It is very important to have relevant information and understanding about LiPo batteries if you want to achieve ideal flight time and top quality performance.
Similar to most of the drone parts, batteries are related to other components of drones. The ideal drone batteries are greatly dependent on the size of your drone and the type and number of motors employed in the machine. Lithium Polymer batteries play a significant role when it comes to ensuring that you enjoy an extended mid-air flight adventure. Poor standard batteries can certainly disrupt your flying experience and cause your frustration. In this instructional guide, we will share with you tips and techniques on how to make your LiPo batteries work efficiently with your drone well before you even purchase them.
Table of Contents
Knowing What Size Battery You Need
By using larger batteries in terms of capacities, you can achieve longer flight durations. Batteries with greater capacities are always an enticing choice for the dronies. However, you need to be careful that your drone batteries remain within the optimum takeoff weight for your drone. You can learn more about ways and approaches to determine the optimum takeoff weight for your drone by going through the post titled how to choose motors, propellers and ESC for your drone. Physical size and dimensions of the drone batteries are other important factors. Since, with a certain category or type of drone, you will only be able to fit drone batteries of certain specific types in them.
Battery Discharge Rate and Capacity
The most crucial yet ignored factor is to check the optimum value for the battery discharge C rating of your drone. Using a discharge rate (C rating) that is well below the required magnitude, can damage your battery physically and also reduce the efficiency of your drone’s performance. This reason is that the battery in such a case cannot release enough current to power the motors. However, drone batteries with higher C ratings are heavier. If you are using batteries with C rating that is higher than the optimum value, then you will just be carrying additional weight that is no longer required and should be jettisoned at your earliest. This can reduce your flight duration considerably. Obviously, as avid drone fans, reduced flight times would always be serious turn offs. Hence, you would definitely want your drone to be as light in weight as possible.
How to Calculate the Maximum Continuous Current of Your Battery
We can calculate the total current drawn from your entire drone system using the simple formula mentioned below:
Maximum Continuous Current Drawn from Battery (Amperes) = Battery Capacity (Ah) x Discharging Rate (C)
For example, we have a 5100 mAh 3 cell LiPo battery with a 10C rating. To determine the maximum continuous current of your battery, we first convert 5100 mAh into 5.1 Ah and multiply it with 10 C rating to get 5.1 A current.
How to Find Optimum C Rating
Choosing the appropriate battery is generally the last step involved in creating your own drone. At this stage, we are aware of the motors and ESC that we have employed in our UAV. Motors are basically responsible for drawing the majority of energy from batteries. Hence, we can formulate our calculations around these assumptions.
You can get an idea about maximum continuous current drawn by looking at the specifications of your motors. The thrust data tables can be of great use for you in this regard. For example, our quadcopter with four motors weighs around 2 Kg in total along with the battery and other components. In this scenario, the quadcopter will hover over a certain location when each motor produces about 500 g of thrust. Now, since we are utilizing the MT2213 motors with 10 inch propellers, we can take a glimpse of the thrust data table to determine the maximum current drawn at optimum thrust, which, in this case, is just under 10 A.
With four motors being used in our quadcopter, the total current drawn will be 4 x 10 A = 40 A. Other components and features such as autopilot and First Person View will also draw out current in milliamperes so we can neglect their effect. But to stay on the safe side, let’s add a total of 1 A current to the original value of 40 A and round off the total current drawn to 41 A. Now, the 5100 mAh 10 C battery, which was being discussed earlier, is likely to work fine since the maximum current that can be drawn from it is 51 A. However, we can also do fine by using a C rating of lower value say 8C so that we get a lighter battery. Having said that, it is not a common practice to observe batteries with C ratings lesser than 10C.
We can achieve optimum flight time by employing a battery with a current output of just around 25 A. However, during our mid- air flight adventures, we are likely to fly at higher throttle values when the drone is getting to a higher altitude or in case of inclement weather conditions. Hence, at various stages during a flight, the maximum current drawn could be even higher than this value which can damage the our battery fatally.
The Battery C Rating Depends on Capacity
There is no constant C rating of a battery. The maximum current output of a battery depends on its capacity and C rating. As a rule of thumb, the smaller the capacity of a battery, the higher will be its C rating. That is precisely the reason, most of the high capacity multirotor batteries have values of C rating in the low region around 10 to 15 C.
How Much Capacity Do I Need?
Having figured out the required current drawn out from your battery, you can determine the capacity and C rating accordingly. Ideally, you will be better off by purchasing a battery with the highest capacity possible. As discussed above, you also need to be careful that the total weight of the quadcopter including the battery and other components remains at about 50 to 70% of the optimum rotor thrust.
Now, just getting back to our previous example, we know that 50% rotor thrust is approximately 500 g per motor. Hence, the total thrust for all the four motors of our quadcopter will be 2 Kg. The weight of our drone’s frame, electronics and other components sums up to be 1.2 Kg. This implies that we are left with 800g to 1000g to play with in terms of battery. Hence, according to this example, you should be looking for a LiPo battery that boasts the highest capacity and weighs less than this critical value.
Battery Voltage (Cell Count)
The cell count or battery voltage is another important factor that you need to take into account while choosing the best drone batteries. Your motors are able to generate more power via batteries with larger voltage rating. Having said that, batteries with higher voltage turn out to be heavier in weight as they contain more cells.
When talking about battery voltage, there is no rule of thumb that can be suggested. You can always determine the best voltage for your drone by taking a glimpse at the thrust data tables and comparing the efficiency. You will reach the conclusion that motors generally turn out to be more efficient and powerful when they are made to use batteries with higher cell count and hence higher voltage. However, with a battery of higher voltage, an inevitable increase in weight and cost of the battery are also to be kept in mind. Therefore, based on the number of motors used in your quadcopter or multi-rotor, you will have to decide what best works for you.
Another aspect that needs to be taken care of is that the motors/ESC and other electronic elements are able to provide ample support to the battery voltage. There are some motors that are only compatible with certain kinds of cell count LiPo. There are others which only support certain specific range of voltages. So, you need to keep all these things in mind while choosing the best drone batteries for your drone.
Battery Connectors
It is always a tough task to try and solder battery connectors. We, therefore, suggest you to find out a connector that best suits your needs and predilections and stick to it. This enables the pilots to replace batteries with the minimum of fuss possible. Moreover, if ever you decide to build a new drone in the future, you can always resort to using these batteries. Some of the common types of connectors include Deans/TPlug, XT60, EC3 connectors and others. You can take a look at our connector guide if you are interested in getting detailed information about battery connectors.
Number of Batteries
The number of batteries that you decide to use with your UAV do not matter a lot. There are advantages as well as disadvantages associated with using more drone batteries. Firstly, additional batteries produce an extra safety layer. In case, one of your battery runs out of juice, you can always revert to one of the additional batteries and use it to land safely. In addition, if one of the batteries gets a bit older than the other ones, you always have the luxury of getting it replaced with a new one. With a couple of battery chargers in your arsenal, you can always use them simultaneously to charge two batteries. Having said that, it is always a complex affair to install and wire two batteries. Also, purchasing two batteries instead of one can always prove to be more expensive. Therefore, it all comes down to your personal choice and preference whether you want to stick to a single battery or want to go for a couple of batteries.
What is the Best Battery Brand?
All of you would certainly agree with us that drone batteries comprise one of the most important drone parts. Let’s share with you some of the leading brands in terms of battery quality and performance. It would definitely be a stupid bargain if you decided to save a few bucks just to see your drone come down crashing due to a battery failure. As far as batteries are concerned, the more you invest in them, the richer dividends you are going to reap. The batteries that are same on paper in terms of specifications but low on cost may get discharged too quickly or start to drop in performance after a few charge/discharge cycles. However, the drone batteries manufactured by trustworthy brands can certainly last longer. Large reduction in voltage can also be observed in lower cost batteries which can result in reduced flight durations. Having said that, even if a cheaper drone battery does not last longer, you can always replace it with another cheaper one more often than not. Nevertheless, here is our list of the leading drone battery brands based on our experience and expertise.
GensAce and TATTU Batteries
When it comes to batteries with best quality and excellent performance, GensAce are far ahead of their competitors in producing LiPo batteries of the highest calibre. If you are looking to purchase some really professional batteries, then we suggest you to go for GensAce TATTU LiPo batteries series. All these batteries have been able to clear the UN 38.3 battery test with flying colors. This is the highest quality standard test for Lithium Polymer batteries and is not test by most of the batteries manufacturers. They are placed at the higher end of the price scale but investing in them is worth every penny. If you are carrying an expensive drone in your armory, it would be sheer idiocy not to invest in top quality drone batteries.
Turnigy/Multistar
Turnigy (hobbyking) are very popular among dronies as they churn up low cost batteries which render superb performance. We have been using these drone batteries. They certainly are a good investment when it comes to hobby drone builds. However, in comparison to GensAce batteries, they do not stand a chance as they are not able to provide the requisite charge/discharge cycles.
If you have any battery manufacturers in mind who are producing remarkable drone batteries, you can let us know in the comments section below.
