Cold Start, Full Battery, But No Ev Available

[kevin h]

My Gen 3 now has 28K under its belt and has been through 3 winters with some engine noise issues which (Touch wood) have not re-occurred since the Engine Manifold Replacement.

However, during this very cold spell I started the car in the garage, noticed a nearly full Battery (1 bar from the top) and decided to go straight into EV.

To my surprise, the message came up to say that EV was unavailable.

Any ideas? As I'm used to being able to drive up to 20 mph on a cold day before the ICE kicks in normally. I'm thinking that it might have something to do with the Engine Manifold, but am not clever enough to know if that might be the case.

Must admit though, my MPG at 60mpg is still pretty good for this weather.

[sjrainsford]

On my Gen 2 you have to be pretty quick putting it into EV mode and if you miss it, it won't let you as it wants to go into the compulsory engine warm up cycle. If the car runs normal otherwise I wouldn't worry about it. There are so many factors that can effect that such as temperature etc.

[kithmo]

If you had the heater or front demister on it won't go into EV from cold, otherwise it should go in if you press EV within 12 seconds of pressing the start button. I'm not sure if the headlights on loading affects EV availabilty as well.

If none of the above then maybe a fault ?

[Grumpy Cabbie]

You don't really want to be manually selecting EV mode. Let the car warm up in 'Normal' mode as there are a number of different sequences it goes through in the first couple minutes in a cold start and over-riding them might not help your economy. Also, cold, subzero weather is not the best for any Battery, let alone your car HV Battery, so you can see how your Battery is protected from EV mode when it has been sat in a cold car outside in -7c etc.

EV mode has its uses but you're best leaving it alone to get the best mpg's and performance. Don't believe me, but there are some real clever engineers on the US Priuschat site who have measured this scientifically. Manually selecting EV mode will, in 99% of cases result in less mpg's than if you let the car decide what's best.

[r04drunner1]

IMHO using EV at starup in circumstances where the electric motor is perfectly capable of driving the car at low speed makes sense. The key principle is trying to get the ICE (Internal Combustion Engine) working at its most efficient. It's not very efficient at low speed cold startups, with the rev range way below the optimum.

I deliberately chose EV sometimes when starting because I know it's only a short journey to the main road. If I can delay ICE startup until I am on the main road, then at least when ICE starts up the car will then be burning petrol more efficiently (in the best rev range, getting forward motion plus charge plus heat).

At the low speed coming out of my driveway and driving out of the development where I live, the ICE would be running very inefficiently because it's cold and not much power would be needed to drive the car thus the engine would not be working in its most efficient power band.

From what I have experienced, EV is unavailable from a cold start on my Gen3 if:

- the ICE has already started, or

- the climate control is on (not sure about this one, sometimes I can get EV with climate control on - I just don't get any warmth!), or

- the front demist is on, or

- the Battery is low

There may also be situations where the ambient temperature is so low the car decides it has to start the ICE to get up to operating temperature.

The clever Japanese engineers probably have other criteria as well for deciding not to make EV available.

So I would not be worried about "EV Mode is Unavailable" when starting from cold. To maximise the chance of getting EV I would advise you to:

1. Press EV as soon as possible once the car comes to READY, so you do not give ICE time to fire up

2. Do NOT switch on the front demister (unless you need it for safety reasons!)

3. Set the climate control OFF

If the Battery is at four bars or above, that's generally enough to let EV start. At three bars, it sometimes works but sometimes doesn't and I guess that is a function of ambient temperature.

HTH

R04drunner1 (p.s. Other more informed people here may be able to give you more detail)

[Grumpy Cabbie]

duplicate post

[Grumpy Cabbie]

The following might clarify why the Prius does certain things at cold start. It is a breakdown of the warm up stages written by one of the Prius designers in Japan. It applies to the gen3 Prius. You will notice that in some early stages (S1a) the car actually runs on the electric with the engine working as a generator (similar to the Chevvy Volt or a diesel electric train). The car is almost selecting EV mode itself to gain the best emissions and fuel economy and overriding this by using 'EV mode' is counter productive. (sorry for the long post but it might answer a lot of questions);

The Stages:

S0:

• it is from power on until the ICE starting for warming up (approx 12 seconds)
  
• you can enable the EV-Drive Mode during this S0, if the conditions are allowed so (refer to your owner's manual)
  
• the EV-Drive Mode can not be turn on when (1)the temperature of the hybrid system is high (ie; the hybrid Battery is above 46C), (2)the temperature of the hybrid system is low (ie; the hybrid Battery is below 0C), (3)the hybrid Battery charge level is low (three bars or less), (4)the windshield defogger is in use or (5)the engine coolant temperature is below 0C (maybe 20C on the US Prius)
  

S1a:

• when the start coolant temperature is below 40C, the warming up starts and continues for approx 50 seconds after S0.
  
• you can not enable the EV-Drive Mode during this S1a.
  
• the ignition timing is very late, after the top dead center. therefore the engine does not have enough power to drive Prius or charge battery.
  
• basically, Prius can not use the engine power when you drive. Prius is driven by battery power and the battery is discharged.
  
• it is good idea to drive slowly or stand still warming up in this stage.
  

• when the start coolant temperature is between 41C and 60C, Prius is in this stage, but the engine does not start automatically.
  
• when you press the accelerator (including driving), the engine starts and runs for approx 50 seconds or until the coolant temperature reaches 65C. the ignition timing is very late too.
  

S1b:

• this is an extended warming up stage.
  
• you also can not enable the EV-Drive Mode during thisS1b on Gen3. (you can enable the EV-Drive Mode on Gen2)
  
• the ignition timing is now normal, and the engine is able to provide power and charge battery.
  
• you are now ready to drive without any penalty of battery discharging.
  
• ( A ) if the the coolant temperature is still below 40C after S1a, the warming up continues until 40C.
  
• ( B ) if the the coolant temperature is between 40C and 50C after S1a, the warming up continues until 50C.
  
• ( C ) if the the coolant temperature is between 50C and 60C after S1a, the warming up continues until 65C.
  

S2:

• after the S1a or S1b, Prius goes to this stage.
  
• Prius acts as normal until the coolant temperature becomes 70C (going to S3).
  
• The EV mode speed is limited below 10 mph on the NA Prius.
  

S3:

• when coolant temperature becomes above 70C, Prius goes to this stage.
  
• Prius acts as normal, but Prius requires an "idling check ceremony".
  
• The EV mode speed is now allowed up to 25 mph on the NA Prius.
  
• the "idling check ceremony" is done during an accelerator off gliding for several seconds on Gen3. (on Gen2, Prius needs a complete stop or very slow walking speed for the ceremony)
  
• the engine continues to run during the several seconds ceremony.
  
• after the ceremony, Prius goes to the S4.
  

S4:

• Prius now completed the warming up stages and in a full normal condition.
  
• if the coolant temperature is above 60C on power up, Prius is already in this stage.
  

http://priuschat.com/forums/gen-iii-2010-prius-technical-discussion/76501-gen3-warming-up-stages.html

[ashpole]

My Gen 3 now has 28K under its belt and has been through 3 winters with some engine noise issues which (Touch wood) have not re-occurred since the Engine Manifold Replacement. However, during this very cold spell I started the car in the garage, noticed a nearly full battery (1 bar from the top) and decided to go straight into EV. To my surprise, the message came up to say that EV was unavailable. Any ideas? As I'm used to being able to drive up to 20 mph on a cold day before the ICE kicks in normally. I'm thinking that it might have something to do with the Engine Manifold, but am not clever enough to know if that might be the case. Must admit though, my MPG at 60mpg is still pretty good for this weather.

I usually move my Auris HSD out of the garage in EV mode before loading up my coat etc; then drive off in ECO Mode non-EV. Two mornings over the last week it has refused to go into EV Mode - the message read "EV Mode unavailable, too cold".

I think it really is human!

[smuddell]

This topic has been really useful relating to my new Auris HSD!!!

When I leave work, I drive out of the car park, then onto the main road, up a steady slope to go over a railway bridge. Usually there seems a lack of power going up this slope, and I now realise it must be in the S1a warm-up phase so there's nothing wrong! Hopefully!!!

[daveybee]

"EV Mode unavailable, too cold"... I know how it feels! It needs to wear a little hat (just like me)... Tee Hee.

[kevin h]

Well, all very useful information that I already knew.

Nothing is turned on and the EV button is pushed immediatly.

As I will try again tomorrow morning because yet again I have a pretty high SOC at the mement and the car is asleep in the garage.

I was just wondering why it should start to happen now.

:-(

[Jan&tone]

IMHO using EV at starup in circumstances where the electric motor is perfectly capable of driving the car at low speed makes sense. The key principle is trying to get the ICE (Internal Combustion Engine) working at its most efficient. It's not very efficient at low speed cold startups, with the rev range way below the optimum.

I deliberately chose EV sometimes when starting because I know it's only a short journey to the main road. If I can delay ICE startup until I am on the main road, then at least when ICE starts up the car will then be burning petrol more efficiently (in the best rev range, getting forward motion plus charge plus heat).

At the low speed coming out of my driveway and driving out of the development where I live, the ICE would be running very inefficiently because it's cold and not much power would be needed to drive the car thus the engine would not be working in its most efficient power band.

From what I have experienced, EV is unavailable from a cold start on my Gen3 if:

- the ICE has already started, or

- the climate control is on (not sure about this one, sometimes I can get EV with climate control on - I just don't get any warmth!), or

- the front demist is on, or

- the battery is low

There may also be situations where the ambient temperature is so low the car decides it has to start the ICE to get up to operating temperature.

The clever Japanese engineers probably have other criteria as well for deciding not to make EV available.

So I would not be worried about "EV Mode is Unavailable" when starting from cold. To maximise the chance of getting EV I would advise you to:

1. Press EV as soon as possible once the car comes to READY, so you do not give ICE time to fire up

2. Do NOT switch on the front demister (unless you need it for safety reasons!)

3. Set the climate control OFF

If the battery is at four bars or above, that's generally enough to let EV start. At three bars, it sometimes works but sometimes doesn't and I guess that is a function of ambient temperature.

HTH

R04drunner1 (p.s. Other more informed people here may be able to give you more detail)

100 percent agree. I always use EV to get the car out of the garage - why burn petrol while you are shutting the garage door when you don't have to! I also only have 200 yards to go before i hit the main road !

I actually had the same as the OP yesterday for the first time, the Prius hasn't been used since a trip back from the IoW 10 days ago and I got the 'EV not available, Warming up' message. Even then, the ICE didn't start until the car was actually out of the garage and I was already shutting the garage door...

Unless it happens on a regular basis I'm not gonna worry about it!

[Grumpy Cabbie]

This topic has been really useful relating to my new Auris HSD!!!

When I leave work, I drive out of the car park, then onto the main road, up a steady slope to go over a railway bridge. Usually there seems a lack of power going up this slope, and I now realise it must be in the S1a warm-up phase so there's nothing wrong! Hopefully!!!

Exactly that. Once you see how the Prius/Auris hsd system works through the various warm up stages it makes much more sense as to why the car does what appears to be weird things.

(the Prius gen3 & Auris hsd hybrid systems are virtually identical if not actually the same)

[kithmo]

Well, all very useful information that I already knew.

Nothing is turned on and the EV button is pushed immediatly.

As I will try again tomorrow morning because yet again I have a pretty high SOC at the mement and the car is asleep in the garage.

I was just wondering why it should start to happen now.

:-(

Did you miss the reference to the EV mode not operating if the HV Battery is below 0 deg C in GC's post ?

[Grumpy Cabbie]

Did you miss the reference to the EV mode not operating if the HV battery is below 0 deg C in GC's post ?

lol and I was trying to help them

This was the relevant section in bold;

S0:

• it is from power on until the ICE starting for warming up (approx 12 seconds)
  
• you can enable the EV-Drive Mode during this S0, if the conditions are allowed so (refer to your owner's manual)
  
• the EV-Drive Mode can not be turn on when (1)the temperature of the hybrid system is high (ie; the hybrid Battery is above 46C), (2)the temperature of the hybrid system is low (ie; the hybrid Battery is below 0C), (3)the hybrid Battery charge level is low (three bars or less), (4)the windshield defogger is in use or (5 the engine coolant temperature is below 0C (maybe 20C on the US Prius)
  

So during a "very cold spell" one or more of the above may apply and the vehicle will NOT allow you to enter EV mode.

Simples :)

[r04drunner1]

Did you miss the reference to the EV mode not operating if the HV battery is below 0 deg C in GC's post ?

lol and I was trying to help them

Yep and I got it. Thank you for the detailed post, it was interesting. It explained why my car suddenly gets a surge of power 200 metres after moving onto the main road, basically it then reaches stage S1b.

On balance, I still think my short burst of EV to get the car out of the drive and moving along the short road in our development is saving me petrol. And yes, for the reasons you stated, EV sometimes might not work. I knew those clever Japanese engineers had good reason for it.