I'm unclear on how gasoline consumption works when you are in EV mode.

The engine has to run for a variety of reasons, even in EV mode. It has to warm up the system and provide cooling to some of the electrical components. Also, if you are using the heater, it has to run to create the heat. Don't worry; the Prius is doing it's best to use your EV charge wisely.

 

Depending on how hard you accelerate, the ICE may come on. To keep it in pure EV requires a very light foot on the pedal. Also, as Greg mentioned, your cabin temp settings may cause the ICE to run. With the temp set to "LO" and "AUTO" off and the fan also off, you should be able to stay in EV mode. I regularly drive up to 14 or so miles around town without the ICE coming on. Also, once you hit 62 mph on the highway you can expect the ICE to start under a load. You might try "ECO" mode if you haven't done so already. It requires a little more push on the pedal, sort of a reminder to go easy on accelerating. I can use it and still cruise with traffic but taking just a tad longer to reach that speed. Finally, remember the car always starts in EV mode if there is sufficient charge stored. So don't press the EV button unless you intend to save the charge for later use.

 

EV forces battery-only whenever possible. Button off just acts as regular hybrid.

 

Like I said, it starts in EV mode by default when charged. Pressing the button will take it out of EV mode and the green indicator will go out. You are then in HV mode, in which the computer will decide when to run the ICE . You still benefit from the hybrid system in saving gas, but you won't run continuously in EV. You can switch the display to the "Energy Monitor" screen and see where the power to the wheels is coming from as you drive in either mode. The "Hybrid System Indicator" screen will show you at what point accelerating causes the ICE to come on.

On the opening page of the PiP forum, check out Lensovet's "one and only Plugin Prius FAQs" for all kinds of helpful info. The first section explains what I think is at the base of your confusion. Good luck with your PiP, which I gather is a recent acquisition? Although you have been a member here since 2012, the question has just come up?

 

The vehicle runs on EV when you are traveling at low speeds, even in HV mode. The engine can also shut off when you are coasting or decelerating, as it serves no purpose to run.

 

once you learn how to use it, you'll be able to drive all ev all the time like i do. if that's your desire.

 

Barbara is correct. The EV and HV battery are the same. EV mode will let you accelerate much more quickly than HV and allows you to use EV until ~62mph (depending on conditions it is from 62-65 or so).


If you are driving and switch over to HV it will consume EV power until the engine warms up. This is used to keep some of the strain off a cold engine. If you are over ~62 mph and have it in EV, you will use a combination of engine and battery, people on the board call this "EV Boost mode". You will see over 100 mpg shown while going highway speeds.

The PIP needs the engine to be warm for cabin heat. It seems the engine will start even without heat if the temp is below ~32F (depending on conditions and load this temp can change). Seems the PIP is anticipating that you will need the engine and wants it to be warm before you really need it.

If you use only EV all the time the engine will still start every ~120 miles to make sure there is fresh fuel in the lines etc.

Any time the engine starts it will not turn off until it goes through a full warm up cycle. (unless you turn the car off)