Using Leaf USB & Aux for charging phone, etc.

Looking ahead, doing a little prep. It sure would be nice to be able to use my
2014 Leaf's big Lithium battery to charge small electronics during a power outage.

Looks like the USB port and the 12v Aux port aren't active when the car is off.
When the car is on, they both work fine for charging, but here's my question.
When charging my phone this way, which battery is being used?
The main lithium ion battery or the smaller 12v car battery?

Anything 12V is the lead acid battery. The lead acid battery is in turn charged by a DC-DC converter. If you run things off of the 12V system in "radio" only mode, the 12V lead acid battery will discharged until it goes flat.

In run mode, you can run 12V loads almost indefinitely. You can also use a 1000W inverter to produce 120V AC, although I would recommend you spend a little extra and buy one that produces pure sine wave AC.

Lots of existing threads on these forums RE using an inverter.

As the search engine here sucks, use Google instead:

https://www.google.com/search?q=inverter+site%3Amynissanleaf.com&sxsrf=ALeKk01WmGyx0TPncWYABSFwIi-axoohjQ%3A1624828878513&source=hp&ei=zuvYYN_qHMXOtQa2h7W4CA&oq=inverter+site%3Amynissanleaf.com