READY -> ACC?

No, the order of events for the power button is (without brake depressed) ACC -> Ig-on -> (depress brake here) Ready -> Off.

The easiest thing is to just put the vehicle in park, as if you were done driving it, finish doing what you want and power off. Unlike a conventional vehicle this one should not be running the ICE while in park unless the engine has not completely warmed up, or your battery power is rather low and the computers decide to do some charging.

 

I've been wishing for the same thing on several of my posts, and for the same reason. Except instead of music, it's a talk program on the radio, and I want to continue listening while I get the mail.

 

Rather than ask the question again, I thought I'd revive this old thread.

This is honestly one of the most ridiculous things I've found in the Prius' user interface.

On any normal car with a key, you can shut the engine off and go directly to battery mode. On any normal car with a key, you can also turn the key from ACC directly to off.

Is there really no way to do this? I have to cut the radio off if I want to continue listening to it on 12 volts? And then again I have to abuse all the computers and relays by going to IG-ON before I can power off? Really?

And please don't tell me to sit in the car in READY mode... I sit sometimes for HOURS in the car and, although it was my dream before I bought the Prius to just let the car produce 12v and run the engine as necessary, I find that in reality too much stuff is powered up in READY mode and it uses a lot of HV battery and gasoline, relative to the meager amount necessary to power the radio and charge my phone.

Don't get me wrong. I do not want a normal key! Seriously, you'd have to pry the smart key out of my cold dead... well, let's just say it is SO convenient that my fingers never actually touch it. Truly one of the most awesome features of the car.

I just want to be able to directly go to the various modes, rather than having to cycle through them.

 

Nope, no way to do it.

 

Leave it READY. Get used to it. Otherwise you will one day drain the 12V battery, which is a pain, or you will drain the traction battery, which is an expensive pain.

 

Furthermore, you don't want to run a Prius radio for hours without being in Ready. The 12V battery is small, and will not survive this sort of abuse. In fact the Prius is programmed to automatically shut off the radio after one hour. You have to restart it if you want to listen longer.

Tom

 

I keep an eye on the voltage, so as not to abuse the lead-acid battery too much.

To my understanding, you can put the car in ACC mode as much as you like and never hurt the traction battery. However, if you leave the car in READY and leave it long enough, you will eventually run out of gas and kill the traction battery.

 

Yes, as I said I sometimes sit in my car for hours, I am well aware that it shuts off after an hour.

I have the version with SKS. The battery is not so small. It certainly survives the radio and cell phone. It helps to turn the MFD display off.

And if it does start to lose its capacity significantly, it'll just give me an excuse to get an Optima.

 

Correct, using ACC can kill only the 12V battery. IG-ON, or READY and in Neutral, can kill the traction battery.

A full tank is probably enough to power the radio for a week. Unless you're one of those nuts who tries to see how long they can go before buying gas you will not have a problem.

 

I know what you mean....it's just annoying sitting in a car and having the ICE start up several times to boost up the HV battery charge and then shut off...and the same cycle over & over again...

 

I'm not concerned with running out of gas and harming the traction battery. I am concerned that it is a big waste of wear and tear on all the systems and the ICE by having it all powered up just to listen to the radio.

So I've pretty much accepted the idea that the proper way to to it is to use the 12v battery. Now I just want a way to not have to go through IG-ON to power the radio on and off.

Perhaps I'll have to wire the radio up to be on all the time, or have a manual switch. But then I'll eventually forget and drain the 12v...

Hmm....

 

No, you aren't getting it. If you drain your 12V battery, it CAN harm the traction battery.

Think of the Hybrid Synergy Drive (HSD) as a symphony. It takes all the parts, working at least well, if not perfectly, to keep it all in tune (not to be mistaken with a tune-up, of course). If you drain one part of the HSD system by sitting in IG-ON listening to the radio, the stress is felt elsewhere in the system.

It is the 12V battery which powers up the computers, which starts the car. The computers pull from the traction battery for the necessary juice to do so. A weak 12V will skew the system, and could cause the computers to mess up those commands to the traction battery. You'll start seeing weird errors, etc.

Really, just run it in READY mode. Turn off the heat/AC, the headlights, and make sure you don't have a maplight or other electric device, other than the radio, going, and you'll find that the engine runs pretty rarely. This will protect the entire HSD system.

 

I second (third?) the idea of staying in ready. If you turn off the climate control and MFD display, the load on the traction battery is very slight.

If you do a short force charge before you go to park (car in D and foot on gas and brake at same time), then you can run the radio for a long time without the engine firing up. The traction battery was made to be cycled, whereas the 12v battery was not. By deep cycling it, on top of letting it sit once you have discharged it, you are guaranteed a much shorter life on it. Plus, this does indeed still cost you fuel even when using ACC, as the DC-DC will have to recharge the 12v when you next go ready, and this energy ultimately comes from the tank. (unless you have a PHEV)

For me, when I'm working on the car or around it, I leave my PHEV's plug connected and go to ready. I can even run the A/C and it all comes from the grid, so there is never an engine run.

 

Well, great master pEEf, if anyone is qualified to talk about the electrical load in READY vs ACC, it would certainly be you. I have measured nothing so far. My claim to fame is the voltmeter I leave stuck in the cigarette lighter.

I agree about all the battery use and longevity and chemistry etc. But I still don't know the actual load of all those computers and the inverter pump.

Also, what kills me is all that nice hot coolant going to waste instead of being pumped into the thermos. Are you sure that it doesn't take a lot of fuel just to keep the engine somewhat warm?

For that matter, has anyone actually measured the amount of fuel it takes on say, a 45 degree F day, to "keep the radio on"? I have a feeling it is MUCH more than it takes to recharge the Pb-A on the next drive.

All that being said, much of the time is sit in my car is at work between shifts, in a nice parking garage, which has around 20 stalls with outlets labeled "electric car plug-in". I wonder what that means?

Seriously, I want to plug my car in real bad. First step, instrumentation. Now let me go see if there's any update in that "priuscan" thread... I'm just THIS close to pulling the trigger on a CANview...

 

Add a 12v charger and then you can plug in while sitting in your car. Then no 12v battery discharge!

 

Funny you should mention that. I just tonight found the +12v connection under the hood and hooked up an electronic charger.

I'm not sure it would be worth the trouble to wire up a power cord and plug the car in just to keep a float while listening to the radio. Probably be more realistic to just get a bigger battery and wire up the cigarette lighter to stay on and plug it in at night in my garage using that. But I ultimately want to do PHEV, so I'll wire up the 12v at that time.

But even if I have unlimited 12v, I still want to go from READY to ACC, and from ACC to IG-OFF.

So, how?