First check the battery
Check the charging system
Then start looking for a current draw, should be around 0.03 amps @ rest, ign. off for over 20 mins is the best time to take a reading at rest, as you can be sure all the systems are shut down.
If you have a current draw over 0.03 amps then it's a case of illimination, the easy way is pull the fuses one by one, until the current draw is eliminated, start with things like boot lights and radios and any aftermarket extras fitted Bluetooth, sat nav, alarm ect. if it's still there maybe a fault in the altenator, short in the engine ecu.
but it's a new car get a dealer to fix it !
hope this helps
