PSA: Keep The Battery Warm So You Have Enough Cabin Heat

[Mach-Lee]

Wanted to write a note about this since many people are currently experiencing extreme cold temps (below 5ºF/-15ºC). In a nutshell:

Keeping the battery is warm is important so you have enough cabin heat!

If the battery is cold, the Mach-E will steal your cabin heat to warm the battery. The heater is shared between the battery and cabin. Battery temp takes priority over cabin temp. As a result, if the battery is cold, you may be cold. You may notice inconsistent heat at different times. It's related to the battery temperature.

As a reminder, follow these tips:

• Plug in the car when it's below freezing as much as possible to keep the battery warm. Every night.
• Set a departure time before any trips longer than approximately 15 minutes (warms the battery up fully).
• Use a Level 2 charger instead of Level 1 (L1 doesn't provide enough heating power).
• Make sure your EVSE is set to allow charging anytime and your charging hours aren't overly restrictive (≥8 hours per day).
• If you can't plug in, then run a remote start for 10-15 minutes before leaving. It's much easier to warm the cabin up when the car is stationary vs. driving.
• LIMIT FAN SPEED to a medium level or less (≤3). High fan speeds actually cool down the cabin in extreme cold.
• Use a moderate heat setting of 65-72ºF (18-22ºC) to avoid excessive fan speed and energy loss. Turning it up hotter won't help.
• Park in a garage rather than outside. This can keep the battery a lot warmer.
• If possible, drive slower. This will reduce convective heat loss.

Owners are experiencing lack of heat when parking the vehicle outside unplugged, or when they have extremely restrictive charging hours that don't allow the battery to draw power to for heating. The EVSE must allow charging at the time you are performing a departure time, or it won't work.

If you have a time-of-use rate plan, you may need to allow some charging to occur during peak times so the battery can heat. The small added expense from this may be well worth having heat. I see about 3 kWh usage to complete a full departure time (typically costs <50¢/day). I would avoid the highest peak times, but if you have a mid-peak rate, that would be okay for preconditioning use because the usage will be small. In cold weather, I recommend setting a departure time at least once a day before the anticipated time of vehicle use (battery stays warm for hours afterwards). If you don't have a regular schedule, you can set a battery-only departure time to reduce energy use. For more information about how/when to set departure times, see my other topic: Mach-Lee's Cold Weather Charging Strategies

For example, I have my EVSE set to allow charging at any time 24/7 and my charging hours in the car are set from 10PM to 10AM. I would set it this way even if my rate plan ended at 6 AM. The car usually only charges a for a couple hours (always done before 6 AM), but can automatically heat itself if necessary up until 10 AM. Departure times will still work anytime because the EVSE allows charging.

The heater in the Mach-E is undersized for extreme cold (only 5 kW) and may not be able to keep the cabin fully warm in temps below 5ºF/-15ºC even after following all the tips. Dress warmly. The minimum operating temperature of the Mach-E is around -31ºF/-35ºC, you may have zero cabin heat available around that temp. If the battery gets too cold, you'll enter turtle mode and have almost no power (can't maintain speed). Full heater output will be diverted to the battery, but in extreme cold that might not even be enough.

Cold weather requires some changes when driving an EV. You're living plug-to-plug in the extreme cold, and the ability to draw Level 2 power for heating becomes critical.

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[breeves002]

You’d think Ford would have done extreme cold testing that many of its owners experience. They would come to the conclusion the system in the Mach E is not adequate as shipped. Too bad.

Last winter I had to park at a friends house for 8+ hours outside in single digit temps. When I went to drive home I remote started twice. The cabin was warm when I got in but I got no heat at all the entire drive home. The windows were fogging up. I assume it was trying to heat the battery. This is just plain dangerous.

Thanks for giving this info to others that may not understand they may actually need to put in effort to stay warm in a car….

 

[devguynate]

Thanks for all the work you do @Mach-Lee surrounding this vehicle. I learn so much every time you post here and probably wouldn’t have been half as prepared for winter without some of your previous research!! Kudos, and thank you for the extra details!!

 

[Neil4Real]

You’d think Ford would have done extreme cold testing that many of its owners experience. They would come to the conclusion the system in the Mach E is not adequate as shipped. Too bad.

Last winter I had to park at a friends house for 8+ hours outside in single digit temps. When I went to drive home I remote started twice. The cabin was warm when I got in but I got no heat at all the entire drive home. The windows were fogging up. I assume it was trying to heat the battery. This is just plain dangerous.

Thanks for giving this info to others that may not understand they may actually need to put in effort to stay warm in a car….

So if in this situation again, would the best move be to turn off auto shut off and turn the car on a few hours before you planned to leave?

 

[HuntingPudel]

So if in this situation again, would the best move be to turn off auto shut off and turn the car on a few hours before you planned to leave?

If the car isn't plugged into an L2, it's only going to preheat the cabin (which will get cold during the drive home). ??

 

[Neil4Real]

If the car isn't plugged into an L2, it's only going to preheat the cabin (which will get cold during the drive home). ??

I’m so confused. That’s what @Mach-Lee has said before but then in this post he said: “If the battery is cold, the Mach-E will steal your cabin heat to warm the battery. The heater is shared between the battery and cabin. Battery temp takes priority over cabin temp. As a result, if the battery is cold, you may be cold. You may notice inconsistent heat at different times. It's related to the battery temperature.”

Wouldn’t this mean that turning your car on but not driving it would just heat the battery?

 

[Mach-Lee]

So if in this situation again, would the best move be to turn off auto shut off and turn the car on a few hours before you planned to leave?

I need to test that, I'm not sure if low battery temp will kick in battery heating in park or if you have to be moving/in drive first. It's based on cabin heat demand so can be tricky to catch. I don't see it happen often.

The battery heating while driving in this situation is sort of special circumstance that only kicks in when the battery is extremely cold. You don't want it to get that cold normally if you can help it.

 

[JohnFoxeSheets]

@Neil4Real, @HuntingPudel, seems unlikely we Californias will experience these issues anytime soon... But I always read Lee's posts as they're always very informative.

 

[Guss-E 2021]

I'm fortunate in that I'm able to do everything on Lee's list and do. I'm in NH. It's been unseasonally warmer here these past winters. Good for my oil costs and BEV ownership (though bad for planetary reasons).

Still, we've had overnights and mornings in the teens. I get into a warm MME every morning and have a short 12 mile drive to work. I have an end of work day departure time set but, so far, the daytime highs have been in 40's so the car has not had to work very hard.

 

[JeffGo]

Thanks @Mach-Lee. This answers my wife's question from yesterday: shouldn't we just plug in every night? My car is outside, and we are in the midst of a cold snap 13-25F, which is pretty unusual for us. Blucifer was plugged in Friday night, Saturday we had no issues with the heat (and I pre-warmed it before we went out). But we are using a lot more kWh/mi (as expected).

 

[Silvernort]

@Mach-Lee Great suggestions. I set my preferred times to 10p to 10a as you suggested and also increased the target from 70% to 80%. One of the more difficult things as far as scheduling from a care-of-the-vehicle standpoint is how variable our weather has been here in Wisconsin, as you are well aware. Going from mild, above average winter to suddenly subzero can't be good for our cars. IDK
The one question I have is how do you know if the preconditioning is actually happening? I have it set to precondition every morning but since I'm retired, may not drive for days at a time. It would be nice to know if it is in fact warming the battery. Suggestions?

 

[Kmp14]

@Mach-Lee Thanks as always, very informative! One question: My TOD pricing cheap window is 10PM - 6AM, so I have my MME set to charge during that time. I do not restrict the time in my EVSE at all. Will the MME kick in to warm the battery whenever it needs to, or only during my home location set charging window of 10PM - 6AM?

 

[RickMachE]

@Mach-Lee Great suggestions. I set my preferred times to 10p to 10a as you suggested and also increased the target from 70% to 80%. One of the more difficult things as far as scheduling from a care-of-the-vehicle standpoint is how variable our weather has been here in Wisconsin, as you are well aware. Going from mild, above average winter to suddenly subzero can't be good for our cars. IDK
The one question I have is how do you know if the preconditioning is actually happening? I have it set to precondition every morning but since I'm retired, may not drive for days at a time. It would be nice to know if it is in fact warming the battery. Suggestions?

The only way you KNOW is with an OBD reader and Car Scanner. FordPass displays a "Preparing for Drive" message, if you look at the right time.

 

[slambertr]

Wanted to write a note about this since many people are currently experiencing extreme cold temps (below 14ºF/-10ºC). In a nutshell:

Keeping the battery is warm is important so you have enough cabin heat!

If the battery is cold, the Mach-E will steal your cabin heat to warm the battery. The heater is shared between the battery and cabin. Battery temp takes priority over cabin temp. As a result, if the battery is cold, you may be cold. You may notice inconsistent heat at different times. It's related to the battery temperature.

As a reminder, follow these tips:

• Plug in the car when it's below freezing as much as possible to keep the battery warm. Every night.
• Set a departure time before any trips longer than approximately 15 minutes (warms the battery up fully).
• Use a Level 2 charger instead of Level 1 (L1 doesn't provide enough heating power).
• Make sure your EVSE is set to allow charging anytime and your charging hours aren't overly restrictive (≥8 hours per day).
• If you can't plug in, then run a remote start for 10-15 minutes before leaving. It's much easier to warm the cabin up when the car is stationary vs. driving.
• LIMIT FAN SPEED to a medium level or less (≤3). High fan speeds actually cool down the cabin in extreme cold.
• Use a moderate heat setting of 65-72ºF (18-22ºC) to avoid excessive fan speed and energy loss. Turning it up hotter won't help.
• Park in a garage rather than outside. This can keep the battery a lot warmer.
• If possible, drive slower. This will reduce convective heat loss.

Owners are experiencing lack of heat when parking the vehicle outside unplugged, or when they have extremely restrictive charging hours that don't allow the battery to draw power to for heating. The EVSE must allow charging at the time you are performing a departure time, or it won't work.

If you have a time-of-use rate plan, you may need to allow some charging to occur during peak times so the battery can heat. The small added expense from this may be well worth having heat. I see about 3 kWh usage to complete a full departure time (typically costs <50¢/day). I would avoid the highest peak times, but if you have a mid-peak rate, that would be okay for preconditioning use because the usage will be small. In cold weather, I recommend setting a departure time at least once a day before the anticipated time of vehicle use (battery stays warm for hours afterwards). If you don't have a regular schedule, you can set a battery-only departure time to reduce energy use. For more information about how/when to set departure times, see my other topic: Mach-Lee's Cold Weather Charging Strategies

For example, I have my EVSE set to allow charging at any time 24/7 and my charging hours in the car are set from 10PM to 10AM. I would set it this way even if my rate plan ended at 6 AM. The car usually only charges a for a couple hours (always done before 6 AM), but can automatically heat itself if necessary up until 10 AM. Departure times will still work anytime because the EVSE allows charging.

The heater in the Mach-E is undersized for extreme cold (only 5 kW) and may not be able to keep the cabin fully warm in temps below 5ºF/-15ºC even after following all the tips. Dress warmly. The minimum operating temperature of the Mach-E is around -31ºF/-35ºC, you may have zero cabin heat available around that temp. If the battery gets too cold, you'll enter turtle mode and have almost no power (can't maintain speed). Full heater output will be diverted to the battery, but in extreme cold that might not even be enough.

Cold weather requires some changes when driving an EV. You're living plug-to-plug in the extreme cold, and the ability to draw Level 2 power for heating becomes critical.

Great advice / reminder for all as cold weather hits the East Coast - thank you!

 

[HuntingPudel]

Thanks @Mach-Lee. This answers my wife's question from yesterday: shouldn't we just plug in every night? My car is outside, and we are in the midst of a cold snap 13-25F, which is pretty unusual for us. Blucifer was plugged in Friday night, Saturday we had no issues with the heat (and I pre-warmed it before we went out). But we are using a lot more kWh/mi (as expected).

Generally, yes. You should plug in every evening so that your preconditioning time setting will condition the battery if it's super-cold or super-hot out. If you are not plugged in, the car will not heat or cool the battery before a drive. Where I live that isn't really a problem, but there are a lot of people who do experience the extreme swings in temperature that make this necessary. ??

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