Question on EV/EV Auto buttons

Congrats, Kevin. Others here can answer your questions. Enjoy the ride.

 

Congrats.

The EV button has a few settings and yes you can run in HV mode with the battery fully charged, although you will lose a little EV range due to the HV mode using the EV battery when doing its thing. There is really just one battery pool, and it just goes down from the top (at least my understanding). There are essentially three modes I am aware of EV, EV Auto and HV mode. There is technically a 4th mode that most people will tell you not to use which is Charge Mode which will charge up the EV battery while driving. There are times this may be appropriate in certain conditions but in general probably isn't.

If you push the EV button you will see it cycle through modes on the display. You can also push the HV/EV button to flip between HV and EV mode. There is a functional guide that covers what the buttons will do in the manual. Depending on current mode the button has different results.

In EV Auto mode the car tries to make intelligent decisions on when to run in EV and when to flip over to HV mode. In EV mode you are instructing the car you want to run in EV mode even if the car would otherwise pick HV. In HV mode you are saying run the gas when I am driving above a fairly low speed. This is like operating a normal Prius, although it may not try as hard.

The two buttons are a little different. The HV/EV button can not activate EV Auto.

 

Hi Kevin,

Yes, the HV/EV Button will switch between EV only mode or Hybrid. The car turns on EV mode by default when starting up. You can manually switch to EV Auto, I think Gas Engine kicks in around 84MPH on the freeway or something under EV Auto. In EV mode, the Gas engine kicks in faster and earlier than EV Auto.

If you hold the HV/EV button, it will switch to the Charge mode. Press and hold again to exit that Charge Mode.

Drive Mode is completely different from EV/HV/Auto. It has to do with how much power you want while driving. I noticed the ECO mode really slows down the car, in terms of acceleration.

 

We have played with modes a little. I am not certain why we need so many modes.

It seems to us that in EV when outside temps are -F it takes a really long time for the cabin to warm up and for the defrost to begin clearing the windshield. So we have been running the ICE to help generate warmth.

We have also played with the CHG mode, it does bring up the battery charge fairly quickly.

 

Posted via the PriusChat mobile app.

 

Eco mode setting is kind of worthless because there is a separate eco button for the a/c system, so all it does is remap the throttle. Never used power mode on my liftback either.

 

It's still very handy for those of us in the north who will be using the engine for heat at times.

The ability for ECO to lower the coolant threshold reduces gas consumption.

 

What does that mean, and how is it different than air conditioning eco mode?

 

a separate eco button for a/c, or hvac?

 

Owners manual Page 490.

Air conditioning eco mode
The air conditioning system is controlled with low fuel consumption prioritized such as reducing fan speed, etc.
Press [Eco Heat/Cool]
The air conditioning eco mode switches between on and off each time is pressed.
“ECO” is displayed on the air conditioning screen when the air conditioning eco mode is on.

Toyota calls the entire HVAC system the, "Automatic air conditioning system".

 

exactly.

 

With gen-3 came ECO mode, which would lower the "engine on" threshold from 145°F to 114°F for the coolant temperature. That enabled the heater to run longer when the engine was off, since that trigger could be adjusted by the driver. It resulted in less gas being consumed.

With PHV came a tiered approach, dropping thresholds even lower depending on heater settings and battery-pack temperature. (I've seen it down to 82°F). That resulted in an even greater return from ECO mode.

You need an aftermarket gauge to see the sophistication of the system. Toyota does not provide that level of detail in the owner's manual.

 

you're saying eco mode will still do this, even though there is now a separate hvac eco button?

 

I would suspect we get 2 settings because there are now 2 heaters (gas & electric). Having control over both would be nice.

 

good point. maybe the new eco button suppresses the heat pump and the old button the engine temp threshold.

 

In EV Auto mode, under what circumstances do you see it switching over to HV operation? I'm hoping that it's something along the lines of EV mode except when:

• Out of battery,
• >55MPH,
• Very-high acceleration, or maybe
• Climbing reeeally steep hills.

Is it roughly along those lines?