Car Battery Charger

This charger will quickly and easily charge most any lead acid battery.
The charger delivers full current until the current drawn by the battery
falls to 150 mA. At this time, a lower voltage is applied to finish off
and keep from over charging. When the battery is fully charged, the
circuit switches off and lights a LED, telling you that the cycle has


This is the schematic of the Car Battery Charger


Total Qty.
R1 1 500 Ohm 1/4 W Resistor
R2 1 3K 1/4 W Resistor
R3 1 1K 1/4 W Resistor
R4 1 15 Ohm 1/4 W Resistor
R5 1 230 Ohm 1/4 W Resistor
R6 1 15K 1/4 W Resistor
R7 1 0.2 Ohm 10 W Resistor
C1 1 0.1uF 25V Ceramic Capacitor
C2 1 1uF 25V Electrolytic Capacitor
C3 1 1000pF 25V Ceramic Capacitor
D1 1 1N457 Diode
Q1 1 2N2905 PNP Transistor
U1 1 LM350 Regulator
U2 1 LM301A Op Amp
S1 1 Normally Open Push Button Switch
MISC 1 Wire, Board, Heatsink For U1, Case, Binding Posts or Alligator Clips For Output


  1. The circuit was meant to be powered by a power supply, which
    is why there is no transformer, rectifier, or filter capacitors on the
    schematic. There is no reason why you cannot add these.
  2. A heatsink will be needed for U1.
  3. To use the circuit, hook it up to a power supply/plug it in.
    Then, connect the battery to be charged to the output terminals. All you
    have to do now is push S1 (the “Start” switch), and wait for the
    circuit to finish.
  4. If you want to use the charger without having to provide an external power supply, use the following circuit.

    This is the schematic of the Car Battery Charger Power Supply

    Total Qty.

    C116800uF 25V Electrolytic Capcitor
    T113A 15V Transformer
    BR115A 50V Bridge Rectifier10A 50V Bridge Rectifier
    S115A SPST Switch
    F114A 250V Fuse

  5. The first time you use the circuit, you should check up on it
    every once and a while to make sure that it is working properly and the
    battery is not being over charged.

Sorry, comments are closed!