not long ago i bought a mophie juice pack air case (external battery case) and i have noticed that the charging port (micro usb) is very delicate when using the usb cable that it came with (has a lot of play). When i use other micro usb chargers it seems very robust and fits well with no play. this is all well and good but i am not sure whether it is safe or not to go against the instruction manual and use a non-apple charging adapter. can anyone help me???