The Teensy's need permanent labels showing their serial number

[JimsterCoder]

The serial number is used by BatteryController to identify the teensy and hence the batteries connected to it. If one were need to be replace in a hurry, it would be easier if the number was shown on it (the new one)

[NiallDarwin]

So we need a label printer? Ooo, we're grown up and real now!