12V charger schematic Top7 ranking, do you understand?
Circuit diagram of simple 12V charger (1)
Charging process analysis:
- Maintenance and charging:
When the battery voltage is low (can be set, this circuit is preset below 9V), the charger works in the state of low current maintenance charging, the working principle is that the potential of u-9 pin (in-phase end) is lower than that of U-8 pin (in-phase end), u output is low, and T4 is cut off. The potential of u1d11 pin 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 constant current principle is analyzed by itself)
- Fast charging:
As the maintenance charging continues, the battery voltage increases gradually. When the battery voltage exceeds 9V, the charger will switch to the high current fast charging mode. The potential of U (in-phase end) is higher than that of U (in-phase end). U outputs high potential, T4 is on, and the potential of u1d11 is about 0.48v. The charger will output about constant current to charge the battery.
- Pressure limiting floating charge:
When the battery is nearly fully charged, the charger will automatically switch to the limited voltage floating charge state (the limited voltage floating charge voltage is set to 13.8V, if it is 6V battery, the floating charge voltage should be set to 6.9v). At this time, the charging current will gradually decrease from the fast charging state to the fully charged battery, and the charging current is only 10 ~ 30mA, which is used to supplement the battery's power loss due to self discharge.
- Protection and charging indication circuit:
The circuit is equipped with reverse polarity protection circuit, which is composed of D4, u, u1d, T1 and peripheral components. When the battery is connected reversely, the charger will limit the output current to avoid accidents. The charging indicator consists of u, D7 and peripheral components. When charging, D7 lights up. When the charger enters the floating charging state, D7 goes out, indicating the end of charging.
Circuit diagram of simple 12V charger (2)
The circuit is a high performance charger for colloidal dielectric lead-acid batteries. The charger can charge the battery quickly, and when the battery is full, it can quickly disconnect the charge. The initial charging current is limited to 2A. With the increase of battery current and voltage, when the current increases to 150mA, the charger will adjust to a lower floating voltage to prevent overcharge
Circuit diagram of simple 12V charger (3)
As shown in the figure, the circuit is composed of 7805 constant current source circuit, which is expanded by high-power triode.
Circuit diagram of simple 12V charger (4)
Whether it's a low current (50 MA) or a high current (1 Amp), the circuit has the ability to provide. You can choose manual charging or automatic mode. When the current is very low, you can use low current before choosing high current charging. If the battery voltage is too low, the zener diode D5 will have enough current to generate a voltage across R6 to turn Q2 on.