I"m dum dum and do drugs all day long
Sorry I ate too many drugs at once and space time continuum hit me to hard. Sorry to all those participating in the conversation.
If the battery is discharged, then you will need some other source of power and some electronics, e.g. an Arduino or similar to provide the USB interfacing. Not sure how you conceived the connection between the magnet and discharged battery to actually store data. Perhaps that is an as yet undiscovered application of quantum uncertainty.
Are you saying a USB stick that can carry a charge so it acts like a battery?
How do the magnets help with the USB or battery?
How would someone get the data from the device?