Tasel

This circuit will charge most lead acid battery with quickly and easily. A LED in the circuit as a monitor, which light when the battery fully charged an this circuit automatically switched off.

Parts:

R1___________500 Ohm 1/4 W Resistor
R2___________3K 1/4 W Resistor
R3___________1K 1/4 W Resistor
R4___________15 Ohm 1/4 W Resistor
R5___________230 Ohm 1/4 W Resistor
R6___________15K 1/4 W Resistor
R7___________0.2 Ohm 10 W Resistor
C1___________0.1uF 25V Ceramic Capacitor
C2___________1uF 25V Electrolytic Capacitor
C3___________1000pF 25V Ceramic Capacitor
D1___________1N457 Diode
Q1___________2N2905 PNP Transistor
U1___________LM350 Regulator
U2___________LM301A Op Amp
S1___________Normally Open Push Button Switch

Please add a heat sink for U1.

If you want to use the charger without having to provide an external power supply, use the following circuit.

Parts:
C1____________6800uF 25V Electrolytic Capcitor
T1____________3A 15V Transformer
BR1___________5A 50V Bridge Rectifier 10A 50V Bridge Rectifier
S1____________5A SPST Switch
F1____________4A 250V Fuse

[source:Aaroncake]