My battery keeps going dead on me wat can it be

Instead of continuing to purchase batteries and alternators, why don't you take your car to a qualified mechanic and have it properly diagnosed and repaired. It certainly would be cheaper.

Your battery may have a dead cell,take it to Autozone and let them test it,it's free,also make sure your battery cables are good and make a tight connection to the battery terminals.

Sounds like a slow drain - like a dome light or short in the wiring.
If the battery stays charged when it is disconnected, you'll have to check for a power drain in the car.

you have a drain somewhere....check boot light or bonnet if you have one.Clean and tighten terminals.Most common is alternator diode but maybe something simpler.

Diagnose the door lock issues first,that you know is a problem

Why would you replace the alternator ?

because you are going back to a dealer
take it to an accredited auto electrician and have the electric system checked properly instead of guessing the fault

Have you checked to see if the alternator is charging ? Run a volt meter on the battery with the engine running, have to have more than 14 volts. If 13 or less, then replace the alt.

With the engin not running and the key off, lift the hood and disconnect the positive lead on the battery. Then touch the lead back to positive terminal on the battery. If a spark is seen, there is something still on in the car. Could be the power mirror switch, seat heaters or even a car phone. Trial and error to find it.

Sorry I can't be more specific but that is the test.

Good luck.

Well, if the alternator belt squeaks a little, it cannot be actually charging properly, resolve that...

First steps would be to fully charge the battery and measure the voltage. Turn of vehicle Disconnect the negative terminal overnight, for a night or two.

If battery still dead, focus on the battery.
If battery is not dead, put a volt meter between the negative terminal and cable and measure voltage... do not be mislead by interior lights, or clock, pull those fuses, during testing...

Anyways, keep going until you find a drain.

The alternator has diodes that can cause a drain...disconnect for testing purposes...

NEVER run the vehicle with the battery cable dicsonnected.

Doc

check ur alternator