Question-2025 Prius in EV Mode: Reply quickly!

Put it in EV mode and that’s it. It’ll still switch but only after the battery is run down.


iPhone ?

 

If it is in ev only mode the only way for the ice motor to turn on would be to run out of battery.

 

You probably exceeded the maximum BEV-mode speed, which is 84 mph (135 km/h) in both Gen 4 PHEV and Gen 5 PHEV.

■Gasoline engine operation in
EV mode or AUTO EV/HV mode
Even if there is a sufficient amount
of electricity remaining in the hybrid
battery (traction battery) and EV
driving range (P.155) is being displayed
on the meter, EV driving
(driving using only the electric
motor) may be canceled and both
gasoline engine and electric motor
are used depending on the situation
(EV driving will be returned to automatically
after EV driving becomes
possible again).
EV driving may be canceled automatically
in the following circumstances*1:
●When vehicle speed is more than
approximately 84 mph (135 km/h).
●When power is needed temporarily,
for example when the accelerator
pedal is depressed firmly or
when accelerating suddenly.*2
●When the temperature of the
hybrid system is high.
The vehicle has been left in the
sun, driven on a hill, driven at high
speeds, etc.
●When the temperature of the
hybrid system is low.
●When the heater is switched on
when the outside temperature is
below about 14°F (-10°C).
●When the windshield defogger
switch is pressed. (P.434)
●When the system determines that
the gasoline engine needs to be
started.
*1:The gasoline engine may also
operate in circumstances other
than those listed above, depending
on conditions.
*2:When driving in AUTO EV/HV
mode. Even in EV mode, the gasoline
engine may start, depending
on the condition of the hybrid
battery (traction battery).
■If “Engine Started to Clean System
EV driving unavailable” is
displayed on the multi-information
display
EV driving may be canceled in order
to protect the hybrid system, etc.
In this case, perform driving with the
gasoline engine until EV driving will
be returned to automatically.
Depending on the conditions, driving
that combines the use of the
gasoline engine may continue for a
short while. However, this is not a
malfunction.
■Conditions in which the gasoline
engine may not stop
The gasoline engine starts and
stops automatically. However, it
may not stop automatically in the
following conditions*:
●During gasoline engine warm-up
●During hybrid battery (traction battery)
charging
●When the temperature of the
hybrid battery (traction battery) is
high or low
●When the windshield defogger
switch is pressed. (P.434)
*: Depending on the circumstances,
the gasoline engine may also not
stop automatically in situations
other than those above.

 

There are speed limits to EV mode. Plus the system will turn on the engine if it feels a need to protect the battery no matter the mode.

 

In EV mode, the power request from maximum pedal travel is set at a level the battery should be able to supply in most conditions. The middle mark in the 'POWER' part of the hybrid system indicator.

Therefore in most conditions, putting your foot down will provide that maximum EV mode power without needing to start the engine.

But the maximum output from the battery is affected by temperature and charge level, so it is still possible for the engine to start if your heavy foot exceeds a restricted battery. It doesn't lower the available system power, it just gets the engine to help to ensure consistent driving behaviour.

Plus it can start for cabin heat.

So here the engine will routinely run below -10°C for the cabin, and between -10°C and 0°C the engine tends to start to help when range shows 11km.

The latter effect can be reduced by the battery heater function.

 

Another way of thinking about this is that if you didn't want to burn any fuel, you should not have bought a hybrid car.

The programming of this car takes advantage of the fact it has the engine available to avoid excessively stressing or inefficiently using the battery.

So it will give the battery a break when hot or cold. The EV would tend to push it harder.

So your wishes to preserve the battery life but never burn fuel are conflicting, and Toyota have prioritised the former.

The G5 is trying to give you more of an EV driving experience than the G4 did, but there's a limit to how much they want to give the battery an EV experience.

 

It is not supposed to do that unless you are in the EV-Auto mode. See the notes in the manual. Heavy acceleration starting the engine only applies to the EV-Auto mode. If it did, why in the world do they have the EV-Auto mode then?

 

One curious behavior is that if you switch to the HEV mode, you cannot switch back to the BEV mode until the engine warns up. This is to protect the engine.

 

EV only mode will not kick to HV mode just because of strong acceleration, if you had it in auto mode it would, but it sounds like it did what you wanted anyway, as EV only mode does not accelerate very fast at all, Toyota designed it that way to help preserve the small batteries life. If Toyota designed it to allow for strong acceleration like most full on EV's, then the small battery would discharge way too fast and they would probably be replacing a lot of batteries before the warranty was out. Auto or HV mode is where it's at if you want brisk acceleration to show off to a sports car, that's a strange sentence to type lol.

 

EV Auto mode will always start the engine if you floor it. Because max power in that mode is the end of the hybrid system power indicator, which is more than the battery can ever supply on its own.

EV mode usually won't, because the battery can usually supply the mid-'POWER' level it has as its maximum, but if the battery's not in its temperature/SoC comfort zone, it can start the engine to ease the battery. Usually won't, but it can. I don't know why it did in your case, but I'd guess high temperature contributed. Certainly you should expect the engine to normally stay off when you floor it in EV mode. (Below 80-odd mph)