Regarding to the advantages of lithium batteries—fast charge and discharge speeds and high energy per unit weight,Lithium batteries are more popular now in the market. And for users, the correct use and charging of lithium batteries is very important. How to use lithium battery safely ? Following is GSLIBATT company suggestions form our engineer:
First, charge safety
If you are always careless or too lazy to follow a variety of safe use rules, then you’d better give up using lithium batteries.because the most dangerous process for using a lithium battery is charging, not only using a dedicated charger, but also correctly setting the voltage and the number of battery cells, otherwise it may cause a fire.
Lithium batteries is different from VRLA batteries ,lead acid batteries , gel AGM batteries , nickel-cadmium batteries and nickel-metal hydride batteries based on charging methods, it requires a dedicated charger. In general, as long as the number of battery cells is set, the charger for lithium ion battery can also charge the lithium polymer battery. But do not use nickel-cadmium batteries, VRLA batteries or nickel-metal hydride batteries chargers to charge lithium batteries. The consequences would be very dangerous.
Lithium battery charging guidelines:
1. Use a charger that matches the lithium battery. This charger is designed specifically for lithium batteries, and its price is not expensive.
2. Be sure to set the number of battery cells correctly (Figure 2). at the begining of charging,it is also necessary to observe from time to time whether the number of battery sections displayed on the charger is always correct.
3. Before charging a newly purchased lithium battery, check the voltage of each battery. This operation should also be performed after every ten times of charge and discharge. This step is very important because unbalanced lithium batteries are prone to fire when charging. If the voltage difference between each battery exceeds 0.1V, each battery should be charged to 4.2V. If there is an imbalance before each charge, it indicates that a certain battery has failed and needs to be replaced.
4. The entire process of charging the lithium battery cannot leave supervision . The frequent accidents that caused the charging of various lithium batteries to cause fires in houses and cars occurred without supervision.
5. It is best to charge in a safe area with no inflammables, such as a thin layer of ceramic plates, pots, etc. (figure 5). In the event of a lithium battery burning, it will not cause a fire.
6. Do not charge at more than 1C unless otherwise noted in the product specification. Although theoretically the battery can withstand high rate charging , it would still shorten the battery life and increase the probability of fire risk. If you really need to, buy a few more batteries for replacement,so you would not rush to charge.
7. Do not hit the lithium battery. Do not use the lithium battery if it is bulged. Place it isolated from flammable materials for more than two hours. If there is no danger, use a flashlight bulb (rated voltage higher than the battery voltage) to connect the positive and negative electrodes of the battery to discharge. After the light of the light bulb is completely dimmed, the battery can be removed and thrown into the sort bin.
8. In the event of a "demolition", the lithium battery would be damaged. Even if the appearance appears to be intact, there may be a partial short circuit inside due to the impact. At this time, the lithium battery should be immediately removed from the model and placed on an insulating flammable place for more than 20 minutes to eliminate the fire hazard. There was once a user throwing the damaged battery directly in the car, causing the fire to ruin the entire vehicle and regret it.
9. To charge in a well-ventilated place. Because if the battery burns, it will produce a lot of harmful gases that can quickly dissipate in well-ventilated areas.
10. Prepare a special lithium battery fire extinguisher or prepare a small bucket of sand (Figure 9). In this way, in the event of an explosion of a lithium battery, it can be quickly and effectively extinguished.
11. A fire can happen to anyone, and it's often a pittance to pit yourself. Use lithium batteries carefully to avoid any safety hazards.
Second, lithium battery knowledge
1. What is a lithium battery
Lithium batteries are widely used in various electronic devices: mobile phones, laptops, PDAs, etc. Lithium batteries are not aircraft model-specific technologies. Lithium polymer batteries and lithium-ion batteries have in common - the same voltage 3.6V. There are also different points. Lithium-ion batteries are housed in a metal case, and lithium polymer batteries are in flexible packages. The common lithium polymer battery is a square wafer shape with positive and negative tabs. Its outstanding advantage is its light weight and it is very suitable for use in aviation models.
2. Voltage and battery section
After the lithium battery is fully charged, the voltage is 4.2V, and the voltage after the discharge is 3.0V. When using, the two limit values cannot be exceeded, otherwise the battery may be damaged.
The specific method to avoid the lithium battery voltage below 3.0V is to set the minimum voltage in the electronic governor. When the voltage of a single battery is lower than 3.0V, the manipulator will get feedback from the sudden drop of power, knowing that it is time for the model to land. If the electronic governor has an automatic lithium battery mode, it can automatically determine the number of battery cells and automatically set the limit voltage.
3. What is 10C? What is 3S4P?
The battery discharge rate can be measured in C. 1C means that the battery is fully discharged in 1 hour, and 2C means that the battery is fully discharged in half an hour. The discharge time is the inverse of the C number. The battery power is measured in milliamperes. For a 2 000 mAh battery, if it is charged at 2 000 mAh, it will be charged in one hour. There is a concise mathematical relationship between battery capacity, C number, and discharge current. A battery at 2 000 mAh, if discharged at 1 C, the discharge current is 2 000 mA×1=2 A; if it is discharged at 3 C, the discharge current is 2 000 mA×3=6 A.
All battery discharge rates are limited. For this reason, several lithium batteries are often used in parallel to obtain larger currents. In parallel connection, the positive electrode and the positive electrode of the battery are connected, and the negative electrode and the negative electrode are connected. If you connect two lithium batteries in parallel, you get twice the original current. When two lithium batteries with 2 000 mAh are connected in parallel, they are equivalent to a lithium battery at 4 000 mAh. The C number is the same as the original, and the rated current is doubled. In other words, if the original battery can discharge at 5C and 10A, it can discharge at 5C and 20A after being connected in parallel. Model Friends usually use this method to get a larger discharge current.
The xSxP naming method clearly expresses the number of batteries in series and in parallel. The number in front of S is the number of batteries in series, and the number in front of P is the number of batteries in parallel. Lithium batteries at 3S4P and 2 100mAh represent 12 batteries. Assuming that the discharge rate is 6C, then the voltage is determined by the number of series cells 3, and the discharge current is determined by the number of parallel cells 4. Therefore, the battery's rated voltage is 10.8V (3 × 3.6V), and the maximum discharge current is 50.4A (2 100mA × 6 × 4).
4. Purchase battery
Compare the list of performance parameters when you purchase the battery. Lithium batteries of similar size and weight will have different voltage characteristics when discharged at different currents, and batteries may be purchased accordingly. If you feel that the list of performance parameters is too cumbersome, you can also refer to others' successful experiences or ask GSLIBATT engineer ,we would give you the best suggestions. The classic collocation of model airplanes, engines, and batteries is very valuable.
Learning and understanding basic electrical knowledge such as voltage, power, and current will not only facilitate the purchase of suitable batteries, but also make the flying model of the electric model more interesting and successful.
Is the 30C battery better than 10C or 20C? This is not the case. The discharge rate does not necessarily increase as much as possible. To know that the battery discharges at 20C means that it will be dead for 3 minutes and the time is too short. For model helicopters, it may be more useful to have a large discharge rate, and when it is needed, it will be able to explode very strongly, but the significance for fixed-wing model aircraft is much smaller. Relatively speaking, 8C ~ 10C discharge rate is more appropriate.
The last advice, do not just want to be cheap. For a price, you must choose a reliable battery with a sufficient discharge rate. Because the consequences of operating at a current exceeding the standard discharge rate are severe, not only can the battery be damaged, but it can also damage other electronic devices.
5. About temperature
Lithium batteries are sensitive to temperature, and they can perform their own performance in the right temperature range. When flying in the field in the winter, you should try to put the lithium battery in the compartment or in the pocket of your personal clothes. In short, think of ways to maintain proper temperature. On the other hand, the temperature of a lithium battery is too high. To avoid the lithium battery reaches 70 °C after use to extend its life.
To conclusion,lithium battery is a good replacement for lead acid batteries, but you should know how to use it ,hope the above advices would helpful for you . If you have need lithium battery and lifepo4 battery, please leave us messages on our web. Thanks in advance.