Why is lithium battery three lines, what is the role of each line?
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2022/07/21 17:40:42
Two possibilities!
1) If your battery does not have a protection plate, the three lines are: the red line is the positive pole, the black line is the negative pole, and the other color lines are the middle pole of the battery. These three lines are connected to the motherboard of your product, and the middle pole is for your product motherboard to monitor the voltage of the lithium battery.
2) If your battery has a protection board, the three lines are: the red line is the positive battery, the black line is the negative battery, the other color line is the NTC of the protection board (thermistor), thermistor is to detect the temperature of the lithium battery to the motherboard or distinguish the type of battery. Of course, you know this best yourself, and asking someone else is always a lot of answers, because your questions leave people guessing. Of course, in addition to these two possibilities will be much, much better. For example, one line is the equalization charging line of the battery, data signal line. Wait, if you know exactly where the three wires are connected, please tell me.
With the decline in the price of lithium batteries, many fields on the market now began to use lithium batteries to replace the original lead-acid batteries, nickel-metal hydride batteries, etc., due to the activity of lithium ions, the use of lithium batteries must be protected with a protective plate, to prevent lithium batteries from overcharging.
Schematic diagram of wiring Principle
☆ Special attention: the wiring of different manufacturers is not common, please make sure to use the supporting wiring: ① Before connecting the wiring, make sure that the wiring is not inserted into the protection board; ② Weld the protection plate B- line (thick blue line) to the total negative electrode of the battery; (3) Starting from thin black wire connecting B-, the second wire (thin red line) is connected to the positive pole of the first string of batteries, followed by the positive pole of each string of batteries, until the last string of B+; ④ After the line is connected, the plug should not be directly inserted into the protection plate, measure the voltage between each two adjacent metal terminals on the back of the plug, if the terpolymer battery voltage should be between 2.8~4.2V, iron lithium battery should be between 2.5~3.65V, lithium titanate battery should be between 1.6~2.8V; ⑤ After confirming the wiring sequence and voltage, insert the protection plate into the socket
After wiring is completed: measure the battery B+, B- voltage and P+, P- voltage is equal, equal to the protection board normal work, can be used normally. If not, please check again according to the above wiring sequence. PS: the method of connecting this line is the same with the port and the port, the difference lies in their discharge connection (load, motor) and charging method is not the same. The negative electrode of the same port charge and discharge is connected to the P- line; Parting is the charging line is connected to the C- line, discharge is connected to the P- line.
1. By pressing the B-line terminal and the B1 line terminal with the black multimeter pen, the voltage of the first battery is 3.584V.
2. By pressing the B1 wire terminal with the black multimeter pen and the B2 wire terminal with the red multimeter pen, the voltage of the second series of batteries is 3.584V.
3. Through this method, it can be concluded that:
The first battery voltage: 3.584V
The second battery voltage: 3.584V
The third battery voltage: 3.585V
The fourth battery voltage: 3.585V
The fifth battery voltage: 3.583V
The sixth battery voltage: 3.583V
The 7th battery voltage: 3.584V
The 7 series voltage is 3.58V, the wiring is correct, and the battery voltage difference is less than 0.002V, the battery consistency is good.
By connecting the B- wire, measure the voltage of B- and the total positive terminal of the battery and the voltage of P- and the total positive terminal of the battery
If the voltage is consistent, it indicates that the protection plate is normal (the protection plate is equivalent to a switch, which has been opened and the current can pass safely).
Sample test results:
The total positive voltage from B- to the battery is 25.11V
The total positive voltage from P- to the battery is 25.11V
If the two voltages are consistent, the protection board is normal. If P- discharge through a large current, there will be a slight voltage drop, the protection plate heating (about 50 degrees), which is a normal phenomenon.
Make sure that the wiring is correct, because wrong wiring will burn the protection board, so double check the voltage of each battery string by voltage to ensure that the wiring is correctly connected.
If it is old batteries, battery voltage of each string is greater than 0.1 V, big differences of battery series is likely to have electricity, in the changes of capacitance and resistance, forming a barrel short board effect, cause the charging overcharge protection, discharge too quickly as the overcharge protection, simple to understand is the battery life is short, electric cars and other application scenarios using time is short.
Protection plate is to protect each string of batteries, any string of overcharge or overdischarge will cause protection. If it is 4s lithium battery, it is 0, 3.7, 7.4, 11.1, 14.8, five different potentials. If it is a protected version, the red two and black two should be internal short, lead the two to increase the current. White is the symbol bit of the protection chip. After protection, it is the high battery, and when not protected, it is the low level. Lithium battery has 5 wiring, two red, two black, one white, all kinds of what definition?
Three-phase voltage instability causes fever and even burning motor, because of the three-phase motor is balanced three-phase load, namely each phase load impedance are equal, the power supply for the symmetric three-phase voltage, load current flows through each phase are equal, but asymmetrical three-phase voltage, the flow through each phase of load current is not equal, and a phase electricity flows to high load (may be far more than ratings), accordingly The phenomenon you describe occurs.
A two-wire DC motor is one in which the circuit is connected internally (such as shunt motor) or requires only two wires (such as toda); One of the three wire DC motor is the common line, and the other two are the armature and the excitation line respectively (such as the series motor of the electric tricycle).
First the nimH battery charger is charged by pulse! The voltage is around 1.5V! But the 18650 lithium battery needs to be charged with 4.2V constant current and constant voltage! You can change it with a phone charger!
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