Because of the many advantages of sealed lead-acid batteries, it has been widely used. However, the charging technology of sealed lead-acid batteries does not seem to be valued. It is common for batteries to be prematurely scrapped due to unreasonable charging methods. In view of this, the author designed and produced a two-stage constant current limiting voltage lead-acid battery charger.

Analysis of charging principle:

1. Maintenance charging: When the battery voltage is low (can be set, this circuit is preset below 9V), the charger works in the small current maintenance charging state, the working principle is U1C9 foot (in-phase terminal) potential is lower than 8 feet (inverting terminal), U1C outputs low potential, T4 is cut off. U1D11 foot potential is about 0.18V. At this time, the charging current is about 250mA (the constant current circuit is composed of peripheral circuits of R14, U1D, and T1B, and the reader of the constant current principle should analyze it by itself).

2. Fast charging: As the maintenance charging continues, the battery voltage gradually rises. When the battery voltage exceeds 9V, the charger turns into the high current fast charging mode, and the U1C9 pin (in-phase terminal) potential is higher than 8 feet (inverting end) ), U1C output high potential, T4 is on, U1D11 pin potential is about 0.48V, the charger constantly outputs about 1A current to charge the battery.

3. Voltage-limited floating charge: When the battery is close to full charge, the charger automatically switches to the voltage-limited floating charge state (the voltage-limiting float voltage is set to 13.8V. If it is a 6V battery, the float voltage should be set to 6.9V), the charging current will gradually drop from the fast charging state, until the battery is fully charged, the charging current is only 10 ~ 30mA, to supplement the battery lost due to self-discharge.

4. Protection and charging indication circuit: This circuit is equipped with reverse polarity protection circuit, which is composed of D4, U1C, U1D, T1 and peripheral components. When the battery is reversely connected, the charger limits the output current without causing an accident. The charging indication is composed of U1A, D7 and peripheral components. When charging, D7 lights up, and after the charger enters the floating state, D7 goes out, indicating that charging is over.

Many people have this feeling. When the mobile phone charger is charging the mobile phone, it often feels that the fever is very serious. What is the situation? Currently, Android phones on the market are unified charger jacks. Any Android phone charger can charge the phone. Although the display is charging and can be charged, not all chargers are unified. There are actually many differences between them.

The Android mobile phone chargers on the market are generally around 5v, but the charging current of different chargers is different. When charging with a small rated current, the speed will be much slower, and charging with a charger with a large rated current will be used. , the speed will become faster. There are two reasons why the mobile phone charger is hot. One is that the charger socket does not completely match the mobile phone, causing the charging to be unsmooth; the other is that the current of the charger does not match the current of the mobile phone, forming a charging obstacle.

The current mobile phone chargers have been similar, and the charging time of the smart phones is relatively short. It is not necessary to tangled whether it is the original charger, which is not a big problem for mobile phones.

Everyone should understand that when a metal component is over-powered, part of the electrical energy is converted into heat. This is a normal phenomenon, unbelief can be Baidu. And how much heat is related to voltage, current, and resistance. If the voltage and current output by the charger are relatively large, the charging time is shortened, and there is a transformer component inside the charger, so the heat of the charger itself is normal.

Typical chargers are 500ma, 750ma, 1a, 1.5a, 2.1a. These chargers charge at different speeds, and the speed of charging is different. The higher the current, the faster the charging and the more obvious the heat. You can experiment on your own and record data such as heating temperature and charging time. At present, the standard of mobile phone charging interface has been basically unified, but the power adapters of different brands of mobile phones are not unified, and the technical indicators such as current are not the same. When charging a mobile phone, it is best to use the original charger or use a well-known and well-known brand charger.

The charger plug is plugged into the 220V AC socket. After the mobile phone is connected to the charger through the data line, the 220V AC power is first converted into high-voltage DC power through the rectifier circuit, and then converted into a high-frequency high-voltage pulse through the switch tube, and then converted into a low voltage through the transformer. (such as 5V) pulse. The 5V low-voltage pulse passes through a rectification and voltage-stabilizing circuit to become a 5V stable DC power. This is the process of charging the entire phone.

1. If the user is using the mobile phone, the mobile phone has a fever. If you feel worried, you can place an ice pack on the back to cool the mobile phone.

2, but be careful, because the ice pack will produce a lot of condensed water at room temperature, do not rely on the phone too close, so as not to cause the phone to enter the water failure.

3. It is recommended that users try to wrap the ice pack with a towel and then try to cool the phone.

There are several reasons why the phone charger is not in good contact.

1, you did not insert, the solution is to re-plug and try.

2, the charger has a problem, and the charging jack is not in good contact, the solution is to try another charger.

3, the charging jack has a problem, resulting in the connection with the charger or poor connection, the solution is to go to the repair shop, repair the charging jack. If there is a problem with the charging jack, I personally recommend not to fix it, because that is connected to the motherboard, be careful to be repaired.

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