Cabin Heater cannot keep up below -20c at highway speeds

[Jimrpa]

I wonder if it would be possible to put in a separate, dedicated heat pump system for the HVB and an independent system (say electric resistance heat) for the cabin? ?‍

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[Mach-Lee]

I don’t know if it’s just my vehicle, but my 2021 MME premium can’t keep the cabin warm below -20c temperatures. Especially going higher speeds when the motors need more power. Is the battery just not able to distribute energy efficiently enough to keep the interior warm? Im wondering if this is a common issue? I really have to bundle up in these cold Saskatchewan winters when I make my daily commute. It’s getting tiring. I have made a service request at my local dealer to look into it, but I immediately received a text back from them saying nothing can be done about it. And then was told to buy an auxiliary heater, which are all terrible quality. Ridiculous. Any suggestions?

Known issue, the 5kW heater isn't big enough to keep up. If you want more heat, you should think about these mods:

• Ceramic window films to reflect heat
• Reflectix sheet for glass roof
• Insulate heater hoses with 3/8" pipe insulation
• Insulate bottom of battery pack with 1/2" foam

Make sure you are plugging into a Level 2 charger rated for 30 amps or more each night, and set a departure for when you usually leave. If you can plug in at work, set a second departure time for the trip home. More info: https://www.macheforum.com/site/threads/mach-lees-cold-weather-charging-strategies.24548/ Bare minimum you need to use remote start to get things warmed up before you start moving. If you don't plug in at night, cabin heat may be sacrificed for battery heating. Leave the car plugged in as much as possible, even if Level 1 is the only option.

The HVAC settings are also important, do not manually increase fan speed. Use the AUTO function only, and set a moderate temperature 16-20ºC, do not set it higher than 20ºC. I recommend using 20ºC AUTO 1 as the setting. Low fan speeds retain more heat. Some cyclical window fog is normal, that will usually clear on its own within 30 seconds if you ignore it. If it's bad enough, then use the regular defrost button under the HVAC controls drawer until it's gone, then switch back to AUTO mode. Do not use MAX Defrost unless absolutely necessary, that can actually cool down the cabin due to the high fan speed.

All the above comes from experience and lots of cold weather testing.

 

[Guss-E 2021]

Temps here in NH have been ranging between single digits (°F) and 30°F before factoring in wind chill. I only have eight miles of highway between home and work though. Car sits in a garage under my bedroom, plugged in every night. Heat is set to 70°F on Auto 1.

Departure Time/preconditioning also heats the steering wheel and seats (on 3). The car is usually warm enough that I can turn both of those off before pulling out. So far staying warm while driving hasn't been an issue. I'm driving between 70 and 75mph.

Of course the OP is talking temps a good 20 degrees cold than what I'm dealing with. I imagine the commute is longer too. Hope some of the suggested mods work.

 

[ipca204]

Temps here in NH have been ranging between single digits (°F) and 30°F before factoring in wind chill. I only have eight miles of highway between home and work though. Car sits in a garage under my bedroom, plugged in every night. Heat is set to 70°F on Auto 1.

Departure Time/preconditioning also heats the steering wheel and seats (on 3). The car is usually warm enough that I can turn both of those off before pulling out. So far staying warm while driving hasn't been an issue. I'm driving between 70 and 75mph.

Of course the OP is talking temps a good 20 degrees cold than what I'm dealing with. I imagine the commute is longer too. Hope some of the suggested mods work.

in case you are unaware. windchill has ZERO effect on machinery. Not trying to be a smart ass, but there are a surprisingly large number of people that think that it does.

 

[Guss-E 2021]

in case you are unaware. windchill has ZERO effect on machinery. Not trying to be a smart ass, but there are a surprisingly large number of people that think that it does.

Machinery is immune to convective heat loss? That seems odd but I'll take your word for it. Regardless ambient single digit temps are still cold ?.

 

[Maquis]

in case you are unaware. windchill has ZERO effect on machinery. Not trying to be a smart ass, but there are a surprisingly large number of people that think that it does.

In the case of evaporative windchill (which causes our skin to feel colder), than‘s correct.
But wind keeps the air temp in contact with surfaces closer to ambient than if there was no air movement, increasing conductive losses. If air movement had no effect, you wouldn’t need a fan on your home AC condenser unit. Think of the car surface as a sort of (inefficient) heat exchanger.

 

[Womps]

Temps here in NH have been ranging between single digits (°F) and 30°F before factoring in wind chill. I only have eight miles of highway between home and work though. Car sits in a garage under my bedroom, plugged in every night. Heat is set to 70°F on Auto 1.

Departure Time/preconditioning also heats the steering wheel and seats (on 3). The car is usually warm enough that I can turn both of those off before pulling out. So far staying warm while driving hasn't been an issue. I'm driving between 70 and 75mph.

Of course the OP is talking temps a good 20 degrees cold than what I'm dealing with. I imagine the commute is longer too. Hope some of the suggested mods work.

So are you preconditioning your batteries for an 8 mile trip?

 

[A-A-Ron]

it’s a physical design battery pack issue combined with the fact that you are relying on what’s basically a big space heater to keep warm, not waste heat from an engine.

It's amazing people don't realize that EV's have to actually use power to create heat and that the system was only designed (probably underdesigned, at least until the heat pump came in) to generate so much.

As opposed to ICE, which are literally heat generators and you have to steal some heat to make movement.

 

[Adventureboy]

Make sure your coolant is not low. This can cause cabin heat issues since the cabin heater is above the battery and it uses the same fluid system. The tank is behind the frunk, under the hood - you need to pop the cover off (be careful not to lose the connectors). It is a known problem that these EVs come from the factory with air in the system and need to be topped up as the air burps out. Rule that out first.

 

[Tomatoboy]

in case you are unaware. windchill has ZERO effect on machinery. Not trying to be a smart ass, but there are a surprisingly large number of people that think that it does.

Yes, wind chill temperature is how cold *people and animals* feel when outside. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder.

It *is* however a good indicator that conductive heat loss will be greater in machinery, because it suggests greater air movement in cold weather. Since this is a conductive heat loss issue it’s relevant, as heat losses on a day with a lower wind chill reading can be assumed to be higher than a day with an identical actual temperature but higher wind chill reading.

 

[Guss-E 2021]

So are you preconditioning your batteries for an 8 mile trip?

That's incidental. My goal is warming the cabin up while still plugged in as is generally recommended. I would love it if battery temperature info was available on our displays though.

To be specific my drive is 12 miles to the office (28 if I have to bring my son to school first) ?.

 

[MadMatt]

so I've got a 2024 LFP. only 2-3 weeks old now.

i keep the interior set to 20c (68f). From what I've noticed driving around in -15c temps the car does a good job keeping warm, however for some reason when i take a turn at higher speeds i feel a rush of cold air on my legs. There's some side insulation that doesn't handle crosswind very well. nothing audible however.

 

[Mach-Lee]

so I've got a 2024 LFP. only 2-3 weeks old now.

i keep the interior set to 20c (68f). From what I've noticed driving around in -15c temps the car does a good job keeping warm, however for some reason when i take a turn at higher speeds i feel a rush of cold air on my legs. There's some side insulation that doesn't handle crosswind very well. nothing audible however.

Feeling cold air on a turn is not an air leak, it's happening because the dense cold air shifts to the outside of the turn. The centrifugal force during the turn is what causes it. You will notice the cold only during right turns on the driver's side. Imagine if your car was filled with 3" of water, when you turn that water will slosh to the outside of the turn, it's the same with the cold air.

 

[laxwiz]

Hope you get some kind of answer. My ‘21 Premium does fine on the highway at 75mph.

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