Nowadays, more and more drones are coming into our sight. Every time they see a drone in the air, many enthusiasts are eager to know how long it will take to fly on a charge.
Parameter analysis of drone battery
So I ordered a drone online for aerial photography, with a spare battery. Not surprisingly, the 1100mA drone battery is almost a quarter of the price of a drone! I’d love to see what’s so special about this battery.
We opened the product manual and saw this message. The drone has a four-point description of its flight performance, with a maximum range of 100 meters, a maximum altitude of 10 meters, a maximum speed of 8 meters per second and a maximum flight time of 13 minutes. The spare battery is 1100mah with a standard voltage of 3.8v.
From the instructions, this 1100mah battery can actually fly the drone for 13 minutes! Of course, the easiest way to test is to fill the battery and let the drone fly until it doesn’t fly on the ground. But this method is too rough and not quite right.
Test scheme of drone battery
So we designed a more reasonable test plan.
As a first step, the N6705C DC power analyzer uses the N6705C DC power analyzer to capture the current waveform of the drone over a period of time or one working cycle.
The second step is to reproduce the captured current waveform using the load function of the N6705C or N7900 high-performance power system, which simulates the true power consumption state of the drone.
The third step is to attach the intelligent flight battery to detect the end voltage and power of the battery in real time. When the voltage is below 3.5V, you can basically decide that you can no longer fly.
Testing of drone battery
So, we’ve prepared the equipment for the experiment, the N6705C, equipped with the N6756A module. 14585A Analysis Software, N7951A High Performance Power System, N7909A Power Dissipator.
First, we removed the battery of the drone and powered it with the N6705C analog battery. Let the drone make a flight. The following waveforms are captured.
Then, we started the data logger DataLogger with 14585A to operate the drone from take-off to landing, and the software recorded all changes in operating current in real time.
Thired, we captured this current waveform, flying for more than a minute. For a measure, look at the table below. From take-off to completion of landing, a total of 43 seconds. Plus the preparation time, has consumed 125mah! If so, can I install the flight for 13 minutes on the instructions?
Experimental data analysis
Now, we’re going to use the same current waveform to absorb the drone battery. Since the maximum current has exceeded 8A, we enabled the load function of the N7951A high performance power supply system. We have the following picture. Please see the following figure for wiring:
14585A software was used to edit the power consumption waveform just captured to eliminate the preparation time. Then, the waveform is fed into the load waveform library of N7951A to repeatedly simulate the take-off and landing process of the drone and continuously absorb the battery energy. We got the following picture:
The red waveform is the absorption current, which directly simulates the repeated take-off and landing process of the drone. Since N7951A is the power supply, the absorption current is negative after load function is enabled. So at the bottom of the red waveform, the absorption current is maximized, which is 10.8A during flight. And the maximum absorption current appears at the start, at 14A.
The blue waveform is the terminal voltage of the battery. It actually fluctuates wildly with the current. This is the internal resistance of the battery. When the absorption current is higher, the battery terminal voltage is the lowest. This is exactly how it works.
Analysis of experimental results
On this test chart, we measured with a ruler and got this result.
- Battery terminal voltage decreases continuously from charging saturation state. At approximately 3V, a steep drop occurred. If the plane is still flying at this time and no alarm or timely measures are taken, the result may be a drone crash.
- Take off and landing less than 10 times, time 8 minutes 34 seconds! It seems that the specification of the product is nearly 45% off.
- During the whole process, the total battery power consumed was 925mHA, 17% lower than the target.
Flight time guide for drone batteries
Here we also did flight time test data for most of the drone batteries on the market. We provide a guide for drone enthusiasts.
- Within 200mah, the ultimate battery life can reach about 5 minutes.
- Within 200~700mah, the ultimate endurance time can reach about 5~8 minutes.
- 700~1500mah ultimate battery life can be up to 8~10 minutes.
- The limit endurance of 1500~3000mah can reach about 10~15 minutes.
- The limit endurance of 3000~4000mah can reach about 15~20 minutes.
- The ultimate endurance of 4000~7000mah can reach 20~25 minutes.
- The maximum endurance of 7000~10000mah can reach about 25~32 minutes.
- The ultimate endurance of 10000~20000mah can reach 32~48 minutes.
- More than 20000mah can last 48 minutes to an hour.
The above values are subject to error. All values are for reference and are based on the actual flight time. Ultimate endurance is the duration of the flight at the last 10% alarm low voltage.
Learn more about battery
If you are interested, you can read this article. Hot! Is the drone battery 10000mah worth buying?
Keep an eye on Grepow’s official blog, and we’ll regularly update industry-related articles to keep you up-to-date on the battery industry.
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