2014 PIP Battery Drained, Although Charged Overnight

you didn't leave the car on. if you had, there wouldn't be any problem unless you ran out of gas. you left something on, or the door ajar and drained the 12 volt. not while being charged, but after charging finished. it's small, and drains quickly.

try plugging it in, and see if that charges the battery enough to start it. if not, you'll need a trickle charger, and then regular testing to make sure it isn't damaged. either way, it should be under warranty.

 

the hybrid drive battery is the one your charging. the 12v gets charged at the same time if it needs it, and also while your driving. the hybrid drive battery is not connected to anything until you make the car ready, which requires a healthy 12 volt. if, for instance, a door is ajar, you'll be fine until the hybrid battery is finished charging. then the 12 volt no longer is getting a charge, and believe it or not, the dome light can drain it fairly quickly. then, when you get in and press the power button, nada.

 

Seat heaters are only active in 'on' mode (all electrical accessories active but hybrid (traction) battery disconnected) and of course in 'ready' mode, they are inactive in accessory mode or when off.
If you are sure you shut off the car than it's not the seat heater that caused it.

 

Having a door ajar overnight can run the 12 volt battery down to near drained. Maybe it's more than one light: the (two) map lights, and the "dome" light. At least on ours, a door ajar will also turn on: the foot well lamps, the door sill lights, and the door courtesy lights. It's an effing Christmas tree, lol.

 

I had a sun visor flipped down with the little door open so that the sun visor/vanity light is turned on. I didnt notice it was on during the day time, but that vanity light will turn on even if the car is off (as long as the little door is slid open). That light, itself, drained my 12V battery (and this was when my car was only about 2 years old).