New alternator new battery but battery still not keeping charge what else could it be

I would also check the charging voltage and current with the car running. Take it to someplace like AutoZone and ask for a charging system load test.

It could also be what's called "parasitic drain". Something stays on after you turn the car off and take the key out. My favorite preliminary test is with a test light. Disconnect negative cable from battery. Clip the wire from the test light onto the battery (-) terminal and put the pointed end into the cable near the terminal (between the wires, trying not to peirce the insulation). If there is a parasitic drain, the test light will glow brightly. Unplug a fuse and see if the light goes dim or turns off. If not, plug that fuse back in and pull the next one. Repeat until you pull the fuse that makes it go dim or off. That's the circuit you have to check. Keep in mind that even with the key OFF, the car still has some memory functions that will draw some current, but only about 500 milli amps or so. Shouldn't be enough to kill a battery for at least a month. Also, when you find and repair it, your computer will have to go through the relearn cycle.

What do you mean not keeping charged ? Battery goes dead over night ,while driving the vehicle ? Could have a parasitic drain on the battery while vehicle is parked . Do you come out to start the vehicle in the morning an the battery is dead ?