25/11/2020
How to use and maintain lithium batteries for drones. (Bagaimana cara guna dan penjagaan bateri lithium untuk kegunaan drone padi anda)
Usually, the full name of the lithium battery we use on drones is "lithium polymer battery" (English Li-Polymer), or lithium battery for short. Lithium battery is a new type of battery with many advantages such as high energy density, miniaturization, ultra-thinness, light weight, high safety and low cost. The surface of the lithium battery is aluminum-plastic encapsulation, which is different from the metal shell of the liquid lithium battery. Any hidden dangers inside can be immediately revealed through changes in the outer shape, such as the bulge of the lithium battery.
The lithium battery is used in the model aircraft, and the rated voltage of the single-chip battery is 3.7V, which is obtained from the average working voltage. The actual voltage of a monolithic lithium battery is 2.75~4.2V, and the electric quantity marked on the lithium battery refers to the electric quantity obtained by discharging from 4.2V to 2.75V. Lithium batteries must be used within the voltage range of 2.75~4.2V. If the voltage is lower than 2.75V, it will cause excessive discharge, the shape of the lithium battery will expand, and the internal chemical liquid will crystallize. These crystals may pierce the internal structure layer and cause a short circuit, or even cause the lithium battery voltage to become zero. If the single-chip voltage is higher than 4.2V during charging, it will cause overcharging. The internal chemical reaction of the battery is too intense, and the lithium battery will also swell. If you continue to charge, it will catch fire or even explode. Therefore, it is especially important to select a charger that meets safety standards to charge the lithium battery correctly!
Another important reminder: remember that the voltage of the single-chip battery of the UAV power battery cannot be used to 2.75V, because the battery can no longer provide effective power for the aircraft to fly, so for safe flight, we can use the single-chip battery The alarm voltage is set to 3.6V. Once it approaches or reaches this voltage value, the pilot must immediately perform a return or landing action, so as to avoid the explosion of the aircraft due to insufficient battery voltage.
Usually, we use the multiple C (the first letter of Capacity in English) to indicate the discharge capacity of the battery. Common UAV batteries have 10C, 15C, 20C or higher C-number batteries. For example, if a battery with a capacity of 20000mAh lasts for 1 hour, the average current is 20000mAh, which is 20A, and 20A is the 1C of this battery. If the battery is labeled 20000mAh/20C, then the maximum discharge current of this battery should be 20A×20C=400A, if it is 10C, then its maximum discharge current is 20A×10C=300A. Therefore, the higher the C number of the battery, the greater the discharge current the battery can provide. Therefore, the higher the C number, the higher the price. It should be noted that: do not exceed the discharge C number of the battery to discharge, otherwise, it may cause the battery to be scrapped or fire and explode.
Correct use of batteries is the best way to extend battery life
Adhere to six "nos" when using batteries:
1.Not enough
There are requirements for chargers. Some low-quality chargers have imperfect power-off functions after being fully charged, resulting in a monolithic battery that is fully charged to 4.2V and has not stopped charging. In addition, after some chargers have been used for a period of time, due to aging of components, There will also be problems full of non-stop. Therefore, we recommend that someone be present when charging the lithium polymer battery. When the charging time is too long, manually check whether the charger is malfunctioning. If there is a malfunction, unplug the battery as soon as possible, otherwise the lithium polymer battery will be overcharged. The battery life is affected in the slightest, and in the worst case, there is a direct explosion and fire.
Also remind everyone: When charging, you must charge the battery according to the specified charging C number or a lower C number, and cannot exceed the specified charging current.
2.Can not discharge for a long time
The discharge curve of the battery shows that the voltage drops relatively quickly when the battery is first discharged. When the discharge reaches between 3.9V and 3.7V, the voltage drop slows down. But once it drops to 3.7V, the voltage drop speed will increase again, and poor control will lead to overdischarge. In the light of the battery damage, the voltage is too low to cause the bomber. Some model friends will over-discharge every time they fly because they have fewer batteries, which will seriously reduce the battery life. A good strategy is to fly one minute as little as possible, and one more cycle of life. It is better to buy two more batteries than to fly the batteries to the limit of battery capacity each time. To make full use of the battery alarm, you should land as soon as possible.
3.Can't save at full power
A fully charged battery cannot be stored for more than 3 days at full charge. If it is not discharged for more than a week, some batteries will swell up, and some batteries may not swell temporarily, but after several full charge storages, the battery may be directly scrapped. . Therefore, the correct way is to charge it after receiving the flight mission. If there is no flight mission within 3 days after the battery is used, please charge the single chip voltage to 3.80~3.90V and save it. If the battery does not fly due to various reasons after being charged, the battery should be discharged to 3.80~3.90V within 3 days after being fully charged. If the battery is not used within three months, continue to store the battery after charging and discharging it once to extend the battery life. The battery should be stored in a cool environment. When storing the battery for a long time, it is best to put it in a sealed bag or a sealed explosion box. The recommended ambient temperature is 10~25°C, and it should be dry and non-corrosive.
4.Can not damage the skin
The outer skin of the battery is an important structure to prevent the battery from exploding and leaking and catching fire. The damage of the aluminum-plastic outer skin of the lithium polymer battery will directly cause the battery to catch fire or explode. Handle the battery gently. When fixing the battery on the airplane, the cable tie should be tightened. Because it may crash during a large dynamic flight, the battery will be thrown out due to the loose tie, which will easily cause damage to the battery skin.
5.No short circuit
This situation often occurs during battery welding wire maintenance and transportation. A short circuit will directly cause the battery to ignite or catch fire and explode. When you find that the battery is disconnected after a period of use and you need to re-weld the wires, pay special attention to the electric soldering iron not to touch the positive and negative electrodes of the battery at the same time. In addition, in the process of transporting batteries, the best way is to put each battery in a ziplock bag separately and place it in an explosion-proof box to prevent the positive and negative electrodes of a certain battery from touching at the same time due to bumps and collisions during transportation. To other conductive materials and short-circuit or break the skin and short-circuit.
6.Not in a cold environment
Maybe many flying friends will ignore this. There are often low temperatures in the north or high altitude areas. At this time, if the battery is left outside for a long time, its discharge performance will be greatly reduced. If you have to fly with the flight time at normal temperature, it will definitely cause problems. At this time, the alarm voltage should be increased (for example, the single-chip alarm voltage is adjusted to 3.8V), because the voltage drop will be very fast in a low temperature environment, and the alarm will immediately drop. In addition, it is necessary to heat the battery. Before taking off, the battery should be stored in a warm environment, such as in the house, in the car, in the incubator, etc. To quickly install the battery when taking off, and perform the flight mission. When flying at low temperatures, try to shorten the time to half of normal temperature to ensure safe flight.
At present, there are many brands and types of lithium batteries for model airplanes. You must choose the batteries that match your model's power needs to ensure the smooth operation of various electrical components. Don't buy some cheap triple battery, don't buy batteries to make your own batteries, let alone modify the batteries. If the battery is swollen, broken, or not fully charged, please stop using it immediately. Although the battery is a consumable, it provides energy to the aircraft. We should take time to value it, understand it, and take care of it in order to serve our every flight mission better and more safely.
Correctly maintain the battery and adhere to the "six essentials":
1. Regular inspection
Regularly inspect the battery body, handle, wire, and power plug to observe whether the appearance is damaged, deformed, corroded, discolored, or broken, and whether the plug is loosely connected to the aircraft.
2. Wipe the battery with a dry cloth
After each operation, wipe the surface of the battery and the power plug with a dry cloth to ensure that no other corrosive liquid remains to avoid corrosion of the battery.
3. Charging after the battery cools down
After the flight, the battery temperature is relatively high. You should wait for the flight battery temperature to drop below 40°C before charging it (the best temperature range for charging the flight battery is 5°C to 40°C). After the work is over, it is recommended to slow charge the battery for maintenance.
4.1C low current charging
That is, charge with a factor of 1 times the capacity. For example, the battery capacity of the drone is 12000mAh, which means it is charged with 12A current. Do a lower current (2A) balance charge once a week to ensure that the battery consistency is always in a better state. Of course, with such a small current, the charging time must be longer. When charging, you must ensure that the battery itself is at room temperature and charge in a cool place. The battery that has just been removed from the aircraft must be cooled before being charged.
5. Semi-electric storage
That is, the monomer is within 3.8V-3.95V. Storage environment: indoor temperature, it is recommended to put it in an iron box, which is safer. Lithium batteries that have not been used for a long time should be charged and discharged once within 3 months. Smart batteries should be charged and discharged once within 2 months.
6. Handle with care
This can prevent the battery from deforming or even catching fire due to impact. In addition, pay attention to holding the battery by the battery cable. The above maintenance measures can greatly increase the service life of lithium batteries, thereby reducing operating costs. Performing the above general methods of maintenance and maintenance of lithium batteries must be helpful to daily flight work.
