Q: How far can I drive with my Battery Light (including my brake lamp) turning off a minute ago. I am aware my brake pads are gone

The usual cause for a battery light to come on is a fault in the charging system. If the alternator is not charging and providing electrical power, then the electrical system will resort to draining the battery for power. Since the alternator may not be providing power, the vehicle may only run until the battery is drained. There is no way to determine how long that can be as factors like what electrical accessories are being used (lights, heat or A/C, etc.) will drain the battery more quickly. Have a certified technician diagnose the Battery Light and brakes so that this can be addressed appropriately.