The 12V battery automatic charging circuit will automatically monitor the battery voltage. When the battery voltage is lower than 11V, the circuit will automatically charge the battery until the battery is fully charged (about 14.4V ~ 14.7V). Coal Gas Generator,190 Series Coal Gas Engine,1600Kw Coal Gas Engine,Coal Gas Engine And Gensets Jinan Guohua Green Power Equipment Co.,Ltd. , https://www.guohuagenerator.com
At the same time, the charging circuit is automatically turned off after being fully charged, until the battery voltage is again lower than 11V, and the battery is recharged.
The circuit principle shows the circuit as shown. After the battery is connected to the circuit, because the base of Ql is connected with capacitor C1, and the battery voltage is less than 14.7V, then Dl and Ql are cut off, R3 provides base current for Q2, Q2 is saturated, and relay Jl is closed. The utility power is depressurized by the transformer T and is rectified by the full bridge to charge the battery. When the battery voltage is fully charged, the voltage will reach about 14.7V. At this time, Dl and Ql are turned on, Q2 is turned off, and the relay J1 contact is automatically disconnected. The charging is over.
After the charging is completed, the voltage of the battery will gradually decrease with the discharge of the load, and the resistance value of VR1 will be reasonably selected. Even when the battery voltage drops to 12V, D1 is cut off, but due to the existence of R2, Q1 continues to maintain saturation. Pass state, until the battery voltage continues to decrease until the current flowing through R2 to Ql is insufficient to support Ql conduction, Ql will immediately cut off, then Q2 saturates on, relay Jl pulls in, the mains is stepped down by transformer T and passes through the full bridge Recharge the battery after rectification.
The voltage regulator D1 is selected to be about 13.5V ~ 14V, plus the voltage across Rl and the BE junction voltage of 01 is exactly 14.4V ~ 14.7V, as the shutdown voltage of the charge monitoring, if there is no suitable voltage regulator can be used Two Zener tubes are replaced in series. VR1 is the charge-on voltage adjustment potentiometer. By adjusting VR1, the charge-on voltage is around 11V.
Component selection: Ql is C1815, β≥100Q2 is s8050, B≥100. 