Drones are awesome flying machines, and as a drone enthusiast, I can’t get enough of them in the air. But all good drones come with certain limitations like telemetry range, the lag time between the controller and the drone, i-e latency, and, most importantly, the flight time. So, how long does a drone battery last?
I hate this phrase, but I will say it anyway; It depends.
Let’s dig down and see why you can’t fly your drone in the air indefinitely without the need for recharging or replacing batteries.
Factors affecting battery timing
A typical drone battery consists of a complex electro-chemical mixture of electrolytes and multiple electrodes that work via ion-exchange to power our drones. No one factor affects the battery timing alone; rather, its a combination of multiple variables that determine how long a drone can stay airborne on a single charge.
Let’s have a look at the most common factors.
Battery tech has evolved so much over the last few decades. If you have been into drones, you might have heard of the terms LiPo, NiCd, NiMH, etc. All these are types of dry cell batteries based on their electrolyte composition.
LiPo is the most commonly used cell type in drone batteries. It stands for Lithium Polymer, most famous for its high energy density (energy stored per unit weight of the battery) thanks to the lightweight nature of lithium metal. Due to its high single cell voltage (3.6v), the battery construction is quite simple. The discharge curve is comparatively flat, giving a uniform operation profile throughout the flight. They can also be manufactured in the desired shape (tubular, rectangular, etc.). Different cell configurations can be put together to get the desired discharge current, voltage, and charge storage capacity to suit the operational profile of the drone. These factors make LiPo the perfect candidate for most modern drones and other electronics.
Other battery types like Nickel Cadmium (NiCd) and Nickle Metal Hydride (NiMH) are also used occasionally in drone flights where suitable. Still, LiPo types dominate the drone industry due to their very obvious advantages.
You can learn more about the battery types and their properties at Battery University.
So to summarize this section, your drone flight time depends on the type of battery used, the cell configuration, and the charge storage capacity.
Weight of drone & Add-ons
A heavy drone requires more power to get lifted in the air than a lighter drone. So, to get higher flight time with the same battery, you will have to cut down the weight of the drone as much as possible.
The weight of a drone is increased when more add-ons are added, like cameras or prop guards. These add-ons add functionality or protection at the expense of flight time. So, its a trade-off between the two.
A sample test conducted on Parrot AR Drone 2.0 with added load vs. flight time graph shows the following behavior. Note that as we add more weight, the flight times decrease.
Remember that when it comes to flight time optimization, every gram matters.
Motor & propeller types
If you are getting off the shelf drone from companies like DJI or Yuneec, you don’t have to worry about the right motor and propellers as they are already well-optimized for the flight time. However, if you are someone who like to assemble things from scratch once in a while, do remember that the choice of motor and propeller has a significant impact on flight time for the same battery.
First of all, the pitch of the propeller has to be according to the max load you will be lifting. High loads require high pitch props, but they have more drag and hence consume more power. If you are just going to fly around without any additional gears, go for a low pitch propeller set to maximize battery timing.
Similarly, a small-sized motor will struggle with lifting high load and will have to perform inefficiently, resulting in lower flight time. On the other hand, a motor bigger than the load requirement will add additional unnecessary weight to the drone reducing the flight time.
So to maximize the flight time, you will have to optimize both the motor and the propellers, but as I mentioned above, you don’t have to worry about this if you are buying an off the shelf machine. This is for those who want to get their hands dirty once in a while with custom builds.
This might come as a surprise to some newer drone enthusiasts, but outside temperature significantly affects battery discharge and hence the flight time. If you operate the drone at a low temperature, you will notice a drastic reduction in total flight time. This is because LiPo batteries discharge incompletely under low temperatures.
The optimum temperature for LiPo battery discharge is between 0℃ to 35℃. For each battery pack, the optimal operating curve is provided by the manufacturer, which looks something like the diagram below. Notice the different discharge curves under different operating temperatures. At around 25℃, the discharge time (x-axis) is highest for this curve.
If you operate your drone at low temperatures occasionally and for a short time, the damage caused to the battery will be temporary, but if you make it a routine, you can permanently damage the battery and reduce its charging capacity considerably. Always follow the manufacturer’s recommended operating temperature for prolonged battery life.
Another environmental variable that can affect your battery timing is the wind direction. Flying against the wind is analogous to swimming against the current. It consumes more power and hence drains the battery more quickly.
Whenever the manufacture promises a specific flight time, it is under perfectly still wind conditions.
To get prolonged flight time, try to get airborne when there is little or no wind.
Some of us are daredevils and are aggressive flyers, while others fly more smoothly. It’s like our individual driving habits. When you suddenly push the throttle to make sharp turns or do aggressive maneuvers, you are drawing a large amount of current from the battery in a very short time. This power surge depletes the battery rapidly. On the other hand, if its a calm Sunday afternoon and you are in a mellow mood, flying around smoothly enjoying the scenery on your screen, you will get better air time with the same battery.
Avoiding sudden power surges is also good for the battery in the long term.
Just like any other system, your battery needs constant care while charging and discharging. Most of the things mentioned above deal with how the battery is discharged while in use. While the discharge profile affects battery life and flight time, the charging method also plays an important role.
A few things to keep in mind while safely charging your LiPo batteries to maximize your drone flight time;
- While charging your batteries, make sure the temperature range stays between 5 and 45°C. Charging while batteries are too cold or too hot will damage the capacities in the long run.
- Set the upper limit voltage of charging to not go above 4.22V. This feature is present in almost all modern chargers.
- Use your batteries within 48 hours of charging. If you are not going to use them, discharge the battery to the storage voltage of 3.8V – 3.9V.
- Do not charge the battery right after a flight. The batteries are hot, and this can damage the cells. Wait till they cool down to room temperature.
- Always use the manufacturer’s recommended charging station.
So, how long does a drone battery last?
Summing up from our above discussion, on a single charge, a typical drone battery can last somewhere from 5 minutes to as high as 31 minutes depending on the size, type, and make of the drone. These are all the commercial drones that you can buy off the shelf. However, people have built DIY drones with flight time as high as 97 minutes.
The below table summarises the flight times of most current drone models [UPDATED SEPTEMBER 2020]
|Drone Models||Advertised Flight Time (mins)||Price|
|DJI Mavic 2 Zoom||31||Check on Amazon|
|DJI Mavic Mini||30||Check on Amazon|
|DJI Mavic Pro||27||Check on Amazon|
|Blade Chroma 4K||30||Check on Amazon|
|DJI Phantom 4 Pro||30||Check on Amazon|
|Traxxas Aton Plus||25||Check on Amazon|
|Yuneec Typhoon H3||25||Check on Amazon|
|Yuneec Q500+||25||Check on Amazon|
|Parrot Bebop 2||24||Check on Amazon|
|UPair One||18||Check on Amazon|
|Hubsan H501S Pro||20||Check on Amazon|
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