Manufacture of Lead Battery Charger

As shown in the figure, when the "" - "pole of the battery to be charged is connected to the circuit, first turn W1 to the bottom, then turn on the power switch, then press the an button, JA acts, and ja-1 is pulled in and locked; Ja-2 connect the charging circuit. Take 36ah lead storage battery as an example. Slowly adjust W1 to change the oscillation frequency of bt33, so as to change the conduction angle of unidirectional thyristor. Make the pointer of the ammeter about 1.8A. At this time, the charger charges the battery. With the increase of charging time, the charging current gradually decreases and the voltage at both ends of the battery gradually increases. When the voltage at both ends of the battery is 16V, JB acts and JB-1 disconnects the 220V power supply circuit; JA is released, ja-1 is unlocked, ja-2 disconnects the battery and detection circuit, and the charger stops working.

The safe charging current of the battery is generally 1 / 20 of the capacity. For example, the charging current of 36ah battery is about 1.8A. In order to make the charger universal, the power of the transformer should be larger and the output voltage should be higher. I choose the secondary output 10A / 24V transformer, which can charge the battery below 150Ah. 20A / 200V silicon stack for rectifier and 20A / 200V unidirectional thyristor. The contact current of JA relay is greater than 10a, and that of JB relay and button is greater than 5A. The integrated circuit LM324 is better than the LM741, and the genuine 74l products on the market cannot be bought. When the defective output pin does not act, there is a voltage of about 1.3V. The resistance is 1 / 2W, others are shown in the figure, and there are no special requirements.

The element is fixed in a metal casing made of iron sheet, and the volume depends on the size of the transformer. The current meter, voltage meter, power switch, button, charging "", "-" pole terminal and current adjustment potentiometer W1 are installed at the appropriate position of the front panel, and the fuse and power line lead are installed on the rear panel. Heat sink shall be installed for rectifier silicon stack and unidirectional thyristor. The components can be debugged after being welded on the copper clad plate of the universal circuit and connected correctly according to the circuit diagram. An external 16V power supply is used to supply power to the voltage comparator centered on the operational amplifier LM324. Adjust W3 to make the relay JB just act. The adjustment of the protection circuit is completed. Find a 150Ah lead-acid battery to be charged, connect it for charging, and slowly adjust W1 and W2, that is, adjust W1 to increase the charging current and W2 to reduce the charging current. When W1 is adjusted to the maximum, the charging current is 7.5A, so that the charging current is less than the operating current of the transformer. After adjustment, replace W2 with a fixed resistance close to the adjusted resistance.

4 Note that W1 must be turned to the left before charging; When charging, the battery cannot be connected reversely: slowly adjust the charging current; Turn off the power switch at the end of charging.