Can I give you an advice! Grab a multimeter, set to DC and check the battery for voltage, should be 12 volts DC, if you have already replace the battery no too long ago or less than 6 months then check for alternator. How to! Start the car, check again for voltage, while the car is running the voltage should be between 13 or 14 volts, if is not then you have a bad alternator. That’s why your battery still going bad. Or. if it is 13 to 14 volts then you have a short circuit in your car, maybe is your radio or lights that is sucking juice out of it. Also check for fried wire in your engine compartment maybe is producing short circuits. If you can’t find any problems then consider taking it to the mech. Good luck.