not understanding accessory mode yet

Some things in life, my reaction is: uhuh, uhuh, ok, I'm never going to use that, or it's going to be detremental, so I won't spend any further time investigating/learning it.

Accessory mode on the Prius is one of those things. Leaving the car in accessory mode, listening to the radio, charging the phone, soon enough you'll run the (diminutive 12 volt down). My take: don't start the car till you're going somewhere, start it "fully", and when you get where you're going, shut it down immediately. Fugedabout hanging out in the car.

 

welcome!
air conditioning, or fan?

you've messed around with it so much, maybe you're leaving it on and don't realize it.
get in the habit of powering down and locking the doors when you get out.

as far as charging your phone is concerned, some here have tapped a live 12v wire to make their own port for charging, but beware, the 12v battery is very small, and easily drained. i don't know how much juice a cell phone requires, but i would prefer to find another way to charge my phone.

 

Accessory mode and ign on mode are for very short term use only. They will drain the 12V battery very quickly and leave you stranded. Use them to:
roll up windows you forgot to close when you shut the car off, to avoid going back into "ready".
listen to a very short bit of radio, perhaps the news, although putting the car in "ready" is better.
testing an accessory without having the car start the engine in "ready".

They are there mostly for legal requirements. Like "N", DON'T USE THEM LONGER THAN A FEW MINUTES!

If you really want to drain the Prius 12V battery you can wire a circuit to the battery (with a suitable fuse) to charge your electronics so it's "always on". Some have modified the cig. lighter socket this way. -I- wouldn't advise it. Take your electronics with you along with a 115V charger and use it where you go. Outlets for charging are appearing everywhere.

 

Your first "issue" is easy. American cars keep that circuit live (generally) and everything else kills that circuit when the car dies (generally). This is something that annoys me to no end when I am forced to rent a domestic Big-3 car. When I press off, I want the radio off and all the electronic ports to power down. In american cars, the radio keeps playing until I open the door and the ports may or may not stay live forever. I don't want to unplug my radar detector everytime I turn the car off!

So that's what you are discovering coming from a Dodge vehicle. It is designed that way on purpose. Leaving a car in accessory mode is also a terrible idea. As you learned, you then cannot lock your vehicle and you are powering the entire system (HVAC fans, nav screens, lights, etc) from the 12v battery. If you haven't looked at the 12v yet, it is like a golf-cart battery because it is not meant to start and crank an engine. It flips some relays and goes back to sleep. Running in ACC mode for almost any non-zero length of time will kill your battery. Don't do it. This also counts if you are one of those people that sits in their car for an hour or two outside of a store waiting for someone else to shop, or if you eat lunch in the car, etc. The Japanese don't do that, it is not designed to do that.

If you want to make the port live when the car is off, you will have to run a live wire and hack into the back of the socket. It is not a bug or problem with your car, that's the way it is designed.

As to the AC running, if you are leaving it in ACC mode, then the fan will be running (and draining the 12v battery). If you are leaving it in READY, then the AC and fan may be running but they will run off of the inverter which will inturn run off the engine when the main HV battery gets low. Otherwise, you are most likely forgetting to turn the car off. The engine may be off, but the car isn't when you get out. And if you're used to american cars where the radio keeps playing until you get out, that may be perfectly normal to you to get out with the radio still going and not signal that the car is still on.

A little trick is just to lock it when you get out. After you get out, press the SKS button on the door and have it lock the car. If any of the doors are open, it won't lock. If the car is anything but off, it won't lock. In the first case the dome light can kill the 12v by leaving the light on. In the second depending on the state it could kill the 12v or just run all night long in your garage.

 

Its one of those give and take things when you hop into a prius, the 12v battery won't be that versatile compared to traditional non-hybrid vehicle. How the hatch doesn't open when engine is on is one of the biggest thing that I had to adjust and live with.