any problems exist if constantly listen to radio when car is off?

It will run your 12v battery down if left on for long enough and may scare your neighbors if you sing to to the tunes on the radio.

 

I have sat and listened to the radio when the wife was grocery shopping, after maybe 30 minutes, not sure about the time, but the car shut off automatically and display had a message that said something like shutting down to conserve battery. I think it will pretty much take care of itself, seems to be pretty well thought out.

 

Ok, I have to go on the record here.

We have an 07 and an 11, and playing the radio did, in fact, leave us stranded recently in our 07 [maybe the firmware is different in the gen 3 -- I don't know].

We stopped for about 15 minutes to pick up something. My wife stayed in the car, and as we often did, she listened to the radio with the car in accessory mode one [or whatever it is called -- one button press]. Yes, the battery was four years old, but there was never a problem starting it, and infrequent checks of the 12v battery [mfd reported voltage, with and without lights on] seemed OK. Before I returned, the power shut down on it's own -- as it often had if I was late returning -- and she assumed it was a 'normal' auto shut-off.

However, when I did return, it simply wouldn't start. Not enough 12v to boot. I had to chase down a jump start.

Bottom line -- not that it is advertised otherwise -- just be aware that the auto shut-off is independent of the actual charge remaining in the 12v battery. Impending doom will not be foreshadowed by the familiar 'slow crank' like your previous non-hybrid ride.

From now on, if I leave anything on, I will leave it running. At least the gas tank has a level indicator...

 

Was that the original 12V in the 07? I gotta imagine after 5 years it's on it's last legs and has little capacity left, whatever the test results return!

 

...not sure you own a Prius, but some say the Optima replacement 12v batt is more forgiving of deep discharges from listening to radio too much.

 

You sure about that? If one follows http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html, there's a voltage drop when you got from ACC to IG-ON. In IG-ON, the instruments turn on along w/the HVAC fan and all. If one then goes to READY mode, the voltage goes way up, since that should trigger the DC-DC converter.

I'm not convinced that running in IG-ON is better than running in ACC. In fact, it seems IG-ON puts an even heavier load on the tiny 12 volt, as evidenced by the voltage drop.

Yeah, I'd leave it in READY mode.

One should be fine by leaving it in READY mode. The engine is off almost the entire time but the 12 volt bus (and 12 volt battery) seems to be getting power from the DC-DC converter (powered by the big HV battery) in READY mode. The engine will only turn on and run for a bit when the HV battery runs low, and then shuts back off. One's using a lot less gas than an non-hyrbid sitting w/the engine running the whole time.

We've seen many stories of people having left their cars accidentally on (in READY mode) overnight or even longer. Their mileage ends up being crap for that tank and their gas gauge might've gone down a notch.

 

Yes, but not the point. I was trying to make three issues clear to save someone else a long walk:

a) prior to being stranded, there was no indication that the battery was on its last legs -- it had never needed to be jumped or recharged, and the trivial tests mentioned elsewhere in this forum did not seem to indicate any issues.

b) at least in the 07, the auto-off mentioned elsewhere in this thread does not seem to behave like some other low battery cut-off implementations which claim to "leave enough to get going again".

c) it was [to the point of the original post], playing the radio alone that pushed it over the edge.

 

Yes. I would leave the car in READY mode if you want to run the radio or any accessories for a long period of time.

Yes, in READY mode, when stopped, the car is pretty quiet given that engine isn't running for most of it. You'd hear a soft electrical whine and if the AC is on, the compressor is pretty loud. No, it won't damage the battery at all if left on "too long". I doubt there'd be any damage if you left the car on with a full tank until the car ran out of gas.

The people who forget are those who didn't read the manual and didn't have a salesman that properly showed them the operation of the car. If you leave the car in READY, get out of the car and shut the door, the car will beep at you a few times. They've ignoring the bits and and then ignored the engine turning on periodically to keep the HV battery charged (or not been present when this happens)...

I don't recommend using ACC only for very long, unless you want a flat 12 volt and want to have to replace it after flattening it too many times.