Mine is only 3k miles, 7 months old.

It's really frustrated me. 3 weeks ago, first time I went to dinner and came back 1 hour later just to see the battery was completely dead. All alert *ABS, brake, light on screen came up. Have to call RSA for jump start
2nd time, same thing happen overnight. Battery drains for no reason
Came to maintenance, dealer said everything is fine
3rd time, same thing all over again.
I don't know what to do. Will go back to dealer to force them at least replace my battery.
Anyone know what happen with the car? Is that the battery or something else? I researched a bit and found out it may relate to the AC relays fail.

 

Probably it is some relay that is sticking closed, leaving something in the car powered up when the car is off. But it might be a relay that sticks closed intermittently, so that the dealer didn't see it when they checked. (Or, the dealer didn't really investigate sufficiently.) If you have a multimeter, you can potentially use it as an ammeter, to look for current flow from the battery when the car is off. But that entails removing one of the battery terminals, and essentially inserting the meter into the path. But even if you do that, it is still tricky to try and figure out where the current is flowing. Usually you would removed fuses or relays one by one to note when the stray current went to zero (or almost zero). Again, you'd need to have the problem occurring, and not be too intermittent.

It's also conceivable that it is a failing or intermittent alternator, although I doubt that would be the case (since that would be easier to check).

You might also look for some interior lights that are left on. But usually if an interior light is left on, it would take more than an hour for the battery to be drained. (But, leaving an interior light on overnight could well lead to a drained battery.)