Apple Maps Preconditioning

[AZBill]

Don’t feel like watching it. Can you give me the cliff notes and tell me how long it took to heat up before it started charging? Resistive heaters heat faster with more amps, no? Maybe not but i was alluding to the situation where, while the car is driving down the road, there’s X amount of power available to both drive and heat while at the DCFC there’s probably much more available to heat first then charge. If in fact, if the heater only runs at a fixed power level then, yeah, it doesn’t matter the source as long as it’s at least that much.

It took almost 45 minutes to warm the battery, it was drawing 5-7kw (from the charger) to warm the battery during that time. That is about the same range of power the heater in the Mach E has. Obviously if driving the battery will already get above freezing, but it needs to get up to at least 70F to get full fast charging rate. And once his battery did start the charge, it was at about 30kw initially.

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[Tampamike]

It took almost 45 minutes to warm the battery, it was drawing 5-7kw (from the charger) to warm the battery during that time. That is about the same range of power the heater in the Mach E has. Obviously if driving the battery will already get above freezing, but it needs to get up to at least 70F to get full fast charging rate. And once his battery did start the charge, it was at about 30kw initially.

So, about 6kw/hr rate for the heater driving or sitting. That’s 4.5kw’s burned for 45 minutes. MachE pre-conditions for roughly, only 20 minutes while driving - 2kw’s burned. At arrival you‘ll still need another 25 minutes to warm it up all the way or maybe more since it’s probably not as warm with 20 minutes of pre-conditioning while flying down the highway at 75 mph of cooling airflow than it would be with 20 minutes of sitting on a plug. So let’s say you still need 30 minutes of heating on the plug. Then you’ll need another 5 minutes, say, to replenish the kw’s used in pre-conditioning for a total of 35 minutes. So, net result, about 10 inutes saved by pre-conditioning.

 

[ChrisO]

So, about 6kw/hr rate for the heater driving or sitting. That’s 4.5kw’s burned for 45 minutes. MachE pre-conditions for roughly, only 20 minutes while driving - 2kw’s burned. At arrival you‘ll still need another 25 minutes to warm it up all the way or maybe more since it’s probably not as warm with 20 minutes of pre-conditioning while flying down the highway at 75 mph of cooling airflow than it would be with 20 minutes of sitting on a plug. So let’s say you still need 30 minutes of heating on the plug. Then you’ll need another 5 minutes, say, to replenish the kw’s used in pre-conditioning for a total of 35 minutes. So, net result, about 10 inutes saved by pre-conditioning.

without actually doing a apples to apples comparison I don’t think you can draw that kind of straight conclusion.

And note that this was a worst case scenario since he purposely left the car their for two days to make sure it was totally frozen.

Personally I will never need this, but if I did I would go with the experts, they wouldn’t have out in such a feature if it was a zero sum case.

 

[music_cities]

I envision:
two of the same cars
parked overnight in the same place so starting battery temps are identical
100% starting charge
coldish weather
arrive at the same Tesla SC at the same time
one has been navigating to a very nearby EA in order to initiate pre-conditioning and one hasn’t (no pre-conditioning)

What would be the difference in arriving charge level?
What would be the difference in time to 80%?

Maybe this experiment has already been done -probably …

Come visit Calgary this winter and we'll do a comparison together.

 

[Tampamike]

without actually doing a apples to apples comparison I don’t think you can draw that kind of straight conclusion.

And note that this was a worst case scenario since he purposely left the car their for two days to make sure it was totally frozen.

Personally I will never need this, but if I did I would go with the experts, they wouldn’t have out in such a feature if it was a zero sum case.

So, if this is worst case, then most cases would be less of a difference, no?

It’s not zero sum, apparently. My back of the napkin came up with 10 minutes. Manufacturers have to have a battery heater or else you wouldn’t be able to charge below freezing. The pre-conditioning just gets it started earlier and probably doesn’t cost a thing in design or assembly, just software. I’m still thinking it’s not as big of a deal as some think, kind of like the frunk or Apple CarPlay. But hey, if you want to carry that torch, have at it. I’ll bow out now.

 

[Tampamike]

Come visit Calgary this winter and we'll do a comparison together.

With a hot bowl of poutine? Or don’t you guys eat that out we…..

 

[ChrisO]

So, if this is worst case, then most cases would be less of a difference, no?

It’s not zero sum, apparently. My back of the napkin came up with 10 minutes. Manufacturers have to have a battery heater or else you wouldn’t be able to charge below freezing. The pre-conditioning just gets it started earlier and probably doesn’t cost a thing in design or assembly, just software. I’m still thinking it’s not as big of a deal as some think, kind of like the frunk or Apple CarPlay. But hey, if you want to carry that torch, have at it. I’ll bow out now.

As a programmer I take exception to the concept of “it’s just software”. Software doesn’t just pop into existence. If you set your developers to work on a useless piece of software that is time taken away from them developing other features. So, I really hope the feature isn’t worthless.

To me this feature is only “academic“ since I don’t need it, so I’m perfectly willing for it to go either way. But speculation with no tests to back it up isn’t going change anyone’s mind.

 

[Tampamike]

As a programmer I take exception to the concept of “it’s just software”. Software doesn’t just pop into existence. If you set your developers to work on a useless piece of software that is time taken away from them developing other features. So, I really hope the feature isn’t worthless.

To me this feature is only “academic“ since I don’t need it, so I’m perfectly willing for it to go either way. But speculation with no tests to back it up isn’t going change anyone’s mind.

It’s speculation on the speculation. Lots of people scream for pre-conditioning. I haven't seen any tests to compare with or without and what it might get you - only speculation or assumption. I just started thinking, ya know, there’s no such thing as a free lunch. Kilowatts is kilowatts. When they go out you have to put them back in. No disrespect to you software engineers - you are very valuable. I’m not trying to change anyone’s mind, just trying to validate things in my own mind. So far, it’s only been more speculation. I’m willing to move on, since it’s academic foe me also.

 

[dan_meh]

@Tampamike asked for a side by side. Here goes:

And so that you don’t need to watch it, a summary: two ID.4’s same state of charge. Cold weather. One driven normally to a charger. One “yo-yo’d “ to the charger to simulate preconditioning.

The yo-yo car charged much faster. 19 minutes to 60% vs one hour to 60% for the cold battery.

Hope that helps!

I feel like this thread has turned into an intervention .

 

[ChrisO]

I came back to report I did find such a test, looks like @dan_meh beat me to it but I will post mine because it is text with a graph.
https://insideevs.com/news/699912/supercharging-tesla-winter-preconditioned-vs-cold-battery-test/

And if you are into theory this such a paper. Interesting driving faster does reduce the advantage, but not because of cooling, because of heating and that cars charge faster if the SOC is lower, which it will because the less energy efficient driving.

One thing that is clear to me by this paper is that this is a very complex problem and tends to point out that maybe a pre-condition button is not as a clear cut fix to the main problem discussed here where Car Play isn’t cooperating with the car. Ideally according to the paper the car needs to take into many things not just turn on the heater some time/distance from the charger. See the conclusions at the end.
https://www.mdpi.com/2032-6653/15/8/377

 

[Tampamike]

@Tampamike asked for a side by side. Here goes:

And so that you don’t need to watch it, a summary: two ID.4’s same state of charge. Cold weather. One driven normally to a charger. One “yo-yo’d “ to the charger to simulate preconditioning.

The yo-yo car charged much faster. 19 minutes to 60% vs one hour to 60% for the cold battery.

Hope that helps!

I feel like this thread has turned into an intervention .

See above post. Video test (not scientific) determined difference was 10 minutes and of course would cost more. Technical paper (way scientific) - it’s complicated (I couldn’t read the whole thing in one sitting). Kyle’s test had some inequalities - different charger power, yo-yo driving, cabin heat. It wasn’t designed to compare what we are talking about here since ID4 doesn’t even have pre-conditioning. It was more to prove his theory of yoyo driving to heat up the battery.

Whatever. I’ve said this before, I think I’m done. I will concede that pre-conditioning will allow for faster charging. I’m sticking by the idea that it’s probably not as huge of a deal as some would say but it’s a good idea and a good thing to have. In my life I’m not worried about out it. I still love my car and I hope you do to. Cheers!

 

[ChrisO]

Here is my final thoughts, I tend to agree that people make more out of it than Is really happening, but doesn’t surprise me. It has been shown many times that a cashier can check out people faster than self checkout, but because like them because they are the ones doing it they feel like it is faster. (And stores like them because they can’t hire less people). This just how people view the world.

The simple fact that it is being done while they are driving makes them feel better, even if it saved zero time. And in some cases it will save time at the charger, they care more about that than saving energy/money.

But on top this looking at what the paper said needs to be taken into account a manual button doesn’t sound like the fix all I first thought it was. As with most things people tend to think problems are far simpler than they really are and wonder why it takes developers so long to implement them. In this case it seems to me distance to the charger is critical and that would have to come from Car Play.

 

[Blitzen]

Does pre-conditioning really save any time? I don’t have any experiential evidence to introduce but it seems to me it’s robbing Peter to pay Paul. You’re driving down the road and the battery heater has to use electrons from the battery to heat the battery. You arrive at the charger with less electrons than if it didn’t heat the battery thus requiring longer to charge to replenish the greater amount of lost electrons. If you don’t pre-condition, you arrive at the charger with more electrons and a cold battery requiring the charger to supply the electrons to first heat the battery. As I see it, the amount of electrons needed for heat and charge is the same no matter where it comes from or in what order they’re produced. So, I’m thinking the DCFC produces those electrons faster than the battery does for the heat portion and thus the net result is a faster charge without pre-conditioning.

Am I crazy? Or has this been proven that pre-conditioning leads to a faster charge?

Just spitballin’.

In Florida it wouldn't matter much. But for those us that drive South to get to Canada, it saves a lot of time. I don't notice the energy loss but on a winter road trip the car is ready to go after our usual pit stop routine just like in summer. With range sometimes half what we get in summer, there are twice as many charging stops so it helps that at least the time stopped is about the same. Even with the reduced range, our Mach-E is so much better than anything burning dino juice on a cold day. So comfy with pre-heating, quiet, and smooth. And I spend less time at charging stops than I used to pumping gas (no fun in a blizzard!).

 

[AZBill]

One thing that is clear to me by this paper is that this is a very complex problem and tends to point out that maybe a pre-condition button is not as a clear cut fix to the main problem discussed here where Car Play isn’t cooperating with the car. Ideally according to the paper the car needs to take into many things not just turn on the heater some time/distance from the charger.

The intent of the button is only to tell the car it needs to get ready to charge, not to just "turn on a heater" and leave it on. The software figures out what temp range the battery needs to be at (normally 70-100F). Also, the battery may need to be cooled, rather than heated, for example in the Arizona desert where I live.

The truth is, Ford's implementation is poor, it is not really starting the conditioning soon enough, as compared to other EVs. In my other two EVs, it tells me when the battery is ready, and in mild weather that occurs not long after the conditioning starts. Both of them also have the manual button to tell it to get the battery ready, that is useful when there is a new charger that is not yet in the nav database.

 

[Mach-Lee]

The truth is, Ford's implementation is poor, it is not really starting the conditioning soon enough, as compared to other EVs. In my other two EVs, it tells me when the battery is ready, and in mild weather that occurs not long after the conditioning starts. Both of them also have the manual button to tell it to get the battery ready, that is useful when there is a new charger that is not yet in the nav database.

Agree, Ford's implementation only starts the battery heating 30 km from the charger, at freeway speed that's only 15 minutes of possible heating time. That is not nearly long enough, especially in the winter when the cabin is using most of the heat output. It should start more like 45-60 minutes out (or about 100-120 km) from the charger to have a better chance of being effective. That's what other EVs do, Ford just severely limited it for reasons that don't make sense to me.

The engineers were excessively worried about range loss, but seem to have not done the math to support it. Worst case, the 30 km geofence will use at most 2% of the battery pack for preconditioning (no big deal). In most cases it currently uses less than 1% additional. It should allow you to use up to 5% of your battery for preconditioning. The nav has a large enough buffer (e.g. 20% arrival) that an additional 5% loss is not a significant problem.

To my knowledge they still haven't fixed the limited 30 km range of preconditioning, which severely limits its effectiveness. I'll test it again this fall.

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