There is a problem with the charging system. Looks like the alternator is bad. Don't drive the car in this condition, when the battery drains you will stuck. Call a tow truck and get it towed to a shop.
this means there is a problem in your altenator, there is a rectifier or diode assy that is letting power flow the wrong way wich inturn turns on the battery light, or maybe the internal voltage regulater is bad