12v charging circuit?

Hi everyone.

I need a 12V power in my project which will be at about 2A and I prepare to use a battery pack from laptop. The battery pack is 6 18650 batteries and it's 3 and 3 in series.

Is there any circuit I can find to use the pack as a constant 12V power and to charge the pack?

Thanks.

For power supplies in you projects go to Ebay and search step or step down as needed.
Then search for the current rating you need.

Also look at Pololu. Pololu - Step-Up/Step-Down Voltage Regulators