CHARGING PROBLEMS

I HAVE A HONDA CRX 1989 ITS IN THE MIDDLE OF BECOMING A STREET RACER BUT MY PROBLEM IS I HAVE TO BOOST MY CAR EVERY TIME I WANT TO GO SOME WHERE ONCE ITS STARTED IT WILL STAY RUNNING I CHANGED BATTERYS WITH A NEW ONE AND IT STILL DEOES IT AND EVERY NOW AND THEN MY STEREO WIL TURN OFF ANBD RESTART BUT IT HAS TO DO WITH AWHAT EVER THIS PROBLEM IS BUT YA I DONT THINK IT IS THE ALTERNATOR BECAUSE IT STAYS RUNNING ONCE I BOOST IT UNTILL I SHUT IT OFF BUT THE SECOND I TURN THE CAR OFF THE BATTERY IS INSANTLY DEAD ANY IDEAS WHAT MIGHT BE WRONG THANX