For some time I have used a battery back up pack for my ipod Classic whenever I am travelling and do not have power to recharge. This pack operates with 4 AA cells through the usual USB connection. It gives me around another 6 to 8 hours of power which is really handy.Add more AA cells and I can keep it going longer. My question is, if I wanted to use this method to back up my iPad (1st gen) power, would it be safe to use and not cause any problems to the internal battery of the iPad ? Or are there other issues involved which I need to take into account ?