I guess I am also a victim of listening to the radio espn sports(go bears!) while cleaning my two cars in 45 degree weather.

after finishing both vehicles and it was time to park it inside the garage, the battery of the escalade just went dead

maybe too much sports radio but this should be normal stuff.

anyway, I also found out that I was charging my "smartphone" at the back's 112V outlet. all, contributing to this.

fortunately, I had a SEARS charger and rapid start equipment. the fast start would not work as it had only <9V. anyway, after 30 minutes of rapid 30A charging, it went up to 13.3 V charge and fired right away.

will the dealership replace it under warranty? any experience?

 

The reason the 12V battery is small is because the engine is started by the traction battery. you may notice there is no starter on your engine. The 12V system is basically for compatibility and control. There is also no conventional alternator. The 12v system is charged off of the 300v system.

 

You can check the cell of the battery with a meter. If you are capable of doing it.
Have a meter set to 12 vdc, open up the caps of the cell. Yes you can open on the maintenance free battery.
Place the black lead on the neg post, dip the red lead in to the cell, not touching the plates. The cell should read, 2 vdc in each. This adds up to the 12 vdc. If you get one that is low, it has a shorted cell on the plates. Again, just dip the lead into the acid.
When complete, make a solution of baking soda and water and dip the leads in to neutralize the acid. So it does not eat away at the leads.