Intelligent batteries for Inspire 1 and DJI Phantom 3 – How do Intelligent Batteries Work?
The Inspire 1 and Phantom 3 intelligent batteries are essentially the same…
The Inspire 1’s intelligent battery has many functions: Battery Level Display, Battery Life Display, Auto-discharging, Balance Charging, Over Charge Protection, Temperature Detection, Over Current Protection, Short Circuit Protection, Battery Cell Damage Protection, Battery Information History, SleepMode, and Communication.
Some functions can directly display the current state of the battery by checking whether an LED is on or off, while other functions of the battery can only be worked with DJI GO app. The app displays how much remaining power the battery has,and the system can automatically analyze and calculate the power and time required to return home and land safely, so that users will not always worry about a low battery during flight. The Intelligent Battery also displays the voltage of each battery cell, the total charging and discharging times, the health status of the battery, and so on.
There are some advanced functions, like the Inspire 1’s Smart Low Battery RTH:
When the Battery Level Indicator displays a low battery warning, the motor is not able to output enough power. Users are advised to land the drone immediately, otherwise the drone will land automatically. An automatic landing may damage the drone, endanger by standers, or cause other problems. To prevent such hazards, when low battery is triggered, the main controller of Inspire 1 can intelligently estimate whether the current power level is enough to return home from its current position. The DJI Go app will advise users to return home if this is the case. The drone will automatically return to the Home Point if no action is taken within 10 seconds. Users can cancel RTH by pressing the RTH button once. Smart RTH will only work once per flight.
Compared with a traditional battery, intelligent batteries bring pilots great convenience. Let’s see how the battery, a basic energy storage medium, developed into a multi-functional intelligent battery by looking at some of its special functions more closely.
Over Discharge Prevention
When using a battery, users often worry about over discharging. To avoid the problem, battery designers installed an over discharging protective circuit. Discharging will stop when battery reaches a preset voltage. However, if discharging stops, lots of data cannot be processed, and the drone will lose power. Hence, automatically stopping discharging is the last level of battery protection; the battery circuit also calculates the endurance of battery life and warn users to take safety measures when necessary.
For example, the Inspire 1’s battery data is integrated with its flight control data, which can provide three level battery warning protection.
1. Low Battery Level Warning – When the battery level indicator displays that the remaining battery level is 30% (the exact percentage can be set by users), the red light starts slowly flashing. Users are notified of the remaining battery level and should returnto the Home Point as soon as possible.
2. Critical Low Battery Level Warning – The drone will automatically return to the Home Point if the remaining battery level can only support the drone’s return home. The thresholds for the warning are automatically determined based on the current flight altitude and distance calculated with intelligent battery data and the flight control data.
3. Intense Critical Low Battery Level Warning – The drone will automatically land if the remaining battery level cannot support a normal RTH (return time being delayed by headwinds, for example) to avoid crashing.
The endurance of battery life is determined based on the current flight distance, altitude, and current output power of the motors. Since these elements are dynamic, all data should be calculated in real time. All this requires exceptional battery cell management and algorithm design.
Battery Charge Protection and Storage
There are some special requirements for charging lithium batteries. Currently, lithium batteries use serial-parallel battery cells. But since battery cells are different, this leads to imbalanced charging and discharging. Therefore, it is necessary touse a charging management circuit. Another function of the Intelligent Lithium Battery is that it has an intelligent charging and discharging management system.
The Inspire 1’s intelligent battery can manage the charging and discharging process, and it is also able to automatically discharge. The battery will auto discharge to around 65% if the battery level is more than 65% and it is idle for more than 10 days (users can set the exact time themselves).
Checking Battery Level in Real Time
Users used to check battery levels, output voltage, and electricity by using a multimeter, or mounting a “beep-beep” tool into the battery, which was inconvenient. Today, batteries are more intelligent and display the remaining battery and other information in real-time.
Take Inspire 1’s battery as an example:
1. You can check the remaining battery level easily. 4 LED lights display the current remaining battery level in real-time on the ground and in flight.
2. The DJI GO app will display the cell voltage of the battery by transferring voltage data from the aircraft in real time.
3. A record is stored about the battery’s history, detailing the number of uses, previous warning messages and battery life over time.
4. The Inspire’s LED light displays battery errors. It will display errors caused by short circuiting,over current charging, over voltage charging, high temperatures, low temperatures, and so on.
Here are two examples of intelligent battery functions: battery level display and charging protection display.
Battery Level Display:
No Contact Plugs
Imagine you are mounting a battery onto a DIY drone, the plug sparks. If the situation happens again, the plug will oxidize under the high temperatures when the battery discharges. The conductivity of the plug will decrease, and the plug will overheat and dissolve. Some crashes are caused by the aging electrode plugs. To solve the problem, the Intelligent Lithium Battery’s management circuit was developed.
When placing the battery into Inspire 1, the electrode contact will not discharge, so there will not be any electric erosion. As such, the life of the battery plug contact point increases. The battery will output power only after pressing the on/off button. When powering off, users should press the power button twice, and hold it the second time.
The intelligent battery’s authenticity is well protected. First, users can only use lithium batteries produced in the original factory, so the quality of the battery is guaranteed. Therefore,users must only use batteries produced by the company, or else the aircraft will not takeoff. Even if the system can be cracked, the company can upgrade the firmware accordingly.
The 5 points above explained more about the battery, battery pre-check before flight, battery storage and the benefits of protection so users can use their batteries more safety. The next section will discuss battery guidelines and notices.
Battery Usage Instructions
1. Please remove the battery from the drone while it is not being used, and keep it in a temperate environment to prevent the battery from over heating or freezing.
2. Do not charge the battery right after the flight; wait until it cools down. The charging environment should be between 0℃ to 40℃. Take care of the battery to avoid accidents.
3. Be aware of the battery during transport. A vehicle accelerating or decelerating and may cause the battery may collide with sharp objects and combust or cause other damage. Please keep batteries in a safe place while transporting in a car to prevent fire.
4. Check the status of battery before using. Lack of usage over may deplete battery power or lead to deviations in voltage level between the battery cells because of incomplete charging and discharging operations. Normally, these problems will ariseif the battery is within a 0.2V voltage deviation.
5. Please recycle a damaged battery, since lithium batteries are greatly harmful to the environment.
6. Suitable storage power range is from 50% to 65% if the battery is unused for a long time.
7. Air transportation is a concern of some users. Some are glad because of that the standard battery level of the Inspire 1 batteryTB47 is 99.9Wh, and can be carried onto a flight, since the limit of battery level is 100Wh. But the standard battery level of the optional battery TB48 is 129.96. Normally, only two of these batteries can be carried onto a flight.
8. While using the battery under low temperature environment, between -10℃ to 4℃, the internal resistance of the battery increases which leads to heavy drop in voltage. Therefore, please fully charge the battery before using. The voltage of battery cells reaches 4.35V. While the temperature is lower than 5℃, the battery needs to be fully charged, the voltage of battery cells should be higher than 4.2V, and warm-up and heat preservation actions should be taken before launching. The warm-up can be achieved with the battery heater or by hovering the drone at a low altitude for around one minute.
Many users are unfamiliar with complete discharging. For instance, the battery of Inspire 1 needs to have one complete cycle of charging and discharging after ten in complete cycles in order to calibrate the battery level.
There are two modes of discharging: the slow one and the rapid one.
Slow discharging: Install the battery into the drone, turn the battery on and leave it electrostatically discharging until it automatically turns off when the battery level lower than 5%. It is recommended not to turn on the electric motor especially those without rotating propellers, as it may lead to abrasion of the motor.
Rapid discharging: Install the battery into the drone, fly it until low battery level alerts and the drone automatically lands. Do not turn it off and keep it discharging until it automatically shuts down.
Nowadays one of the biggest limitations of the drones is the endurance of the battery. The intelligent battery can be improved to maximize efficiency or use another energy source such as hydrogen or solar energy, to extend the operationtime of the flight. If new energies can be utilized, it will be a huge step forward for the battery since its efficiency will greatly improve.
Let’s look forward to the next revolutions in intelligent battery design!
Thanks to RedHotPoker on PhantomPilots.com for information supplied.