Constant current self-stop 6-24v charger principle - Power Circuit - Circuit Diagram

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin.

MOS power IC full range.

Photocoupler.

The simple charger described in this article is capable of automatically charging batteries below 24V, with a maximum charging current reaching up to 2.5A. It features both constant current charging and an automatic shutoff function once the battery is fully charged.

As shown in Figure 4-9, the schematic diagram of the automatic charger demonstrates how the 220V mains voltage is stepped down by the transformer T to produce the secondary voltage U2. The VD1~VD4 rectify this voltage into DC with some ripple. The positive A point passes through the relay's normally closed contacts K1-2, resistor R4, ammeter PA, transistor VT1, and then through the battery GB to VT2 and finally to the negative B point for charging. By adjusting the size of RP1, we can control the base potential of VT1 and VT2, thus regulating the collector current Icb of VT2, which determines the charging current. Since the battery terminal voltage reflects its charging state, using a nominal 12V battery as an example, when the battery voltage reaches (12/2)*2.5=15V, VT3 becomes saturated and activates K1, disconnecting the normally closed contact K1-2 and cutting off the charging circuit, stopping the charger. The upper limit of the battery's full self-stop can be adjusted via RP2.