Multi-speed constant current charger circuit

The circuit structure is simple and has good performance. It can charge 1 to 10 12V
batteries of the same specifications simultaneously after being connected in series. The charging current passes through the switches S]~S. You can choose between 1-15A. Once the current
is selected, it can be kept constant and will not be affected by grid voltage fluctuations and load changes, eliminating
the trouble of adjusting the electric sulfur during the charging process; the output end is not afraid of short circuit, even if Even if the output terminal is short-circuited and run for a long time, the rectifier diode and other components will not be damaged
, so the reliability is very high; the power consumption is low, the heat generated by the whole machine is small, and the internal temperature is low during operation.
    The inductor L can be made of a double wire of 1.5mm enameled wire and wound with 32 turns to make an air-core coil with a diameter of 120mm.