velocity, lightweight, stability, and efficiency. Obviously, among all the necessary elements to make a functional drone, one of the most important is the battery, providing power to all components and keeping it running as long as the match goes on.
Like other electronic devices that need batteries to work, the world of RC devices has gone through a quite interesting development process, not just because they have increased its power storage capacity, but also because they have become so much smaller and powerful when compared to its predecessors.
Evolution of LiPo batteries for your drone.
Even before the drones age, the world of radio controlled vehicles competitions already existed, but the level of complexity of these cars, vessels, and even aerial vehicles was much more dependent on mechanical components, nowadays drones depend more on technology research and development. This allows improving drones performance levels, by adding sensors, transmitters o telemetry components. This increased the energy demand of this little but sophisticated flying objects, pushing companies to design ever lighter, longer lasting and more efficient batteries, so drones can fly faster and for a longer period of time. In the beginning, the only available batteries for drones were NiMh and NiCd, which fulfilled their purpose but were heavy and sometimes worked below the engines maximum capacity. Nowadays we can count on Lithium Polymer batteries, better known as LiPo, these batteries are lighter and provide as much power as the user needs allowing to have more powerful and quicker vehicles.
LiPo batteries are rechargeable but unlike cellphones batteries (NiCd or NiMh), LiPo batteries do not suffer from memory effect, meaning that their charge performance is not affected by constant discharge cycles, neither their service lifetime or their power storage capacity get diminished by it. Additionally, these batteries have been designed connecting their cells in parallel to increase their power by summing each cell capacity, according to the different components requirements available in the market.
Characteristics that you should bear in mind when buying LiPo batteries for your drone.
When purchasing a LiPo battery, you should bear in mind 3 essential characteristics that are related to the power, duration and delivery capacity they can provide without putting in risk any electronic component or the battery itself. Let’s review each one of this features separately.
- Potency or cells number: A LiPo battery is built by a series of cells connected each other, this connection is based in a parallel circuit and each cell has a capacity of 3.7 volts (V). The number referencing how many cells are stacked up together is usually referenced as an “S” in any battery model.
An S1 battery has only a 3.7 V cell, whereas an S3 has 3 cell of 3.7 V each, and therefore it's real voltage is 11.1 V, in other words, 3.7 V x 3 cells. This feature is important because most of the electronic components related to drones indicate with a number followed by an "S" letter the required voltage to reach optimal performance.
- Duration of the battery or mAh: This feature indicates the energy storage capacity that a battery has, so the bigger this number is, the longer your drone will fly. But generally, the batteries with great storage capacity are bigger, heavier and much more expensive than the rest.
It is advisable to drone competitors to look for one that doesn't hold back your drone by adding weight and to be able to hold the flight time of a match without turning the low battery warning.
- Discharge capacity or C rate: This references the capacity of a battery to deliver the energy the drone requires without sustaining any damage or stressing other components of the drone. The nomenclature that identifies this characteristic is a number followed by a letter “C”.
A 25C means that we need to multiply 25 by the battery capacity in Amps to get the maximum sustained load you can safely put on the battery. For instance, a 25C 2000mAh battery will deliver up to 50 Amps as the maximum sustained load you can safely put on the battery. Going higher than that will result in, at best, the degradation of the battery at a faster than normal pace. At worst, it could burst into flames.