Long trip / cold start

[Petzi]

I think that there are two somewhat independent things going on in cold weather. First, the car consumes more to heat the cabin and presumably to manage the battery. Second (and I am, less sure about this) the battery looses effective capacity in the cold. The battery likely loses efficiency in the cold, so it cannot deliver all the energy that was stored into it, so range is reduces as electrons are lost in the cold battery. This would imply that the range can be improved if the battery is preconditioned before departure, more so if the car is plugged in before leaving so the preheating is powered by the charger and not the battery. So in the summer, you can estimate range given the consumption (assuming the battery is able otherwise deliver all its capacity) and you would see a lower range in winter (even if consumption is the same) in winter. Combining more consumption to heat people/machine and lower effective battery capacity means a double hit to range.

1) air density: up to 20% more consumption (suv)
2) rolling resistance 15-30% higher at 0 C (32 F) than at 20 C (68 F)
2) heating (cooling) up to 6kw/ hour (no sense to waste energy on preheating of battery before a drive)
3) battery loss has minimal impact on range, but significant impact on performance. both too hot or too cold. therefore sport + starts preconditioning right away.

everybody can test this in engaging sport+ in very cold weather.

(in your case it was the charger)

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[dbsb3233]

I have posted this over and over again:
- I posted a video that shows that the energy spent on warming up the battery has a positive outcome, the battery will be able to give more energy than what the pre heating spends ... that was done with a Skoda but that doesn't matter.
- yes program a DC charge point and sit in the car, at that temp it probably is more like an hour
- DC charge at nearest DC charge point
- as you cannot AC charge overnight you will loose a lot of heat ...

When starting to drive use the PCM you want to have the time to heat the battery ...

I personally have done this and works ... my consumption is less with preheating and heated battery and the range is only impacted by the colder air ... making 350+km possible in the cold ...
and saving at least 30 minutes at the first stop as DC fast charging will rip to 270kw ...

That may very well work, but I'd only bother with all that if my DCFC options were so limited that I *had* to do it. Otherwise I'm just preheating the cabin before leaving in the morning and going like normal, letting the car precondition the battery for a distant DCFC stop that the car can safely reach in normal order. Accepting that it's not going to be an efficient leg and may cost me $2 extra in kWhs. Just not worth the extra effort to roll out of a hotel bed early and throw on some clothes just to go out to the car in freezing cold an hour early to start the nav to get it to preconditioning the battery right away.

Unless I *have* to find a way to save 5 kWh in order to safely make it to the next DCFC, I'm not inclined to jump through those hoops.

Now, if the app had a way to precondition the battery, that would be great! I'd just hit it when I wake up in my hotel room before hopping in the shower like I do now with cabin heating. But sadly, that option doesn't appear to exist. Unless setting a departure time does that, but I don't think it does. I did set a departure time on our last freezing trip, and while the outside temps were 18F, the car battery showed 30F. I'm guessing that wasn't actually battery heating though, but instead just a little nearby heat radiating from the cabin floor.

 

[Petzi]

PREHEATING OF BATTERY (EXCEPT FOR CHARGING) COST MORE ENERGY tHAN DRIVING WITH COLD BATTERY.
Why is this so hard to accept?
The stubbornness of some is the reoson why porsche does not allow manual conditioning of battery.

 

[Yves]

PREHEATING OF BATTERY (EXCEPT FOR CHARGING) COST MORE ENERGY tHAN DRIVING WITH COLD BATTERY.
Why is this so hard to accept?
The stubbornness of some is the reoson why porsche does not allow manual conditioning of battery.

 

[TomekGnomek]

PREHEATING OF BATTERY (EXCEPT FOR CHARGING) COST MORE ENERGY tHAN DRIVING WITH COLD BATTERY.
Why is this so hard to accept?
The stubbornness of some is the reoson why porsche does not allow manual conditioning of battery.

I think a lot of people overthink this.

This is especially true in winter as there is no better way to calculate when to charge, how to charge, how to preheat etc than using the route planner. You simply cannot do it on your own and take into account things like elevation change with sudden drop of temperature - like when going skiing to the mountains. I observed this on my last mountain trip in December how the PCM can calculate and perfectly adapt the route, stops etc given the sudden change in conditions and my desired SoC at the destination which was a hotel without a charger. It really works very well and is quite sophisticated beyond anything you can do on your own. In the end the arrival time and SoC at destination is incredibly precise.

Just set the destination, departure time, plug at home before departure, forget everything and just enjoy driving.

 

[Petzi]

@Yves : conclusion: no real benefits if you preheat.
600 watts more through regen in a (one!!) live test.
dont you think that porsche did test this thoroughly and hundrets of time and came rightfully to the conclusion that there is no benefit in it?

 

[Yves]

@Yves : conclusion: no real benefits if you preheat.
600 watts more through regen in a (one!!) live test.
dont you think that porsche did test this thoroughly and hundrets of time and came rightfully to the conclusion that there is no benefit in it?

+ the fact you loose an additional 20 to 30 minutes on your first charge with a cold battery
+ the fact that you induce less wear/degradation on the battery
+ you get more range so nullifying the energy used to preheat …

Anyway I think I have proven that my overall energy consumption at 130km/h in colder conditions over 1000km is less than average.
To each their own, but if I can save my battery from degradation, charge at max speed at my first stop and have more ar at least no penally because of pre heating I know what I prefer, you do you … Floor your car with a 0C battery

 

[Petzi]

@Yves

+ the fact you loose an additional 20 to 30 minutes on your first charge with a cold battery
- no! neither the topic of this test nor true if you use the charging planner

+ the fact that you induce less wear/degradation on the battery
-absolutely no proof of this anywhere

+ you get more range so nullifying the energy used to preheat …
-same range

 

[dbsb3233]

+ the fact you loose an additional 20 to 30 minutes on your first charge with a cold battery

Unless you start the day with 80%+ like most would on a road trip day. By the time you reach your first DCFC, the car has had plenty of time to precondition the battery for the first charge.

You're not making it 200 miles that first leg on a cold battery, of course, but there's still plenty for at least 100 miles (~90 minutes).

 

[Yves]

@Yves

+ the fact you loose an additional 20 to 30 minutes on your first charge with a cold battery
- no! neither the topic of this test nor true if you use the charging planner

+ the fact that you induce less wear/degradation on the battery
-absolutely no proof of this anywhere

- Plenty of proof, if not why is regen and or charging limited when battery is cold, because it will accelerate damage/degradation ...
- using the plan, Ah so you do use preheating
- the video and my test show clearly more capacity, for instance when I do a capacity measure with my iX (a shame you cannot do this with Porsche) I see 5 to 8kwh less when the battery is cold

 

[Yves]

Unless you start the day with 80%+ like most would on a road trip day. By the time you reach your first DCFC, the car has had plenty of time to precondition the battery for the first charge.

You're not making it 200 miles that first leg on a cold battery, of course, but there's still plenty for at least 100 miles (~90 minutes).

Agree and if you can start with a warm battery your gain will be like 5 minutes max, and less strain on the battery when you rip the car through the
I did the test on a 1000km trip one departing with a warm battery and one with a cold battery coming back.
But some claim that pre conditioning eats more battery than you gain, and not needed, and that is simply not through ... the battery will never gain enough C to fast charge ... tested that as well.

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