Battery Pack

How to attach a charging circuit or device to 12v 10000mah battery pack (1.2v AA battery X 50)?
So that it is no need to disassemble the whole battery pack and charge 50 pieces of battery 1 by 1.
Am i too late to answer ?? I think you must arrange the batteries in a serial and parallel stack.If you wish to use a 12v charger device,you must arrange some batteries in serial connection so the total voltage of the batteries stack will be 12 v,so every 10 batteries stacked in series.(10 x 1.2v = 12v).Now you have 5 stacks (consist of 10 batteries in serial).Then,arrange these 5 to parallel connection. Now you can attach the charger device to the batteries stack.
Zapper Battery Pack install