Maximum current is about 650 milliamps. The circuit is designed for batteries of 900mah or higher. Power source can be a 12v Gell cell (Power panel), or can be powered by a car's cigarette lighter.
I use an old 12v DC wall transformer (800ma or more.)
Step 1: The Schematic
LM317 variable regulator
2N2222A or any Transistor handles 800mA
2 Capacitors 0.1 uf
1ohm 1Watt resistor ( current limitor )
Adjust R4 to the required output voltage
R1 controls the output current
Step 2: The PCB
and easy .
Using HP Glossy paper and Laser printer gives a good results
Step 3: Final Step
i have used a small heat sink for the LM317 in case of charging a bigger batteries.