Stays in Series mode at 70mph

[ThudnBlundr]

Yesterday it was sub-zero and I preheated the car before we set off. Within 5 minutes we were on the motorway, where we drove at a steady 70mph (actual) for an hour. The engine never entered Parallel mode, staying in Series the whole journey, even when we turned off onto slower roads. I tried pressing the CHRG and SAVE buttons to see if they did anything, without success. The economy was around 33mpg, which is far worse than we usually achieve. On the journey back later in the day, it went into Parallel as usual. I remember it doing the same when driving back from skiing earlier this year; it was only after an hour or so when we stopped at the border crossing for 5 minutes that it started behaving normally again.

Now our PHEV has done 93k miles and shows ~12 miles on the GOM in the cold. Is there an issue where an old, cold battery won't allow Parallel mode?

 

[Hasenphever]

Series mode is ICE charging battery, battery powering electric motor correct? This should be the normal operation but when the battery is warmed up the ICE should turn off.

Parallel mode is ICE powering front axle + battery powering front and possible rear axles correct? This should only occur when lots of power is called such as stomping on the accelerator. When you referred to parallel mode, did you mean it automatically switching to EV mode?

 

[joaquin3421]

I have experienced something similar, the parallel mode does not engage when the threshold velocity , or even higher, is reached. In my case it is correlated to the level of charge, if the battery meter shows more than 8 out of the 16 bars it doe snot enagge, wityh a discharged battery it does. Do you have readings of the battery capacity %, for example from PHEV Watchdog? Mine is at State of Health 48%, when it was above 50% the anomaly did not happen.
Temperatures can play also a role.. the behavor of this car is somethimes difficult to predict.

 

[kpetrov]

Series mode is ICE charging battery, battery powering electric motor correct? This should be the normal operation but when the battery is warmed up the ICE should turn off.

Parallel mode is ICE powering front axle + battery powering front and possible rear axles correct? This should only occur when lots of power is called such as stomping on the accelerator. When you referred to parallel mode, did you mean it automatically switching to EV mode?

Hasenphever,
You are somehow correct, Parallel mode is ICE powering front axle and Series mode is ICE turning generator and charging battery and electric motor.
Parallel mode is the most efficient way of using ICE in such vehicles. If travelling out of battery range and the use of ICE is necessary you better be in parallel mode as most efficient one. In Series mode there is more losses.
In Parallel the rear el. motor helps when power demand is requesting it, but Parallel mode is not called when stomping on the accelerator. Even the opposite, if you stomp on the gas you may exit parallel mode to get the maximum from the generator and ICE.

To the original question... Parallel in matter of fact will depend on battery charge (should be below 80%) battery SOH and ambient temperature as joaquin3421 mentioned already.

 

[ThudnBlundr]

Thanks all. I posted this on the UK FB page around the same time and got quite a few replies, but none here till now. It seems it's not that uncommon, especially of your battery's SOH is low. Mine was at 65.8% at the time, though a DBCAM has "recovered" it to around 70 (claim in dispute). It seems to be the combination of cold and low SOH; and switching into SAVE before the battery's empty means that the battery doesn't have a chance to get warm. When we stopped at the border last winter, the battery had a chance to warm slightly, which is why it then worked.

Experimentation has shown that I can achieve parallel (at least at Yorkshire cold temperatures) by emptying the battery and then using CHRG if I want to keep some charge in reserve for later. We're off to the Pyrenees and the Alps next week, so I should be able to tell you if it works at colder temperatures and slightly higher SOH.

 

[kpetrov]

BTW how stopping at the border is warming slightly the battery?

 

[littlescrote]

BTW how stopping at the border is warming slightly the battery?

Lack of cold airflow and a bit of heat soak.

 

[ThudnBlundr]

That's what I figured was happening

 

[motco]

I've had mine for only about six weeks and yesterday was the first time I had to use a motorway. Up at the legal maximum on an undulating motorway with fairly low charge level, mine dropped into what appeared to be pure parallel mode inasmuch as the graphic with the three components shown had power flowing from ICE to wheels but no other power pathway shown. It was set on 'NORMAL' mode. As an aside I was impressed with how little noise from the engine made its way into the cabin - more tyre and wind noise was apparent.

 

[ThudnBlundr]

That's what should be happening. On mine it doesn't in (UK) cold weather unless I heat the battery up by emptying it first. We're off to the Pyrenees then the Alps tomorrow, so we'll see if that still works in lower temperatures.

The ICE will usually attempt to charge the battery in Parallel, but will only do it if there is a surfeit of power; so you should see the arrow between the ICE and the battery fairly frequently. Of course this won't happen under heavier loads, and you may well see the arrow from the battery to the wheels as well to supplement the ICE.

 

[littlescrote]

I experienced a similar issue for the first time in mine this last week on a winter trip to the mountains. For reference, 2016 MY, 95k miles.

It was -6degC in the morning when setting off and on the motorway at around 75mph it would not enter parallel mode, neither in Charge nor Save. However, increasing the road speed to 84mph then it did, but ticked back out when slowing down. I can only imagine that it's related to the engine power available at the engine speed correlating to those road speeds, given that it won't allow much power top up from the battery in the cold conditions. Fuel consumption in series mode at that speed was horrific, you could almost see the gauge going down! I didn't get any data, I was rather busy dealing with a snowy German autobahn.

I stopped shortly after and set off again, but still the same behaviour. Later in the day it did then behave more normally. I don't know if it was because the battery had warmed up through use, because I'd stopped a few times/slowed down, because the ambient increased a little etc. Or perhaps a combination of all.

At the end of the day, it's a hybrid and does what it does. Such situations are rare enough for me that I don't really care, but I can imagine that if you drive in a consistently cold climate for months on end, that behaviour is going to frustrate as it seems to use a lot more fuel than you'd like. But it's a consequence of not having good battery thermal management for both heating and cooling, in combination with a small battery typical of a PHEV.

 

[ThudnBlundr]

We've just come back from a trip the French Pyrenees, followed by the Italian and Swiss Alps. We had temperatures down to -16C. My trick was to make sure that the car was well-charged by the evening - relatively easy when descending from the resorts to our apartments. Climbing back to the resort it tended to use the ICE fairly heavily, so the lack of parallel didn't really matter. On the transfer days, letting the full-ish battery discharge normally meant that it did drop into parallel eventually, so the longer days were more fuel-efficient. We weren't able to charge much from the mains, so the consumption did vary considerably