I've had this mod for about 3 months , recently the micro usb charging port has stopped working and now my mod heats up passively when the batteries are in, the batteries are all pretty new and have new sleeves on them so my question is: is this normal or does this mean that there is an internal shortage occuring in the mod causing the display and essentially the motherboard (i assume thats what is heating up) to heat up even if i am not actively vaping the mod... my tank remains cool and the batteries seem relatively cool too