Why the car drain battery

@prince60296 this could be related to a parasitic drain on your battery. That means that one circuit continues to draw power from the battery even when your Porsche is off. Of course, you hve to make sure that you have a good battery as well as a good alternator.

To check the battery you can use a multimeter. First check the (fully charged) batteries resting voltage (should be above 12.6V) by measuring between the positive and negative battery post. Vehicle not running of course. The battery should not be below that. Anywhere in the 10V is an automatic bad battery.

Next check the voltage while the engine is running (should be near13.8V−14.4V) that means your alternator is supplying the proper voltage to your battery.

The best way to test a battery would be with a load tester. That is a relatively inexpensive tool that positively identifies a bad battery.

After that, you do want to go and check for parasitic drain. It is not complicated but can be tedious. Checking for parasitic drain is the same for any vehicle, regardless of make and model. Of course the more circuits your vehicle has, the more tedious it gets. Use something like this video to check for anything that will cause your battery to drain.