Is hair charging normal? Basic introduction of universal charger
Universal charger can charge many types of rechargeable batteries, mainly mobile phone batteries, and can charge almost all mobile phone batteries, so it is called universal charger. On June 14, 2007, the Ministry of Information Industry (now renamed as the Ministry of Industry and Information Technology) promulgated and implemented the "Interface Industry Standard for Mobile Phone Chargers", hoping to unify the standards of mobile phone chargers in one fell swoop and let consumers manage a charger for life. This good expectation has not been generally recognized by the market so far. However, in 2003, the universal charger invented by Chen Tianhan, a senior two student of Zhengzhou No.1 Middle School in China, fulfilled the wishes of hundreds of millions of mobile phone users in China ahead of schedule. This simple design, two adjustable metal contact shrapnel and a transparent clip for fixing the battery have become essential accessories for tens of millions of mobile phone users in China.
Because of the volume limitation and cost saving, it is impossible to increase the protection circuit in the voltage stabilizing part of universal charging. Secondly, the protection circuit of the original mobile phone charger is well designed, such as matching the charging current according to the battery capacity. When the charging temperature rises, the resistance of the thermistor changes, forming a loop with the charger to adjust the charging current and prevent overheating. No matter whether the battery capacity is 600mAh or 1000mAh, no matter how the battery temperature changes, the universal charger always charges the battery with a fixed current. So charging for a long time will increase the battery temperature. When the temperature is high, it will have a great impact on lithium batteries, and high-temperature charging will often damage the batteries.
Working principle of universal charger
When the universal charger works normally, the input voltage is 220v AC and the output is 4.2 ~ 4.3v DC. According to the voltage difference between the universal charging output voltage and the rechargeable battery, the rechargeable battery voltage is about 3.7V. During the charging process of rechargeable battery, the voltage will rise slowly with the increase of battery capacity. When the voltage of rechargeable battery approaches the general charging output voltage, the charging current will gradually drop to zero. When the voltage of the rechargeable battery is equal to the universal charging output voltage, the charging stops. The intelligent universal charger limits the charging current to avoid damage to the rechargeable battery caused by excessive charging current. The intelligent universal charger also has the function of automatically stopping after charging. When the battery voltage reaches a certain value during charging, the universal charger automatically stops charging, which plays a role in protecting the battery and avoids the danger of explosion caused by overcharge of the battery.
Is the charging process of lithium battery constant current? Constant pressure? A trickle replenishes electricity. The first is constant current charging, that is, under the condition of constant current, the battery voltage rises step by step with the charging process. When the battery voltage reaches 4.2V, it changes from constant current charging to constant voltage charging, that is, under the condition of constant voltage, the current gradually decreases according to the saturation of the battery cell. When the current decreases to a certain extent, the charger thinks that the charging is over, and then trickle charges the battery with a small current. Many general-purpose batteries change the charging cut-off voltage to 4.2~4.3V in circuit design, that is, after the battery voltage reaches 4.2V, they will continue to charge the battery with a fixed current until the battery voltage reaches the set value.
Then charge the battery with a fixed current and a fixed resistor? Leak? There is a current coming out, and this current is fixed. Plug in the battery and it won't stop. So the battery is fully charged. So some friends will think that the original charger has a longer battery life than the universal charger. However, the damage of overcharge to lithium battery is very serious, and the performance of battery will decay rapidly after long-term use. Therefore, friends who use universal charging for a long time will find that the battery is swollen after a period of time, and the battery life is not as good as before, precisely because of overcharging with universal charging.
How to use universal charger
Fixed battery:
Adjust the position of the metal contact according to the distance between the anode and cathode of the battery, so that the contact with the battery position is correct and the metal contact with the battery electrode is good. For lead batteries, directly insert the lead plug into the corresponding jack.
Polarity confirmation:
What if the battery is red after installation? Polarity? The warning light is on, indicating that the positive and negative poles of the battery do not correspond to the contact electrodes, and must be dialed? Switch? Do polarity conversion until red? Polarity? When the warning light goes out, it means that the polarity connection is correct.
Charging confirmation:
After the polarity is confirmed, turn on the power. Power supply? The light is on, and at the same time? Charging? A red light indicates a charging state. (Note: If it appears at the initial stage of charging? Charging? The light doesn't work, only? Power supply? With what? Saturation? The light is on. This phenomenon is mostly caused by poor contact or wrong contact between battery electrode and contact electrode. Repeat one or two steps to correct until? Charging? The red light is on, and it enters the normal charging state. )
Charging complete:
Saturation when the charging indicator lamp is completely extinguished? When the indicator light is fully lit, it means that the charging has been completed. The extension of charging time does not affect the use effect of the battery. The charger has the function of over-current and over-voltage protection, has an accurate battery state detection circuit and can automatically adjust the charging current to protect the battery. )