Strange battery behavior

[OXYGEN]

Today was not so hot - around 20-22 degrees Celsius. But the car showed weird behavior. Ever since day one, it was always accelerating up to ~10-15mph on Battery and then the ICE kicks. But today no matter how slow the acceleration was, ICE was starting from 0.

Keeping constant speed on flat road in EV was also very difficult and any tiny movement in my right foot was starting the ICE.

Charging the Battery on descents was also strange - weaker than usual and even starting the ICE to decelerate (as when Battery is full) from time to time.

What might have caused this unusual behavior of the car?

 

The car stays in underground parking and on the outgoing trip it was fine. Then it stayed parked outside for about an hour and on the return started to show the above behavior.

Second trip for the day was exactly the same - 30-40 minutes in the underground parking seems cooled the car and was ok, on the return again weird.

 

 I am starting to worry what might be when the temperatures get above 30...

[Gerg]

I am sure that you already know this, but just in case you didn't - your symptoms are similar to an Auris hybrid or Prius gen3 with a clogged up Battery cooling fan.  Although on those cars a dashboard warning light will illuminate if their batteries get too hot, and an error code is logged.

Have you got anything loose in the back of the car that could silently get drawn over the ventilation grille for the Battery and prevent air flow?  This grille is likely around the rear seat somewhere.

Do you use the Hybrid Assistant app on your car?  You seem a lot more interested in the car than the 'average' driver.  If you don't have this app (which is free and runs on an Android phone or tablet, but needs an ELM 327 OBD2 dongle to operate it), then I would consider getting it.

http://hybridassistant.blogspot.com/p/about.html

The HA app, as well as giving you plenty of real-time hybrid information that you can't otherwise get displayed (Battery temperature, MG1 speed, MG2 speed etc, etc,) allows you to test and vary the speed of the battery cooling fan, which is often almost silent when on its slower (ECU controlled) speed settings, or at least HA does allow this on the older hybrids.  This won't fix your 'problem', but it might help you understand it more.  

[TonyHSD]

Hi, I agreed with Gerg , something might have blocked the Battery air vent and caused higher Battery temp, together with high air temperature outside, using an air con in the car in hot days helps a lot. There is a air filter on the air vent that needs check and clean on regular basis, older Toyota hybrids need a fan cleaning procedure too. 
Regards 

[OXYGEN]

Yes, I was driving without the AC, just the roof opened.

Nobody and nothing on the back seats, so definitely not covered vents.

Today the car stayed next to a lake for 3 hours during my sup paddling. Temperatures similar to yesterday’s and car was normal as always. But I was using the AC this time.

 

 I know the app and was thinking of getting it. But I don’t have Android phone/tablet and not sure if I buy a cheap phone just for this, it can handle the app.

[TonyHSD]

With iPhone and Carista obd 2 adaptor you can check Battery temperature, cells voltage, life, and more, but if you want you can get a cheap android that will give you some more options, Huawei P smart or P30 lite or Honor 10 can do the job perfectly. Using AC in temps over 25C is really beneficial, because the interior air is actually used to cool the hybrid Battery, full ev’s like Tesla has liquid cooling but our cars doesn’t. 
Regards 

[RabButler]

19 hours ago, OXYGEN said:

Yes, I was driving without the AC, just the roof opened.

Nobody and nothing on the back seats, so definitely not covered vents.

Today the car stayed next to a lake for 3 hours during my sup paddling. Temperatures similar to yesterday’s and car was normal as always. But I was using the AC this time.

 

 I know the app and was thinking of getting it. But I don’t have Android phone/tablet and not sure if I buy a cheap phone just for this, it can handle the app.

Just a thought, but I wonder if driving with the roof open affects the air flow through the Battery fan. If the extraction of air through the roof is sufficient to draw air into the car through the Battery cooling slot then when the fan starts up there would be nil airflow over the Battery.

[Timmon]

5 hours ago, RabButler said:

Just a thought, but I wonder if driving with the roof open affects the air flow through the battery fan. If the extraction of air through the roof is sufficient to draw air into the car through the battery cooling slot then when the fan starts up there would be nil airflow over the battery.

I should imagine Toyota have allowed for this. I don't notice any draft from the moon roof when it is open, so I am not sure how much air current really leaves the car. No worse than having a window open. It has been fairly warm on days this spring, up to 25 degrees, and the car interior has been scorching, but I have found that the car has returned to the way it was last summer. Starts on EV, and ICE cuts in around 30 mph or when the Battery needs topping up, less use of the ICE than in winter. 

It is a useful observation from as mentioned by Gerg. I bought fitted car mats from Diamond mats, and they clearly had specs from the USA market, because if I fitted them as they arrived, they would have covered the Battery cooling vents completely! Had I not been aware of the importance of these vents, I would have had problems. I cut the offending material away to leave the vents clear.

I wonder how many drivers put shopping bags into the rear floor well, and block the vent by accident?

[nielshm]

And what temperaturs are "critical" in terms of providing full performance? The very hot days with +30 C can't be be best. If the car can keep 21C in the cabin, but the air and tarmac is much warmer, I wunder what temperaturs are inside the Battery, hidden under the back seat. 

[OXYGEN]

10 hours ago, nielshm said:

And what temperaturs are "critical" in terms of providing full performance? The very hot days with +30 C can't be be best. If the car can keep 21C in the cabin, but the air and tarmac is much warmer, I wunder what temperaturs are inside the battery, hidden under the back seat. 

Yea, I am also interested.

Here, where I live, temperatures in summer go to 35+

[King Crimson]

This is indeed weird, for the past 1.5 weeks in greece the temperatures have gone up to 39 celcius and i haven't had any problems. The Battery stays on for much longer and the engine comes in much later when i turn my car on. I'm sure that toyota have though of the fact that these vehicles have to operate in sometimes harsh conditions whether that is extreme heat or extreme cold, it would be a bad design if it couldn't work in these conditions.

[OXYGEN]

6 minutes ago, King Crimson said:

This is indeed weird, for the past 1.5 weeks in greece the temperatures have gone up to 39 celcius and i haven't had any problems. The battery stays on for much longer and the engine comes in much later when i turn my car on. I'm sure that toyota have though of the fact that these vehicles have to operate in sometimes harsh conditions whether that is extreme heat or extreme cold, it would be a bad design if it couldn't work in these conditions.

Do you have panoramic roof and if so, do you drive with the roof curtain opened?
I am suspecting that in very sunny days with the curtain opened, the temperature in the cabin goes too high without AC and that was the reason for the strange Battery behavior.

[King Crimson]

1 minute ago, OXYGEN said:

Do you have panoramic roof and if so, do you drive with the roof curtain opened?
I am suspecting that in very sunny days with the curtain opened, the temperature in the cabin goes too high without AC and that was the reason for the strange battery behavior.

Unfortunately i don't have one fitted as it wasn't an option. I almost never drive with my windows open as well. It's still weird that opening the panoramic roof would result Battery problems. I think if you open the panoramic roof it would create more ventilation? I'm not entirely sure if that's what's causing the issue.

[OXYGEN]

I think the problem is not driving with the roof opened.
Probably it was leaving the car parked under the sun with roof closed, but curtain opened.

[nielshm]

1 hour ago, King Crimson said:

Unfortunately i don't have one fitted as it wasn't an option. I almost never drive with my windows open as well. It's still weird that opening the panoramic roof would result battery problems. I think if you open the panoramic roof it would create more ventilation? I'm not entirely sure if that's what's causing the issue.

If it's 35°C outside and the roof is open, the air circulating around the Battery will also be 35°C. It's does'nt feels as hot since the car's moving, but it does'nt change the actual air tempature.

With windows closed, aircon turned on, air temp. in the cabin is 21-23°C, and in the Touring Sport with air vents at the backseat, cold air is even closer to the Battery pack.

[Timmon]

13 hours ago, OXYGEN said:

I think the problem is not driving with the roof opened.
Probably it was leaving the car parked under the sun with roof closed, but curtain opened.

I would check with the dealer. You have not experienced abnormal temperatures. I doubt the roof has anything to do with anything. I have no problems, and it's been 26 here, much hotter in the car when left outside, so you have something else going on specific to your car. Maybe you have a Battery fan failure, an obstruction in air flow around the Battery, or something like that. If you were driving across the Sahara, maybe the car would behave differently, but temperatures are hardly at those levels yet. Best get it checked out before the summer starts , or as soon as your service centre reopens.