charging electronics after shutting off engine

If you're going to leave stuff plugged in (or use the electronics) I would just leave the car on. The engine won't run while it's stopped anyway, until the battery gets low enough that it needs to be charged.

 

you should be able to put it into accessory mode. power it off, then power on without foot on brake.

 

To answer your question things are the same. When the car is off, what we call "not READY" in Prius land (because the car can be READY with the engine off or on), the hybrid traction battery is physically 100% removed from the car's circuitry through relays. This is for safety and to prevent depleting the traction battery when the auxiliary battery would otherwise die.

Also in a standard vehicle with an engine and a starter, the battery needs to be big. When you turn the car on, it draws many many amps for seconds to spin the motor up before the engine starts firing properly and keeps spinning. Therefore the battery is big. In the Prius, it does nothing but flip some relays to re-connect the traction battery to the vehicle. It does some other things like keep your radio presets and prime the brake pump, but that's it. The battery is very small. Once the traction battery is online that is what used to spin the MG (MotorGenerator, fancy word for one of the two electric motors under the hood) that then starts the ICE (engine).

So in a Prius, you have less time available to listen with the car not READY. But if you keep the car READY, it will automatically keep things charged and only start the engine when needed to top off. So that is the method that should be used. There is a 500W or so draw to power everything with the car READY including the radio.

 

accessory mode uses less power and unless you plan to make it an all day affair you should be fine. I was in Seattle on Thursday charging my LEAF at the Discovery Center Quick Charge station and next to me was a lady sitting in her ICE. She had pulled in same time as me and dropped off someone I would guess to be her son. After 25 minutes, I had all the charge I needed. she was still sitting there idling away...

 

Absolutely. I do this on a regular basis so that I keep the SOC from dropping on the HV battery. I don't think it is stressing anything to charge a cell phone or listen to the radio off of the 12V battery, unless you plan on doing it for 30 minutes.

Unbelieveable! Of course, there are way too may people who don't understand they can listen to the radio in their cars without having to turn on the gas engine!