Automatic Battery Charger Circuit Schematic Diagram

This circuit is used to fill up the accumulator. When the accumulator is already depleted, the current flows through D3 is low, therefore make the T1 off. IC1 output will be low, therefore T2 and T3 basis current will be determined only by P1 position.

If the accumulator voltage is between 10 and 14 volts, D3 will gain forward current and T1 will be ON. IC1 output stays low thus the filling process determined by P1 and P2. If P3 voltage exceed zener D1 voltage, with positive feedback through R4, the output of IC1 will go to the value determined by the voltage of Zener D1 and D2. As a result, T1 will be off and the filling process depends on the position of P1.Here is the schematic :

Automatic Battery Charger Schematic Diagram

Estimated price : $7

Component list :

R1 : 12k ohm
R2 : 10k ohm
R3 : 82k ohm
R5=R6=8k2 ohm
R7 : 100 ohm
R8 : 3k9 ohm
R9 : 4k7 ohm
P1 : 100k ohm, trimpot
P2 : 220k ohm-250k ohm, trimpot
C1a=C1b=4700 uF/40V
T1 = TUN
T2 : 8D138, BD140
T3 : TIP2955
D1 : 6V8, 400mW zener diode
D2 : DUS
D3 : 5V6, 400mW zener diode
IC1 : 741
Power transformator 16V/8 A
B : Bridge diode B80C 1.000
Slow fuse 1/2 A

Comments are closed.