Real world range on Premium ER/AWD

[dbsb3233]

I drive a Volt. I live in Canada. I can tell you 30% for cabin heating is entirely routine in winter.

FYI I ordered a SR AWD model. Don't care about range.

Still just seems amazing to me that it would take 10,000 watts to keep a car interior heated. That's like a 1000 sf garage heater.

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[Kamuelaflyer]

Still just seems amazing to me that it would take 10,000 watts to keep a car interior heated. That's like a 1000 sf garage heater.

The Mach-e is going so fast it leaves the hot air behind and replaces it with cold air. Logic.

 

[DBC]

All I know is that people like @OutofSpecKyle who drive BEV's over 50k miles a year see a degradation in range when it's raining. You can try to "science the sh*t out of it", but if your model is incomplete and doesn't account for all the right variables then you won't get the right answer.

The observation that "if your model is incomplete and doesn't account for all the right variables then it won't get the right answer" is very much on point. It's why anecdotal impressions like "I get less range when it rains" can be misleading. I definitely get less range when it rains. But where I am it's also a whole lot colder and a lot more windy when it rains, and driving in windy conditions when it's 20F colder than normal will for sure result in less range.

Whether wet roads significantly contributes to that even at lower speeds is hard to know. What is known is that (1) for most tires on good roads rolling resistance doesn't increase much at higher speeds when roads are wet; and (2) at higher speeds rolling resistance is significantly less important than drag. If rolling resistance goes up by 20% and drag goes down by 10% (water vapor has an atomic mass of 18 whereas diatomic Oxygen and Nitrogen have atomic masses of 32 and 28), then at higher speeds you'll need less power and hence will have more range.

 

[Illinibird]

No there haven't been any test drives that would suggest the actual range. Seems like you are most interested in range on the freeway. Insideevs usually does one of those, though the guy who does them has recently moved from NC to CO so he'll have to find some nice flat roads in warmer temperatures for that to happen (I think he mentioned he was going to try and do this in CA sometime in January).

I doubt 30 miles of range will matter than much. It's not as if you plan to pull into a charging station with zero miles remaining, and the charging stations are usually spaced less than two hundred miles apart. And if you are nervous you can just slow down.

Or take your ICE car on longer trips that you have range anxiety over because the charging stations are too few and far between.

 

[ChasingCoral]

The observation that "if your model is incomplete and doesn't account for all the right variables then it won't get the right answer" is very much on point. It's why anecdotal impressions like "I get less range when it rains" can be misleading. I definitely get less range when it rains. But where I am it's also a whole lot colder and a lot more windy when it rains, and driving in windy conditions when it's 20F colder than normal will for sure result in less range.

Whether wet roads significantly contributes to that even at lower speeds is hard to know. What is known is that (1) for most tires on good roads rolling resistance doesn't increase much at higher speeds when roads are wet; and (2) at higher speeds rolling resistance is significantly less important than drag. If rolling resistance goes up by 20% and drag goes down by 10% (water vapor has an atomic mass of 18 whereas diatomic Oxygen and Nitrogen have atomic masses of 32 and 28), then at higher speeds you'll need less power and hence will have more range.

Except comparing water vapor and molecular oxygen and nitrogen are not equivalent in the atmosphere. Water vapor does not exist in the atmosphere in molecular form except at the lowest possible levels of absolute humidity. It exists as microparticulates in suspension (not solution) with condensation bringing together water molecules into larger particles. It does not displace atmospheric gases (N2, O2, CO2, and trace gases) but adds to the mass of air. Humid air is much heavier than dry air. Condensed water vapor in clouds is much heavier than air outside clouds.

Liquid water in the form of rain is much heavier and adds surface tension, increasing rolling resistance of tires (https://hpwizard.com/rolling-resistance-vs-road-wetness.pdf).

 

[balthisar]

Still just seems amazing to me that it would take 10,000 watts to keep a car interior heated. That's like a 1000 sf garage heater.

When I had my Fusion Energi, the pre-heating at 110 V was horrible. Consider that most household circuits are only 15 amps, that's only 1650 watts resistive. That's a small space heater against something that's not all that well insulated and made of a highly-conductive material. Bumping that to 10,000 watts seems reasonable in comparison.

Because I only had about 24 km of range in good weather, but a 19 km commute to my office in Dearborn, used to try to make a game of how for I could get before the ICE kicked on, so I routinely left off the HVAC and counted on the seats and steering wheel. I wouldn't subject my family to this, for short distances alone, it was bearable.

 

[Racing_Andy]

Except comparing water vapor and molecular oxygen and nitrogen are not equivalent in the atmosphere. Water vapor does not exist in the atmosphere in molecular form except at the lowest possible levels of absolute humidity. It exists as microparticulates in suspension (not solution) with condensation bringing together water molecules into larger particles. It does not displace atmospheric gases (N2, O2, CO2, and trace gases) but adds to the mass of air. Humid air is much heavier than dry air. Condensed water vapor in clouds is much heavier than air outside clouds.

Liquid water in the form of rain is much heavier and adds surface tension, increasing rolling resistance of tires (https://hpwizard.com/rolling-resistance-vs-road-wetness.pdf).

Hi everyone! I've been cruising the forum from the sidelines for a bit, but as a motorsports aerodynamicist by trade, this is my jam!

DBC's earlier post about Avogadro's Law got my attention and is correct for water vapor (not condensed water). However, the partial pressure of water vapor in the air is fairly small, so the effect of relative humidity on air density is correspondingly small. Air's ability to hold water vapor is very dependent on temperature, so I'll give two examples for context:
For air at 40 deg F, the density only drops 0.3% going from 0% to 100% relative humidity.
For air at 100 deg F, the density drops 2.5% going from 0% to 100% relative humidity.

Overall, temperature and altitude dominate air density. 40 deg air is 13% more dense than 100 deg air (at 50% RH).

Rain is an entirely different topic, and one that I know less about. I do agree that it would increase rolling resistance.

Thanks for getting me thinking this morning!
Andy

 

[generaltso]

When I had my Fusion Energi, the pre-heating at 110 V was horrible. Consider that most household circuits are only 15 amps, that's only 1650 watts resistive. That's a small space heater against something that's not all that well insulated and made of a highly-conductive material. Bumping that to 10,000 watts seems reasonable in comparison.

If the heater can use 10kW, I hope the car is smart enough to dial it back to match the charging speed during preheating. It would suck to have to use some of the battery to make up the difference when you're plugged in to a 7kW charger. I have this problem with my Outlander PHEV. The charger is only 3kW, but the heater is 4kW. So if I preheat while plugged in, it still always uses some of the battery. I hate that.

 

[mr_raider]

Still just seems amazing to me that it would take 10,000 watts to keep a car interior heated. That's like a 1000 sf garage heater.

You don't have time component in your calculation. How long was the heat on?

There are three issues:

1. If your vehicle has been garaged outside, the battery will be cold. EVs with an active coolant loop will heat the battery pack. I assume Ford will do this as GM does, and not the use a Tesla style hack. This eats energy.

2. You need to get your cabin up to temp. That means the cabin and interior need to absorb enough heat to reach the desired temp.

3. Ongoing heating to maintain the cabin temp. This is much less than 2, but will accumulate over a drive.

1 and 2 are "front loaded" at the start of the drive, but can be mitigated by garaging, or preconditioning off the 240v L2.

3 is an ongoing drain and depends mostly on the outdoor temp and your personal tolerance to frozen dingle berries. Heated seats help.

Note that my car has a range of 83km base at around 4C, but drops to 55km at -9C. The resistive heater in the Volt can draw up to 6kW, and the car has a useable 15kwh battery capacity. You do the math. Fortunately, the heater will cycle on and off periodically in bursts to maintain cabin temp. But the first 10 mins after a cold start is brutal. Plus sometimes we run our heater at idle here just to melt the snow and ice off the car windows.


Below -10, GM chose to give up and solve issue 1 and 2 by running the gas engine.

If you wish to discuss heat pumps we can do that too. My house is exclusively heated by electricity.

 

[dbsb3233]

You don't have time component in your calculation. How long was the heat on?

That's the $64,000 question. If it uses 10kw for heat for just the first 5-10 minutes (30% of the MME energy consumption doing 70 MPH on the highway when it's cold out), and then drops to 3 kW to maintain from there (10% of the MME energy consumption), then fine.

But a few of the (admittedly scant) clues so far suggest 30% may be the number throughout. Which would be a killer for range on a long road trip when it's not a perfect 70F outside.

We really need to see more real-world examples that show energy consumption 15 minutes in, and an hour in, etc. Or better yet, for a full road-trip leg between charges.

 

[silverelan]

I want to know the MME 4X range after 30 minutes of DC fast charging.

Thanks to Kyle Connor, we know the Audi e-tron can do 180+ miles at 70mph. We also know from Bjorn Nyland, the e-tron will charge up from 10% to 80% in 26 minutes. Thus, the e-tron will get ~125 miles (+/- 5) of 70mph range in 26 minutes of high-powered charging.

Would the MME AWD ER keep pace with the e-tron if limited to the same amount of time charging?

 

[mr_raider]

That's the $64,000 question. If it uses 10kw for heat for just the first 5-10 minutes (30% of the MME energy consumption doing 70 MPH on the highway when it's cold out), and then drops to 3 kW to maintain from there (10% of the MME energy consumption), then fine.

But a few of the (admittedly scant) clues so far suggest 30% may be the number throughout. Which would be a killer for range on a long road trip when it's not a perfect 70F outside.

We really need to see more real-world examples that show energy consumption 15 minutes in, and an hour in, etc. Or better yet, for a full road-trip leg between charges.

Yeah I wouldn't worry.

Many Canadians have years of experience with the FFE which has pathetic range at baseline. They manage fine in winter. Due to the active battery heating, I suspect the Ford will see less range degradation than the TM3 in extreme cold.

Psychologically I am full prepared to see less than 200km of range in winter on my SR AwD. I knew that when I plopped down my deposit.

 

[agoldman]

You don't have time component in your calculation. How long was the heat on?

There are three issues:

1. If your vehicle has been garaged outside, the battery will be cold. EVs with an active coolant loop will heat the battery pack. I assume Ford will do this as GM does, and not the use a Tesla style hack. This eats energy.

2. You need to get your cabin up to temp. That means the cabin and interior need to absorb enough heat to reach the desired temp.

3. Ongoing heating to maintain the cabin temp. This is much less than 2, but will accumulate over a drive.

1 and 2 are "front loaded" at the start of the drive, but can be mitigated by garaging, or preconditioning off the 240v L2.

3 is an ongoing drain and depends mostly on the outdoor temp and your personal tolerance to frozen dingle berries. Heated seats help.

Note that my car has a range of 83km base at around 4C, but drops to 55km at -9C. The resistive heater in the Volt can draw up to 6kW, and the car has a useable 15kwh battery capacity. You do the math. Fortunately, the heater will cycle on and off periodically in bursts to maintain cabin temp. But the first 10 mins after a cold start is brutal. Plus sometimes we run our heater at idle here just to melt the snow and ice off the car windows.


Below -10, GM chose to give up and solve issue 1 and 2 by running the gas engine.

If you wish to discuss heat pumps we can do that too. My house is exclusively heated by electricity.

geeze, I guess gone are the days of just get in and drive . . . I'm old enough to remember when you had to warm up the car a bit before taking off. Seems like we are right back there again.

 

[dbsb3233]

Many Canadians have years of experience with the FFE which has pathetic range at baseline. They manage fine in winter.

"managing fine" is subjective though. And frankly, I think the average consumer expects more from a $50k+ car that "managing". I know it can be done in most cases. What I'm more interested is quantifying the degree of range degradation to expect on long trips using the heater.

I know some people will manage with just using heated seats and steering while, while managing a cold nose, lips, ears, and feet. But I know most won't settle for that. Thus why the amount of loss matters.

 

[Guy]

This is an issue on the Polestar 2. No battery pre-heating available on that car and users are reporting huge battery draw in the first 30 minutes or so of driving; after that it settles a bit. Reports indicate 1% battery loss per mile for the first 10 miles.

Also saw yesterday a note to Ford dealer to fully charge and precondition the cars before delivery and to remind customers of the importance to pre-condition the car to optimize range.

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