2021 Corolla 1.8 Hybrid change in battery/ECU behaviour

[KALA_]

Hi!

sorry in advance if this issue has already been discussed and most likelly is since this seems to be such an active community!

So i got this car 5weeks or so and it sits around 53k miles. My question is related to how and when the car switched between EV and petrol mode and how it has changes few days back.

First 5 weeks owning the car the switch between EV and petrol was more or less like i have been reading on variois forums. Battery sits around 3-5 bars out of max 8 and lifting from gas ar lower speeds EV activates etc

 

What i have noticed now is that the car does not go to EV mode at the same Battery levels as it used to. Before it maintained around 3-5 bars out of 8 and now it really wants to go to 6-7, even in red lights the engine turns on at 5 bars and loads it up to 6-7  

Also one completelly new thing i noticed is that car would drive on EV (according to dashboard arrow goes from Battery to wheels) but engine still maintains. 1.5k RPM for a while Any ideas or guesses why this sudden change in behaviour?

PS:

- engine was warm

- outside temp 13celsius

- half a tank of fuel

- AC on and AUTO mode with target temp of 21celsius

- no warning lights in dashboard

 

Thanks in advance.

[Mojo1010]

21C that is the mostly likely answer.

[KALA_]

You mean the difference in outside 13c and my target 21c?

I will be interested to see what the winter brings me when outside temp drops as low as -25c 😂😂

[trashman1965]

Turn off the HVAC or lower the temperature setting and see how it behaves. On dry cool mornings we're currently getting, I leave it off. Before I put the car into the garage, I turn it off. Minimises the time/fuel used to warm the cabin and I'm still currently able to reverse the car out when cold, shut the garage and drive first 75 yards or so in EV (further if no traffic and I keep below 20mph).

 

All things you learn as you get used to Toyota hybrid. Or just drive it and ignore dials/readouts/gauges 🤣

[AndrueC]

Most likely change in ambient temperature. Colder weather makes machines work harder. It can also impact the ability of the traction Battery to take charge or output energy.

It's typical to see a significant increase in fuel consumption over winter - more of an increase than a conventional car. It won't offset all the benefits of the hybrid system but it's very noticeable.

My 1.8 goes from mid 60mpg in the summer to mid 50mpg in the winter. Things I specifically notice:

• When backing the car out of the garage the ICE starts within 30 seconds instead of staying off until I call for power.
• I struggle to get through a local village entirely on electric power when coming through home due to the incline.
• A half mile long section of road that I can just about manage to drive at 50mph on electric power becomes impossible without using the ICE or letting the speed drop as low as 40mph (and other motorists will not like you doing that).

But it's just the way it is. I'm still using less fuel than most of the cars around me but the difference is not as large as it is in summer.

[KALA_]

1 minute ago, AndrueC said:

Most likely change in ambient temperature. Colder weather makes machines work harder. It can also impact the ability of the traction battery to take charge or output energy.

It's typical to see a significant increase in fuel consumption over winter - more of an increase than a conventional car. It won't offset the benefits of the hybrid system but it's very noticeable.

My 1.8 goes from mid 60s in the summer to mid 50s in the winter. Things I specifically notice:

• When backing the car out of the garage the ICE starts within 30 seconds instead of staying off until I call for power.
• I struggle to get through a local village entirely on electric power when coming through home due to the incline.
• A half mile long section of road that I can just about manage to drive at 50mph on electric power becomes impossible without using the ICE or letting the speed drop as low as 40mph (and other motorists will not like you doing that.

But it's just the way it is. I'm still using less fuel than most of the cars around me but the difference is not as large.

Thanks for the answer. My main question/concern is because of th sudden change how it behaves. If it works as intende im all good :)

[AndrueC]

Just now, KALA_ said:

Thanks for the answer. My main question/concern is because of th sudden change how it behaves. If it works as intende im all good 🙂

I don't typically see a sudden and dramatic change in performance but some of the things listed above feel sudden. The ICE always coming on is triggered, I think, by the garage ambient temperature being below 16c. So one day it'll let me drive to the end of my road on electric, the next day the ICE starts before I'm half way out of the garage.

[TonyHSD]

50 minutes ago, KALA_ said:

Thanks for the answer. My main question/concern is because of th sudden change how it behaves. If it works as intende im all good 🙂

The hybrids run engine not just to maintain cabin heat or engine temperature but also to maintain hybrid Battery state of charge, deviation between the different cells, and 12v Battery recharging. 
The change of the car behaviour might be as a result of these above and it will sort itself out with the time. 
How much do you drive and how often ? 
 

[KALA_]

1 hour ago, TonyHSD said:

The hybrids run engine not just to maintain cabin heat or engine temperature but also to maintain hybrid battery state of charge, deviation between the different cells, and 12v battery recharging. 
The change of the car behaviour might be as a result of these above and it will sort itself out with the time. 
How much do you drive and how often ? 
 

I drive every other day approx. Usually shorter in city distances 10-15km

Should i get into habit of taking ”scenic” routes just to get more distance in?

 

[KALA_]

1 hour ago, TonyHSD said:

The hybrids run engine not just to maintain cabin heat or engine temperature but also to maintain hybrid battery state of charge, deviation between the different cells, and 12v battery recharging. 
The change of the car behaviour might be as a result of these above and it will sort itself out with the time. 
How much do you drive and how often ? 
 

Forgot to ask. If the ICE would run due lets say AC or engine temp why would it still charge Battery that is already 5 or 6 bars out of 8?

[trashman1965]

12 hours ago, KALA_ said:

Forgot to ask. If the ICE would run due lets say AC or engine temp why would it still charge battery that is already 5 or 6 bars out of 8?

It will charge the HV Battery anytime there is "surplus" energy from the engine and capacity in the Battery. Up to a point at least...it does like to maintain around the halfway mark. But over the time I have had 3 different Toyota hybrids I have noticed the charging behaviour does change. My guess it's trying maintain and keep the Battery conditioned.

Also note that the charge rate when the engine is running is not as great as you might think and more comes from regen braking so it's not like it's wasting fuel to charge or over charge the battery.

[fred88]

Interesting, didn't know that about regen vs ICE charging.

[KALA_]

23 minutes ago, trashman1965 said:

It will charge the HV battery anytime there is "surplus" energy from the engine and capacity in the battery. Up to a point at least...it does like to maintain around the halfway mark. But over the time I have had 3 different Toyota hybrids I have noticed the charging behaviour does change. My guess it's trying maintain and keep the battery conditioned.

Also note that the charge rate when the engine is running is not as great as you might think and more comes from regen braking so it's not like it's wasting fuel to charge or over charge the battery.

Do you mean charging behaviour changes permanently as the car and the Battery pack gets older and more miles or do you mean the charging behaviour changes back and forth from time to time?

[AndrueC]

I think it's constantly 'doing what it thinks is best' and this is affected by driving behaviour, ambient temperature and quite possibly the phases of the moon 😁

It's fun to wonder about these things but not worth worrying. It's a clever system and I'm sure it has good reasons for these things 🙂

[KALA_]

1 minute ago, AndrueC said:

I think it's constantly 'doing what it thinks is best' and this is affected by driving behaviour, ambient temperature and quite possibly the phases of the moon 😁

It's fun to wonder about these things but not worth worrying. It's a clever system and I'm sure it has good reasons for these things 🙂

Yeah true it is! 😄 Bit paranoid ofc about the next and my first hybrid health check and therefore the continuity of my 10 year Battery warranty 😂

[Cyker]

It's pretty normal - I think it's one flaw in the design of the hybrids, a side effect of the very lightweight engines. They don't hold heat, so if you have 20+ cabin temp set and it's cold outside, the HVAC sucks all the heat out of the engine very quickly so the engine has to run more often.

To avoid wasting energy, it will dump as much of that into the traction Battery, but if the traction Battery is near-full it will just run the engine and waste fuel as it would in a normal car.

 

[Red_Corolla]

14 minutes ago, Cyker said:

It's pretty normal - I think it's one flaw in the design of the hybrids, a side effect of the very lightweight engines. They don't hold heat, so if you have 20+ cabin temp set and it's cold outside, the HVAC sucks all the heat out of the engine very quickly so the engine has to run more often.

To avoid wasting energy, it will dump as much of that into the traction battery, but if the traction battery is near-full it will just run the engine and waste fuel as it would in a normal car.

 

This is exactly why I start turning my heater OFF at this time of year when I'm only doing a short hop, as long as I can get away without the demisting. This, combined with keeping the 12v Battery topped up, makes a big difference to the amount of engine-on time.

[Cyker]

Yeah, I feel they could have done with a heat pump or electric heater for more efficient heat generation, as I have to choose between being warm and loosing 20mpg or keeping 70+ mpg but being a snowman when it gets very cold!   

 

[TonyHSD]

14 hours ago, KALA_ said:

I drive every other day approx. Usually shorter in city distances 10-15km

Should i get into habit of taking ”scenic” routes just to get more distance in?

 

Thanks, this explains everything. 
No need to take the car on a long journeys if you don’t need to. With the time the car will go back to normal. 
Engine charges and discharges the hybrid Battery to as mentioned condition it, minimise the cells deviation so most of them are at similar voltages. The hybrid system will do that as many times as necessary until Battery cells been equalised and the higher state Battery charge 7-8 bars will be as a result of that condition. When the car is used on longer journeys like 40-60 min and more and the hybrid battery been charged and discharged many times and the hybrid system is happy the car will behave normally again.