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Does that mean if you leave your HVAC off and remote start the car, it will warm the battery on demand?
No, ignition on with the key fob the normal way. Remote start is different.
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Aramis76

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The windows fogging up every time the damper closes is, to me, a problem.
I understand why they decided to do it, but their solution sounds like it was not properly researched.
It should take into account cabin humidity and outside temp.
As an example, the last week where i live the temp is around -5c (23F) and the windows will fog up badly when those damper events happen.
Since it's not really super cold, the heater at those temps could easily (though over longer time) overtake this temperature.
The fact that Ford programmed those damper closings means i have to either crack a window every time or jump on the defroster speed every time.

I hope they fix this, it's a major annoyance. Maybe at the very least they should give us a choice to have to damper set to auto or stay where we want it?
 
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En-Route Battery Preconditioning for DCFC

Today's test is the new en-route battery preconditioning feature introduced in Power-Up 3.6.2. The idea is to heat the battery while you drive to the charger so it can accept charge at a higher rate. You must select a DC charger in the Ford Nav and be within 30 km (19 mi) of it before preconditioning will occur.

To set the stage here, it's a below 0ÂșF day here. I Level 2 charged all day at work, and even though I was charging the battery still cooled off to -8ÂșC (18ÂșF) by quitting time. I input the local EA station into the nav, and I heard the battery heating start. However it shut off shortly after taking off. Because it's so cold, the cabin heater was taking too much power and preconditioning was cancelled. Bummer. Until I had the bright idea of turning OFF HVAC. Well, that worked, fired the battery heating right up.

Now a normal person probably would have called it quits after a few minutes of no cabin heat in these pleasant -19ÂșC (-2ÂșF) temps, but I'm not normal. Yes, I suffered for science đŸ„¶ in order to see how long it would take to heat the battery up for DCFC, and how high it would go. The short answer is it took AN HOUR AT FULL HEATER OUTPUT to reach the 26ÂșC target temp for DCFC. An hour seems much longer when you're freezing. To get around the 30 km geofence limitation, I drove in circles on the highways surrounding the charger. I could have parked it and went inside, but I wanted the airflow under the pack to simulate real-world cooling effects on a highway. BTW, to avoid the windows fogging up, you need some air movement, so I ended up setting the cabin temp on LO with the fan on speed 1. That disables cabin heat and blows raw outside air at you. That helped make a pretty graph that wasn't disrupted by repeated defrost cycles, and it also helped the cabin cool down to 15ÂșF while I was driving. I was very happy to see the heater finally shut off, and immediately switched the cabin heat back on as I made my way to the EA station for DCFC.

So let's take a look at the temperature graph:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] En-route Battery Preconditioni


Focus on the blue line which is the main pack temp. In 61 minutes it went from -8ÂșC (18ÂșF) to 26ÂșC (79ÂșF). The heater output started at 6.2 kW and gradually declined to 5.6 kW (this is the PTC effect as the coolant return temp increases). Keep in mind this graph really represents the fastest you could possibly heat the battery in these conditions, the amount of heat available with the HVAC on simultaneously will be quite a bit less. If the HVAC was on at the same time, pack heating likely would have taken two hours and would have run into a wall before reaching 26ÂșC. Perhaps it would have only reached 5ÂșC. This is why it was disabled due to limited heat reserve. I will need to wait for a warmer day to test battery preconditioning while the cabin heat is still active, but the rate of heating will be significantly less.

Now let's look at the DCFC session at a 150 kW EA station I reached shortly after battery heating finished:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Preconditioned DCFC Sessio


Temp was down to about -20ÂșC/-4ÂșF when I pulled in. A lot of the chargers were displaying a "power reduced" message. I chose one not displaying the message, and activated with Plug & Charge. However I immediately noticed a 196A max current limitation (blue line), much less than the 350A these stations should be capable of. I wasn't happy with only 62 kW, so I decided to try a different dispenser. This one allowed up to 236A which was an improvement, but still slower than it should be. Not sure how much the cold affects these things. The car was correctly asking for full amperage (red line) at first, but the stations always supply (green line) 10-20 amps less than requested for some reason.

After reaching about 59%, the car decided to start requesting less current from the charger, you can see the red request line start decreasing. This is frustrating because the battery is warm enough and perfectly capable of handling the full 236A all the way up to at least 75-80% SoC. Ford has this weird charging strategy where they set the remainder of the charge curve based on the initial rate. Almost like it's a percentage of the initial rate. This means if you use a slower charging station, it will slow you down that much more for the rest of the curve based on the initial speed. This is totally not necessary, there should be a calculated maximum rate at each % SoC based on the battery temps. When using a slower DCFC station (<80 kW), it should be pegged at maximum output the whole way to 75-80%. At only 218A, no part of the battery should be getting that hot so I just don't see the need to throttle it. Ford should work on this strategy because they are needlessly reducing the charging speeds at lower power DCFC stations.

During the DCFC session, the battery was not heated any more by the PTC heater. I shut HVAC off to make sure, nothing happened. I've seen some cases where it heats more than 26ÂșC after starting a session, the decision to heat more must be tied to the charging power available. In this case heating more wasn't necessary for the speeds I was charging at. Temp increased from 23ÂșC to 26ÂșC on its own during the session (yellow trace at the top).

Findings:
  • Battery took 1 hour to heat from -8ÂșC to 26ÂșC using full 6 kW heater output (34ÂșC/hr)
  • Battery heat capacity is 0.18 kWh/ÂșC or 630 kJ/ÂșC
  • Preconditioning starts as soon as a DC station within 30 km is selected in the Ford nav
  • There is no time limit on battery heating as long as you remain within 30 km of the station
  • There is a 26ÂșC upper temp limit
  • En-route preconditioning will not occur at extreme cold temps unless you turn off HVAC
  • Many EA stations operate with significantly degraded performance
  • EA stations output 10-20 amps less than requested by the car
  • Additional heating above 26ÂșC while DCFCing is not always commanded
  • Ford throttles back the charge rate unnecessarily at lower-amperage DC stations
Conclusions:
  • The Mach-E needs a dedicated 5 kW battery heater that is not shared with the cabin.
  • Battery temp increase will be limited with only a 30 km range limit.
    • I think this limit should be increased to 60-120 km to give enough time.
  • EA stations are in varying states of disrepair
  • Ford should fix unnecessary throttling of low-amp DC stations and allow full current up to 75-80%. The current limit at 50-75% should not be affected by the initial station amperage unless using a high amperage (300+) station.
 
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Added index of tests in this topic to post #1.
 

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En-Route Battery Preconditioning for DCFC

Today's test is the new en-route battery preconditioning feature introduced in Power-Up 3.6.2. The idea is to heat the battery while you drive to the charger so it can accept charge at a higher rate. You must select a DC charger in the Ford Nav and be within 30 km (19 mi) of it before preconditioning will occur.

To set the stage here, it's a below 0ÂșF day here. I Level 2 charged all day at work, and even though I was charging the battery still cooled off to -8ÂșC (18ÂșF) by quitting time. I input the local EA station into the nav, and I heard the battery heating start. However it shut off shortly after taking off. Because it's so cold, the cabin heater was taking too much power and preconditioning was cancelled. Bummer. Until I had the bright idea of turning OFF HVAC. Well, that worked, fired the battery heating right up.

Now a normal person probably would have called it quits after a few minutes of no cabin heat in these pleasant -19ÂșC (-2ÂșF) temps, but I'm not normal. Yes, I suffered for science đŸ„¶ in order to see how long it would take to heat the battery up for DCFC, and how high it would go. The short answer is it took AN HOUR AT FULL HEATER OUTPUT to reach the 26ÂșC target temp for DCFC. An hour seems much longer when you're freezing. To get around the 30 km geofence limitation, I drove in circles on the highways surrounding the charger. I could have parked it and went inside, but I wanted the airflow under the pack to simulate real-world cooling effects on a highway. BTW, to avoid the windows fogging up, you need some air movement, so I ended up setting the cabin temp on LO with the fan on speed 1. That disables cabin heat and blows raw outside air at you. That helped make a pretty graph that wasn't disrupted by repeated defrost cycles, and it also helped the cabin cool down to 15ÂșF while I was driving. I was very happy to see the heater finally shut off, and immediately switched the cabin heat back on as I made my way to the EA station for DCFC.

So let's take a look at the temperature graph:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Preconditioned DCFC Sessio


Focus on the blue line which is the main pack temp. In 61 minutes it went from -8ÂșC (18ÂșF) to 26ÂșC (79ÂșF). The heater output started at 6.2 kW and gradually declined to 5.6 kW (this is the PTC effect as the coolant return temp increases). Keep in mind this graph really represents the fastest you could possibly heat the battery in these conditions, the amount of heat available with the HVAC on simultaneously will be quite a bit less. If the HVAC was on at the same time, pack heating likely would have taken two hours and would have run into a wall before reaching 26ÂșC. Perhaps it would have only reached 5ÂșC. This is why it was disabled due to limited heat reserve. I will need to wait for a warmer day to test battery preconditioning while the cabin heat is still active, but the rate of heating will be significantly less.

Now let's look at the DCFC session at a 150 kW EA station I reached shortly after battery heating finished:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Preconditioned DCFC Sessio


Temp was down to about -20ÂșC/-4ÂșF when I pulled in. A lot of the chargers were displaying a "power reduced" message. I chose one not displaying the message, and activated with Plug & Charge. However I immediately noticed a 196A max current limitation (blue line), much less than the 350A these stations should be capable of. I wasn't happy with only 62 kW, so I decided to try a different dispenser. This one allowed up to 236A which was an improvement, but still slower than it should be. Not sure how much the cold affects these things. The car was correctly asking for full amperage (red line) at first, but the stations always supply (green line) 10-20 amps less than requested for some reason.

After reaching about 59%, the car decided to start requesting less current from the charger, you can see the red request line start decreasing. This is frustrating because the battery is warm enough and perfectly capable of handling the full 236A all the way up to at least 75-80% SoC. Ford has this weird charging strategy where they set the reminder of the charge curve based on the initial rate. Almost like it's a percentage of the initial rate. This means if you use a slower charging station, it will slow you down that much more for the rest of the curve based on the initial speed. This is totally not necessary, there should be a calculated maximum rate at each % SoC based on the battery temps. When using a slower DCFC station (<80 kW), it should be pegged at maximum output the whole way to 75-80%. At only 218A, no part of the battery should be getting that hot so I just don't see the need to throttle it. Ford should work on this strategy because they are needlessly reducing the charging speeds at lower power DCFC stations.

During the DCFC session, the battery was not heated any more by the PTC heater. I shut HVAC off to make sure, nothing happened. I've seen some cases where it heats more than 26ÂșC after starting a session, the decision to heat more must be tied to the charging power available. In this case heating more wasn't necessary for the speeds I was charging at. Temp increased from 23ÂșC to 26ÂșC on its own during the session (yellow trace at the top).

Findings:
  • Battery took 1 hour to heat from -8ÂșC to 26ÂșC using full 6 kW heater output (34ÂșC/hr)
  • Battery heat capacity is 0.18 kWh/ÂșC or 630 kJ/ÂșC
  • Preconditioning starts as soon as a DC station within 30 km is selected in the Ford nav
  • There is no time limit on battery heating as long as you remain within 30 km of the station
  • There is a 26ÂșC upper temp limit
  • En-route preconditioning will not occur at extreme cold temps unless you turn off HVAC
  • Many EA stations operate with significantly degraded performance
  • EA stations output 10-20 amps less than requested by the car
  • Additional heating above 26ÂșC while DCFCing is not always commanded
  • Ford throttles back the charge rate unnecessarily at lower-amperage DC stations
Conclusions:
  • The Mach-E needs a dedicated 5 kW battery heater that is not shared with the cabin.
  • Battery temp increase will be limited with only a 30 km range limit.
    • I think this limit should be increased to 60-120 km to give enough time.
  • EA stations are in varying states of disrepair
  • Ford should fix unnecessary throttling of low-amp DC stations and allow full current up to 75-80%. The current limit at 50-75% should not be affected by the initial station amperage unless using a high amperage (300+) station.
Thank you for your service and sacrifice. Hopefully no fingers or toes were lost in the process
 


breeves002

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  • Ford should fix unnecessary throttling of low-amp DC stations and allow full current up to 75-80%. The current limit at 50-75% should not be affected by the initial station amperage unless using a high amperage (300+) station.
First of all you're crazy screw that cold.

Second, YES TO THIS POINT! PLEASE FIX THIS! It is SO FRUSTRATING when I charge at my 50kW charger and it starts throttling for no reason!!!!!! At an EA station outputting full power I get 43kW at 80% but at a 50kW station I get 25kW at 80%. It makes no sense!

Please Ford fix this and save me HOURS of my life.
 
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To go with the above post, I wanted to add this chart that provides the amount of time it would take to heat up the battery from various starting temps and input heat:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] DCFC Heating Time

Based on +38ÂșC/hr rate

Those times are hours and minutes, not minutes and seconds. Keep in mind that while using cabin heat (which shares the same heater), the amount of heat available for pack heating will be limited to around 1-4 kW depending on the outside temp (less when colder). For example, if the pack starts at 5ÂșC and you only have 2 kW of extra heat available, it will take 1 hour 39 minutes for it to warm up to DCFC temp while driving.

Now let's consider if you're driving 75 MPH / 121 kph on the interstate towards a DC fast station. The heating activates at only 30 km out. If you do the math, it will only run for about 15 minutes at interstate speed. Now look at that table and see in how many scenarios will the heating require less than 0:15? This is why the Mach-E needs a dedicated battery heater (so it runs in the last column), and why 30 km is peanuts in terms of time. The median time in this chart is 75 minutes. If we wanted the battery to heat that long, a range threshold of 150 km should be used. If the battery has been recently DC fast charged at a previous stop, perhaps it's cooled down to 15ÂșC and starting at around 80 km would be needed. It almost always requires a lot longer than 30 km to heat. Because of the large differences in times, the range threshold needs to be set intelligently based on the battery temp. I know this first version of en-route preconditioning was probably somewhat makeshift to introduce the feature, but hopefully we get something more efficacious by next winter.
 
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Pretty Sweet that Ford is giving these upgrades.
 

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To go with the above post, I wanted to add this chart that provides the amount of time it would take to heat up the battery from various starting temps and input heat:

DCFC Heating Time.png

Based on +38ÂșC/hr rate
Thanks for this!

I'm pretty impressed that Ford can keep the battery on a nearly linear 38ÂșC/hr warming rate for so long. For non-forced radiative cooling the cooling rate of a warm object at temperature T (in Kelvins) radiating to an environment T0 is dependent on (T-T0)^4. For forced cooling (i.e., wind blowing across the object), there's this radiative component as well as an additional forced component.
 

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En-Route Battery Preconditioning for DCFC

Today's test is the new en-route battery preconditioning feature introduced in Power-Up 3.6.2. The idea is to heat the battery while you drive to the charger so it can accept charge at a higher rate. You must select a DC charger in the Ford Nav and be within 30 km (19 mi) of it before preconditioning will occur.

To set the stage here, it's a below 0ÂșF day here. I Level 2 charged all day at work, and even though I was charging the battery still cooled off to -8ÂșC (18ÂșF) by quitting time. I input the local EA station into the nav, and I heard the battery heating start. However it shut off shortly after taking off. Because it's so cold, the cabin heater was taking too much power and preconditioning was cancelled. Bummer. Until I had the bright idea of turning OFF HVAC. Well, that worked, fired the battery heating right up.

Now a normal person probably would have called it quits after a few minutes of no cabin heat in these pleasant -19ÂșC (-2ÂșF) temps, but I'm not normal. Yes, I suffered for science đŸ„¶ in order to see how long it would take to heat the battery up for DCFC, and how high it would go. The short answer is it took AN HOUR AT FULL HEATER OUTPUT to reach the 26ÂșC target temp for DCFC. An hour seems much longer when you're freezing. To get around the 30 km geofence limitation, I drove in circles on the highways surrounding the charger. I could have parked it and went inside, but I wanted the airflow under the pack to simulate real-world cooling effects on a highway. BTW, to avoid the windows fogging up, you need some air movement, so I ended up setting the cabin temp on LO with the fan on speed 1. That disables cabin heat and blows raw outside air at you. That helped make a pretty graph that wasn't disrupted by repeated defrost cycles, and it also helped the cabin cool down to 15ÂșF while I was driving. I was very happy to see the heater finally shut off, and immediately switched the cabin heat back on as I made my way to the EA station for DCFC.

So let's take a look at the temperature graph:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] DCFC Heating Time


Focus on the blue line which is the main pack temp. In 61 minutes it went from -8ÂșC (18ÂșF) to 26ÂșC (79ÂșF). The heater output started at 6.2 kW and gradually declined to 5.6 kW (this is the PTC effect as the coolant return temp increases). Keep in mind this graph really represents the fastest you could possibly heat the battery in these conditions, the amount of heat available with the HVAC on simultaneously will be quite a bit less. If the HVAC was on at the same time, pack heating likely would have taken two hours and would have run into a wall before reaching 26ÂșC. Perhaps it would have only reached 5ÂșC. This is why it was disabled due to limited heat reserve. I will need to wait for a warmer day to test battery preconditioning while the cabin heat is still active, but the rate of heating will be significantly less.

Now let's look at the DCFC session at a 150 kW EA station I reached shortly after battery heating finished:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] DCFC Heating Time


Temp was down to about -20ÂșC/-4ÂșF when I pulled in. A lot of the chargers were displaying a "power reduced" message. I chose one not displaying the message, and activated with Plug & Charge. However I immediately noticed a 196A max current limitation (blue line), much less than the 350A these stations should be capable of. I wasn't happy with only 62 kW, so I decided to try a different dispenser. This one allowed up to 236A which was an improvement, but still slower than it should be. Not sure how much the cold affects these things. The car was correctly asking for full amperage (red line) at first, but the stations always supply (green line) 10-20 amps less than requested for some reason.

After reaching about 59%, the car decided to start requesting less current from the charger, you can see the red request line start decreasing. This is frustrating because the battery is warm enough and perfectly capable of handling the full 236A all the way up to at least 75-80% SoC. Ford has this weird charging strategy where they set the remainder of the charge curve based on the initial rate. Almost like it's a percentage of the initial rate. This means if you use a slower charging station, it will slow you down that much more for the rest of the curve based on the initial speed. This is totally not necessary, there should be a calculated maximum rate at each % SoC based on the battery temps. When using a slower DCFC station (<80 kW), it should be pegged at maximum output the whole way to 75-80%. At only 218A, no part of the battery should be getting that hot so I just don't see the need to throttle it. Ford should work on this strategy because they are needlessly reducing the charging speeds at lower power DCFC stations.

During the DCFC session, the battery was not heated any more by the PTC heater. I shut HVAC off to make sure, nothing happened. I've seen some cases where it heats more than 26ÂșC after starting a session, the decision to heat more must be tied to the charging power available. In this case heating more wasn't necessary for the speeds I was charging at. Temp increased from 23ÂșC to 26ÂșC on its own during the session (yellow trace at the top).

Findings:
  • Battery took 1 hour to heat from -8ÂșC to 26ÂșC using full 6 kW heater output (34ÂșC/hr)
  • Battery heat capacity is 0.18 kWh/ÂșC or 630 kJ/ÂșC
  • Preconditioning starts as soon as a DC station within 30 km is selected in the Ford nav
  • There is no time limit on battery heating as long as you remain within 30 km of the station
  • There is a 26ÂșC upper temp limit
  • En-route preconditioning will not occur at extreme cold temps unless you turn off HVAC
  • Many EA stations operate with significantly degraded performance
  • EA stations output 10-20 amps less than requested by the car
  • Additional heating above 26ÂșC while DCFCing is not always commanded
  • Ford throttles back the charge rate unnecessarily at lower-amperage DC stations
Conclusions:
  • The Mach-E needs a dedicated 5 kW battery heater that is not shared with the cabin.
  • Battery temp increase will be limited with only a 30 km range limit.
    • I think this limit should be increased to 60-120 km to give enough time.
  • EA stations are in varying states of disrepair
  • Ford should fix unnecessary throttling of low-amp DC stations and allow full current up to 75-80%. The current limit at 50-75% should not be affected by the initial station amperage unless using a high amperage (300+) station.
We’re you looking at the min and max battery temps in car scanner? I am curious if the min was 26 because the max was higher. When I tested preconditioning on my Mach-e (on a much warmer day of 5 degree Celsius ) the inter temp was over 40c and the battery max temp was mid-30’s and I believe the average was 30-31C
 
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Mach-Lee

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We’re you looking at the min and max battery temps in car scanner? I am curious if the min was 26 because the max was higher. When I tested preconditioning on my Mach-e (on a much warmer day of 5 degree Celsius ) the inter temp was over 40c and the battery max temp was mid-30’s and I believe the average was 30-31C
Yup, they're on the graph there. Min is dark red, max is yellow. I go by the main pack temp for discussion because most of the cells are closest to that. The cells on the bottom are the coldest, the cells on the top stack under the rear seat get some heat from the cabin and are warmest as heat rises inside the pack.

At the end of Preconditioning:
Min: 14ÂșC, Max: 30ÂșC, Average: 26ÂșC
 
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Reflectix Panoramic Roof Insulation Test

Due to issues with not enough heat in cold temps, I decided to test the effect of covering the panoramic roof with a sheet of Reflectix, which is commonly used by vanlife people to cover their windows while sleeping. This product is essentially bubble wrap with Mylar added to provide a radiant barrier. It reflects heat, hence its name. Here's how to make this.

Before the test, I decided to do some quick calculations to see how big the effect might be. The Mach-E panoramic roof is tinted darkly and has a UV coating, but it is not infrared reflective (IRR) like the windshield is. A standard piece of single pane glass has a U-value of about 1.5, which translates to an R-value of 0.66. Reflectix in this application has a R-value of 3.0 (U-value 0.33). The glass roof is about 11 square feet. Let's calculate the heat loss with 70ÂșF inside and -15ÂșF outside (85ÂșF differential):

Glass only: 1/0.66 x 11 x 85 = 1400 BTU/hr
Glass + Reflectix: 1/(0.66+3.0) x 11 x 85 = 255 BTU/hr

So that's 1145 BTU/hr improvement in heat loss, or about 335W of extra heat. But that's while stationary. In motion, the wind creates huge convective "wind chill" effect that dramatically increases the heat loss, so the insulation may be even more effective. Let's test it.

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflectix Roof


1/31 Trip Summary:

Outdoor temp: -15ÂșF/-26ÂșC
Wind: S 3 mph
Trip distance: 89.3 mi
Duration: 82 min
Displayed efficiency: 1.8 mi/kWh
Average speed: 65 MPH

Starting conditions:
Cabin temp: 66.6ÂșF
Battery temp: 57.2ÂșF
Displayed SoC: 79.0%
Displayed Range: 214 mi
kWh to empty: 64.84

Ending conditions:
Cabin temp: 60.3ÂșF
Battery temp: 32.0ÂșF
Displayed SoC: 18.0%
Displayed Range: 24 mi
kWh to empty: 13.56

Calculated stats:
Battery used: 61.0%
Energy used (BECM): 51.28 kWh
Calculated efficiency: 1.74 mi/kWh (based on above)
Calculated efficiency: 1.79 (based on wall)
100% range at -15ÂșF: 146 miles (53% of EPA)
100% energy available: 84.1 kWh

Charge back energy:
54.4 kWh from wall
91.5 % charging efficiency
49.8 kWh estimated to the pack

I took my usual 89.3 mi route, out and back (highway and 75 MPH on the interstate). At the halfway point where I turned around (magenta line on graphs), I removed the Reflectix and watched the effect on cabin temps. So first half of the test is with Reflectix, second half is without. First let's look at exterior temps:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Exterior Tem


The local weather stations were reporting about -15ÂșF at the time, so I think the sensor in the Mach-E for that data might be a little warmer than reality. I found it interesting you can see the symmetrical pattern of dips (yellow arrows) which are the valleys I drove through, they collect the sinking cold air and can be dramatically colder, and you can feel it. Takeaway message is the exterior temps were extremely similar during both halves of the trip. Now let's look at cabin temps:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflectix Cabin Tem


HVAC set to 68ÂșF AUTO 2. This temp sensor was on the passenger seat at about chest height. During the first half, I felt mostly warm and comfortable. No draft under the seat. Vent temps were about 85ÂșF. Only when I was in the valley with -20ÂșF temps near the turnaround did I start to feel like I was getting too cold.

While turning around, I pulled the Reflectix down. IMMEDIATE COLD DRAFT on my head. In less than 5 minutes, my ankles and legs started to get uncomfortably cold due to the cold air pooling at the floor. There was now a cold draft coming from under the seat. Vent temps dropped about 15Âș to 70ÂșF. I was also monitoring the surface temp of a blanket (low thermal mass radiative telltale) on my front seat with my infrared temp gun. Before it was about 64ÂșF, after the Reflectix was removed I saw the blanket reading get down to 46ÂșF! It probably had a cold draft falling on it just like my head. In the graph above, you can see the immediate drop in temp right after removing, and the overall cooling trend during the second half. It wasn't until I got off the interstate and slowed down did the cabin temp start to recover some at the end. The dips in the graph are when the HVAC strategy closed off the fresh air, that changes the airflow pattern such the sensor actually got colder. The windows also fogged up some during those dips.

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Interior Tem


This was the interior temp sensor above the rear mirror. This one registers about a 8ÂșF temp drop after Reflectix removal.

So my subjective view is putting in the Reflectix make a HUGE DIFFERENCE in comfort at these temps. Depending on the metric, I saw a 6-10ÂșF drop in average cabin temps. It honestly felt worse than that though. The drafts created by the cold glass overhead changed the temperature distribution in the cabin dramatically and created cold spots. If I would have put a temp sensor near the floor, I'm guessing it would have registered a 20ÂșF drop or more like the blanket did. Last, let's look at the battery temps like usual:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


Looking at the inlet temp, the battery was being HEATED for most of the trip. It still cooled off though, the heater just slowed down the loss and arrested the battery temp right at 0ÂșC. Overall, the battery went from 14ÂșC to 0ÂșC. Because the of the extreme cold, the cabin is taking most of the heat. The battery is probably only getting about a 1 kW or less of heat, just enough to keep it around freezing.

Let's circle back to the heat loss difference and summarize. Without the Reflectix, the cabin can only maintain a maximum differential of about +72ÂșF/+40ÂșC (data from this and previous tests). Which means at -15ÂșF the warmest the cabin will get is about 57ÂșF. With the Reflectix, the differential increased to +81ÂșF/45ÂșC, so at -15ÂșF the cabin temp will be about 66ÂșF. That's about a 13% improvement in heat output, and means your car will stay warmer down to a temperature that's 10ÂșF/5ÂșC colder. If we assume the cabin was being heated with about 4.5 kW of heat (leaving some for the battery), a 13% improvement would be about 550W. That's about double what I predicted because of the wind effect taking away more heat.

So there you have it, covering the roof glass with Reflectix is like adding a 550W heater to the cabin when it's this cold. It makes a noticeable difference. It also makes the car slightly more efficient.

If you live in northern states or Canada, I recommend NOT getting the panoramic roof because of the additional heat loss. I wish Ford would have made it an option on more vehicles rather than being included with most trims so we could opt-out. I wouldn't have gotten it. Or at least included a fricking shade to cover it in the winter! In all my other cars the sunroof shade stays closed in the winter.

Findings:
  • Reflectix made the cabin temps 6-10ÂșF (3-5ÂșC) warmer at -15ÂșF/-26ÂșC
  • Cabin subjectively felt much more comfortable and much less drafty
  • Cabin temperature differential (∆T) increased from +72ÂșF (+40ÂșC) to +81ÂșF (+45ÂșC)
  • Reflectix saves up to 600W of heat loss (depends on temp and speed)
  • Battery was being heated to maintain temperature during the drive
  • Battery temp dropped from 14ÂșC to 0ÂșC during the 82 minute drive
  • Battery temp leveled off at 0ÂșC (thermal equilibrium)
Conclusions:
  • The Reflectix made a huge improvement in comfort, more than I expected
  • This will allow my Mach-E to stay comfortable down to about -16ÂșF/-27ÂșC
  • The glass roof presents a significant heat loss in cold climates
    • The glass coatings are optimized to reduce solar heat gain, not prevent heat loss
  • The heater needs to be bigger on glass roof cars so this isn't necessary
  • A cover shade should have been provided despite the weight savings
  • Glass roof should be optional in Canada and northern states, avoid if possible
  • Not enough heat was available to keep the battery warm (e.g. 5ÂșC)
    • A separate heater for the battery pack is really necessary
  • Ford's latest powertrain software does a better job keeping the battery warm, to the highest extent possible given the heater design limitations

WARNING: DO NOT LEAVE Reflextix in the window, remove in early March before the sun gets strong to avoid damaging the glass. WINTER USE ONLY. It is not necessary in the summer.
 
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awp0

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This thread is fascinating, and thank you for the testing and data!

Question: I think I understand that the MME won't precondition (with "scheduled departure") if it's connected to Level 1 charging. But when it's sitting overnight on L1 charging and the temps drop to extreme levels, will it try to warm the battery to protect it? Does it need to?

Background: I'm planning to drive 130 miles in my MME Prem AWD ER this afternoon with a starting temp of 0F and arrival temp of -16F. I will fully charge and precondition on L2 at home, and then hope for the best. But then it'll sit in a driveway, possibly only with L1 charging, overnight with temps dropping to -20F. Should I worry about that? (I will have access to L2 to get a charge for the drive back home, but I'll be competing with my friend, a Tesla owner, to use it and so I'm not sure I'll have it overnight)

Edit: we changed our plans and decided to stay home tonight. I probably don't need the L1 battery warming question answered (hopefully ever!)
 
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mkhuffman

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Reflectix Panoramic Roof Insulation Test

Due to issues with not enough heat in cold temps, I decided to test the effect of covering the panoramic roof with a sheet of Reflectix, which is commonly used by vanlife people to cover their windows while sleeping. This product is essentially bubble wrap with Mylar added to provide a radiant barrier. It reflects heat, hence its name. I will discuss how I made the sheet in another topic soon.

Before the test, I decided to do some quick calculations to see how big the effect might be. The Mach-E panoramic roof is tinted darkly and has a UV coating, but it is not infrared reflective (IRR) like the windshield is. A standard piece of single pane glass has a U-value of about 1.5, which translates to an R-value of 0.66. Reflectix in this application has a R-value of 3.0 (U-value 0.33). The glass roof is about 11 square feet. Let's calculate the heat loss with 70ÂșF inside and -15ÂșF outside (85ÂșF differential):

Glass only: 1/0.66 x 11 x 85 = 1400 BTU/hr
Glass + Reflectix: 1/(0.66+3.0) x 11 x 85 = 255 BTU/hr

So that's 1145 BTU/hr improvement in heat loss, or about 335W of extra heat. But that's while stationary. In motion, the wind creates huge convective "wind chill" effect that dramatically increases the heat loss, so the insulation may be even more effective. Let's test it.

Reflectix Roof.jpg


1/31 Trip Summary:

Outdoor temp: -15ÂșF/-26ÂșC
Wind: S 3 mph
Trip distance: 89.3 mi
Duration: 82 min
Displayed efficiency: 1.8 mi/kWh
Average speed: 65 MPH

Starting conditions:
Cabin temp: 66.6ÂșF
Battery temp: 57.2ÂșF
Displayed SoC: 79.0%
Displayed Range: 214 mi
kWh to empty: 64.84

Ending conditions:
Cabin temp: 60.3ÂșF
Battery temp: 32.0ÂșF
Displayed SoC: 18.0%
Displayed Range: 24 mi
kWh to empty: 13.56

Calculated stats:
Battery used: 61.0%
Energy used (BECM): 51.28 kWh
Calculated efficiency: 1.74 mi/kWh (based on above)
Calculated efficiency: 1.79 (based on wall)
100% range at -15ÂșF: 146 miles (53% of EPA)
100% energy available: 84.1 kWh

Charge back energy:
54.4 kWh from wall
91.5 % charging efficiency
49.8 kWh estimated to the pack

I took my usual 89.3 mi route, out and back (highway and 75 MPH on the interstate). At the halfway point where I turned around (magenta line on graphs), I removed the Reflectix and watched the effect on cabin temps. So first half of the test is with Reflectix, second half is without. First let's look at exterior temps:

Exterior Temp.png


The local weather stations were reporting about -15ÂșF at the time, so I think the sensor in the Mach-E for that data might be a little warmer than reality. I found it interesting you can see the symmetrical pattern of dips (yellow arrows) which are the valleys I drove through, they collect the sinking cold air and can be dramatically colder, and you can feel it. Takeaway message is the exterior temps were extremely similar during both halves of the trip. Now let's look at cabin temps:

Reflectix Cabin Temp.png


HVAC set to 68ÂșF AUTO 2. This temp sensor was on the passenger seat at about chest height. During the first half, I felt mostly warm and comfortable. No draft under the seat. Vent temps were about 85ÂșF. Only when I was in the valley with -20ÂșF temps near the turnaround did I start to feel like I was getting too cold.

While turning around, I pulled the Reflectix down. IMMEDIATE COLD DRAFT on my head. In less than 5 minutes, my ankles and legs started to get uncomfortably cold due to the cold air pooling at the floor. There was now a cold draft coming from under the seat. Vent temps dropped about 15Âș to 70ÂșF. I was also monitoring the surface temp of a blanket (low thermal mass radiative telltale) on my front seat with my infrared temp gun. Before it was about 64ÂșF, after the Reflectix was removed I saw the blanket reading get down to 46ÂșF! It probably had a cold draft falling on it just like my head. In the graph above, you can see the immediate drop in temp right after removing, and the overall cooling trend during the second half. It wasn't until I got off the interstate and slowed down did the cabin temp start to recover some at the end. The dips in the graph are when the HVAC strategy closed off the fresh air, that changes the airflow pattern such the sensor actually got colder. The windows also fogged up some during those dips.

Interior Temp.png


This was the interior temp sensor above the rear mirror. This one registers about a 8ÂșF temp drop after Reflectix removal.

So my subjective view is putting in the Reflectix make a HUGE DIFFERENCE in comfort at these temps. Depending on the metric, I saw a 6-10ÂșF drop in average cabin temps. It honestly felt worse than that though. The drafts created by the cold glass overhead changed the temperature distribution in the cabin dramatically and created cold spots. If I would have put a temp sensor near the floor, I'm guessing it would have registered a 20ÂșF drop or more like the blanket did. Last, let's look at the battery temps like usual:

Reflextix Battery Temps.png


Looking at the inlet temp, the battery was being HEATED for most of the trip. It still cooled off though, the heater just slowed down the loss and arrested the battery temp right at 0ÂșC. Overall, the battery went from 14ÂșC to 0ÂșC. Because the of the extreme cold, the cabin is taking most of the heat. The battery is probably only getting about a 1 kW or less of heat, just enough to keep it around freezing.

Let's circle back to the heat loss difference and summarize. Without the Reflectix, the cabin can only maintain a maximum differential of about +72ÂșF/+40ÂșC (data from this and previous tests). Which means at -15ÂșF the warmest the cabin will get is about 57ÂșF. With the Reflectix, the differential increased to +81ÂșF/45ÂșC, so at -15ÂșF the cabin temp will be about 66ÂșF. That's about a 13% improvement in heat output, and means your car will stay warmer down to a temperature that's 10ÂșF/5ÂșC colder. If we assume the cabin was being heated with about 4.5 kW of heat (leaving some for the battery), a 13% improvement would be about 550W. That's about double what I predicted because of the wind effect taking away more heat.

So there you have it, covering the roof glass with Reflectix is like adding a 550W heater to the cabin when it's this cold. It makes a noticeable difference. It also makes the car slightly more efficient.

If you live in northern states or Canada, I recommend NOT getting the panoramic roof because of the additional heat loss. I wish Ford would have made it an option on more vehicles rather than being included with most trims so we could opt-out. I wouldn't have gotten it. Or at least included a fricking shade to cover it in the winter! In all my other cars the sunroof shade stays closed in the winter.

Findings:
  • Reflectix made the cabin temps 6-10ÂșF (3-5ÂșC) warmer at -15ÂșF/-26ÂșC
  • Cabin subjectively felt much more comfortable and much less drafty
  • Cabin temperature differential (∆T) increased from +72ÂșF (+40ÂșC) to +81ÂșF (+45ÂșC)
  • Reflectix saves up to 600W of heat loss (depends on temp and speed)
  • Battery was being heated to maintain temperature during the drive
  • Battery temp dropped from 14ÂșC to 0ÂșC during the 82 minute drive
  • Battery temp leveled off at 0ÂșC (thermal equilibrium)
Conclusions:
  • The Reflectix made a huge improvement in comfort, more than I expected
  • This will allow my Mach-E to stay comfortable down to about -16ÂșF/-27ÂșC
  • The glass roof presents a significant heat loss in cold climates
    • The glass coatings are optimized to reduce solar heat gain, not prevent heat loss
  • The heater needs to be bigger on glass roof cars so this isn't necessary
  • A cover shade should have been provided despite the weight savings
  • Glass roof should be optional in Canada and northern states, avoid if possible
  • Not enough heat was available to keep the battery warm (e.g. 5ÂșC)
    • A separate heater for the battery pack is really necessary
  • Ford's latest powertrain software does a better job keeping the battery warm, to the highest extent possible given the heater design limitations

WARNING: DO NOT LEAVE Reflextix in the window, remove in early March before the sun gets strong to avoid damaging the glass. WINTER USE ONLY. It is not necessary in the summer.
I suspect my metal roof is even better than the Reflectix in the cold, but I would need two MMEs to test that. Your testing does confirm what I have suspected all along, and explains why I can drive a long distance until I have to turn the cabin heat on when it is cold outside. The metal roof appears to be well insulated. Glass is not unless it is double pane with argon gas, something like a house window. But of course even those are colder than an insulated wall.

Another insightful post! Thanks Lee!
 
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21st Century Pony

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Reflectix Panoramic Roof Insulation Test

Due to issues with not enough heat in cold temps, I decided to test the effect of covering the panoramic roof with a sheet of Reflectix, which is commonly used by vanlife people to cover their windows while sleeping. This product is essentially bubble wrap with Mylar added to provide a radiant barrier. It reflects heat, hence its name. I will discuss how I made the sheet in another topic soon.

Before the test, I decided to do some quick calculations to see how big the effect might be. The Mach-E panoramic roof is tinted darkly and has a UV coating, but it is not infrared reflective (IRR) like the windshield is. A standard piece of single pane glass has a U-value of about 1.5, which translates to an R-value of 0.66. Reflectix in this application has a R-value of 3.0 (U-value 0.33). The glass roof is about 11 square feet. Let's calculate the heat loss with 70ÂșF inside and -15ÂșF outside (85ÂșF differential):

Glass only: 1/0.66 x 11 x 85 = 1400 BTU/hr
Glass + Reflectix: 1/(0.66+3.0) x 11 x 85 = 255 BTU/hr

So that's 1145 BTU/hr improvement in heat loss, or about 335W of extra heat. But that's while stationary. In motion, the wind creates huge convective "wind chill" effect that dramatically increases the heat loss, so the insulation may be even more effective. Let's test it.

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


1/31 Trip Summary:

Outdoor temp: -15ÂșF/-26ÂșC
Wind: S 3 mph
Trip distance: 89.3 mi
Duration: 82 min
Displayed efficiency: 1.8 mi/kWh
Average speed: 65 MPH

Starting conditions:
Cabin temp: 66.6ÂșF
Battery temp: 57.2ÂșF
Displayed SoC: 79.0%
Displayed Range: 214 mi
kWh to empty: 64.84

Ending conditions:
Cabin temp: 60.3ÂșF
Battery temp: 32.0ÂșF
Displayed SoC: 18.0%
Displayed Range: 24 mi
kWh to empty: 13.56

Calculated stats:
Battery used: 61.0%
Energy used (BECM): 51.28 kWh
Calculated efficiency: 1.74 mi/kWh (based on above)
Calculated efficiency: 1.79 (based on wall)
100% range at -15ÂșF: 146 miles (53% of EPA)
100% energy available: 84.1 kWh

Charge back energy:
54.4 kWh from wall
91.5 % charging efficiency
49.8 kWh estimated to the pack

I took my usual 89.3 mi route, out and back (highway and 75 MPH on the interstate). At the halfway point where I turned around (magenta line on graphs), I removed the Reflectix and watched the effect on cabin temps. So first half of the test is with Reflectix, second half is without. First let's look at exterior temps:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


The local weather stations were reporting about -15ÂșF at the time, so I think the sensor in the Mach-E for that data might be a little warmer than reality. I found it interesting you can see the symmetrical pattern of dips (yellow arrows) which are the valleys I drove through, they collect the sinking cold air and can be dramatically colder, and you can feel it. Takeaway message is the exterior temps were extremely similar during both halves of the trip. Now let's look at cabin temps:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


HVAC set to 68ÂșF AUTO 2. This temp sensor was on the passenger seat at about chest height. During the first half, I felt mostly warm and comfortable. No draft under the seat. Vent temps were about 85ÂșF. Only when I was in the valley with -20ÂșF temps near the turnaround did I start to feel like I was getting too cold.

While turning around, I pulled the Reflectix down. IMMEDIATE COLD DRAFT on my head. In less than 5 minutes, my ankles and legs started to get uncomfortably cold due to the cold air pooling at the floor. There was now a cold draft coming from under the seat. Vent temps dropped about 15Âș to 70ÂșF. I was also monitoring the surface temp of a blanket (low thermal mass radiative telltale) on my front seat with my infrared temp gun. Before it was about 64ÂșF, after the Reflectix was removed I saw the blanket reading get down to 46ÂșF! It probably had a cold draft falling on it just like my head. In the graph above, you can see the immediate drop in temp right after removing, and the overall cooling trend during the second half. It wasn't until I got off the interstate and slowed down did the cabin temp start to recover some at the end. The dips in the graph are when the HVAC strategy closed off the fresh air, that changes the airflow pattern such the sensor actually got colder. The windows also fogged up some during those dips.

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


This was the interior temp sensor above the rear mirror. This one registers about a 8ÂșF temp drop after Reflectix removal.

So my subjective view is putting in the Reflectix make a HUGE DIFFERENCE in comfort at these temps. Depending on the metric, I saw a 6-10ÂșF drop in average cabin temps. It honestly felt worse than that though. The drafts created by the cold glass overhead changed the temperature distribution in the cabin dramatically and created cold spots. If I would have put a temp sensor near the floor, I'm guessing it would have registered a 20ÂșF drop or more like the blanket did. Last, let's look at the battery temps like usual:

Ford Mustang Mach-E Mach-Lee's Mach-E Cold Weather Testing [Taking Requests] Reflextix Battery Temps


Looking at the inlet temp, the battery was being HEATED for most of the trip. It still cooled off though, the heater just slowed down the loss and arrested the battery temp right at 0ÂșC. Overall, the battery went from 14ÂșC to 0ÂșC. Because the of the extreme cold, the cabin is taking most of the heat. The battery is probably only getting about a 1 kW or less of heat, just enough to keep it around freezing.

Let's circle back to the heat loss difference and summarize. Without the Reflectix, the cabin can only maintain a maximum differential of about +72ÂșF/+40ÂșC (data from this and previous tests). Which means at -15ÂșF the warmest the cabin will get is about 57ÂșF. With the Reflectix, the differential increased to +81ÂșF/45ÂșC, so at -15ÂșF the cabin temp will be about 66ÂșF. That's about a 13% improvement in heat output, and means your car will stay warmer down to a temperature that's 10ÂșF/5ÂșC colder. If we assume the cabin was being heated with about 4.5 kW of heat (leaving some for the battery), a 13% improvement would be about 550W. That's about double what I predicted because of the wind effect taking away more heat.

So there you have it, covering the roof glass with Reflectix is like adding a 550W heater to the cabin when it's this cold. It makes a noticeable difference. It also makes the car slightly more efficient.

If you live in northern states or Canada, I recommend NOT getting the panoramic roof because of the additional heat loss. I wish Ford would have made it an option on more vehicles rather than being included with most trims so we could opt-out. I wouldn't have gotten it. Or at least included a fricking shade to cover it in the winter! In all my other cars the sunroof shade stays closed in the winter.

Findings:
  • Reflectix made the cabin temps 6-10ÂșF (3-5ÂșC) warmer at -15ÂșF/-26ÂșC
  • Cabin subjectively felt much more comfortable and much less drafty
  • Cabin temperature differential (∆T) increased from +72ÂșF (+40ÂșC) to +81ÂșF (+45ÂșC)
  • Reflectix saves up to 600W of heat loss (depends on temp and speed)
  • Battery was being heated to maintain temperature during the drive
  • Battery temp dropped from 14ÂșC to 0ÂșC during the 82 minute drive
  • Battery temp leveled off at 0ÂșC (thermal equilibrium)
Conclusions:
  • The Reflectix made a huge improvement in comfort, more than I expected
  • This will allow my Mach-E to stay comfortable down to about -16ÂșF/-27ÂșC
  • The glass roof presents a significant heat loss in cold climates
    • The glass coatings are optimized to reduce solar heat gain, not prevent heat loss
  • The heater needs to be bigger on glass roof cars so this isn't necessary
  • A cover shade should have been provided despite the weight savings
  • Glass roof should be optional in Canada and northern states, avoid if possible
  • Not enough heat was available to keep the battery warm (e.g. 5ÂșC)
    • A separate heater for the battery pack is really necessary
  • Ford's latest powertrain software does a better job keeping the battery warm, to the highest extent possible given the heater design limitations

WARNING: DO NOT LEAVE Reflextix in the window, remove in early March before the sun gets strong to avoid damaging the glass. WINTER USE ONLY. It is not necessary in the summer.
Now I wonder whether the Summer black mesh aftermarket pano roof insert, along with its top reflective layer, makes any heater use difference in very cold temperatures.
 
 




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