Battery keeps going dead - 2011 Hyundai Tucson

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 ?

Does it go dead after sitting for a few hours? Once started and driven for several miles will it restart if the engine is shutoff? If the battery goes dead only after sitting for a while with the engine off, you probably have a bulb or some accessory that is draining the battery.

possibly a draw on something maybe a light stays on when you park it..? gloive box light ,door light could be a lot of things if you put a test light between the ground cable and the battery and hook up the positive battery cable ther should be very little to no light ifit is bright then you have someting drawing power

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.

check ur alternator