Turtle Mode (Cold Weather Warning)

[Billyk24]

The Mach E like other EV's has a protective plates covering over the battery pack. Lets call this a multi-piece skid plate. If we remove the skid plates and apply on the inside of each skid plate insulation with adhesive backing as shown in the photo, file attachment, then we could better control the heat loss of the battery pack? How much room exist between these skid plates and the actual battery pack covering?

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[Shayne]

Agree, I think a change needs to be made ASAP for winter, especially relevant in Canada.

The heating system logic that it shipped with at the beginning of 2021 was the best for me so far (split) but I dress for the climate. Keep shutting cabin heat down for the batteries makes no sense. I will keep setting departure schedules to warm them up. Drives and regens better setting a departure on L2 when cold.

It would be nice if they tweaked the charging curve and make it reasonable to get up to 90%. That is an easy improvement to get more out of the car in the cold.

Joining this thread because we have been giving some serious consideration to an MME-X for my wife's commute to work (220km return), but our winters see at least a few good stretches of NEGATIVE Fahrenheit temperatures and definitely plenty of time under 20*F. Threads like this and posts on MME sub-Reddits are causing us some serious pause.

Also, what is it about people drawing comparisons or offering experiences to down right balmy conditions in posts that are specifically targeted at ACTUAL WINTER TEMPERATURES? Get outta here with your "mine didn't do this when I was out driving in "cold" 40*F temps yesterday" ?

No problems commuting up here in the cold has worked great. Setting a departure schedule at home and having a place to plug in a work would help (L2 and departure at work would be the cats meow). This car has never been a problem for me in the cold but I only have a 40 Km commute (80 round) and do not do a lot of road tripping when -20C. 220 Km you will need to charge it every night and to a high state of charge as you can never use 100% range and range is noticeably reduced in the cold. That will take some learning for her route at different temps. Going to save some cash with that commute and charging batteries not pumping gas.

 

[GarageWarrior2023]

So, I seem to recall in the past year(?) a 3rd party vendor who was marketing an underbelly insulation add-on for the Mach-e. To increase insulation of battery. Anyone else remember this?

That was me, but I wasn't marketing a kit so much as lobbying Ford to create a cold weather kit that address the convection cooling issues of the mach-e's panoroof and battery that causes them to not work as designed in winter.
https://www.macheforum.com/site/threads/mach-e-cold-weather-kit-who-wants-one.33781/

I strongly believe that Fords original designs must have included a thermal break material between the coolant plates and the battery enclosure (bottom of the battery). There's room for it, and if you compare the enclosure design to that of the Bolt EUV (I owned one of those before the mach-e) the design is extremely similar except on a teardown of the mach-e battery you see a clear lack of thermal break material, whereas the bolt has thermal break material.

Ford is famous for having many separate departments making uncommunicated and untested changes to aspects of the vehicle late in development and beyond. My best guess is the vehicle was designed to have insulation and later that component was missed or intentionally omitted for production ordering and building of the batteries. Ford has since avoided the root cause, thrown a larger heater at the issue and now is dabbling in heat pumps. The original design was correct and the heater I believe was spec'd correctly, provided there is a thermal break between the coolant plates and the battery enclosure.

The only other alternative to this additional thermal break material is to utilize a non-thermally conductive battery enclosure material (other ev manufacturers with cold weather success have implemented this alternative). This is as per Sandy Monroe's commenting on tearing down the mach-e battery and being confused as to why the enclosure was thermally conductive and did not include a thermal break. He commented on this saying you want a thermal break to ensure that external temperature variables do not affect battery and heating/cooling performance.

My bolt EUV had zero range or heating issues in -40c. the range was extremely consistent and linear. The other thing was that I had no insane software induced limitations at low states of charge in the cold either.

Yes @Billyk24 I believe there is room for a thermal break material in the battery, and I believe it was supposed to be there in the first place.

The Mach E like other EV's has a protective plates covering over the battery pack. Lets call this a multi-piece skid plate. If we remove the skid plates and apply on the inside of each skid plate insulation with adhesive backing as shown in the photo, file attachment, then we could better control the heat loss of the battery pack? How much room exist between these skid plates and the actual battery pack covering?

Everyone with a mach-e who operates in cold climates like Canada and the upper US snow belt has been at their wits end with the drawn out lack of action and response to the cold weather issues that are unique to Ford EV's. Ford needs to respond, release a CSP of some kind to address the lack of insulation/thermal break on our batteries to fix the root issue. And release a corrective update to restore the originally allowed voltage sag value of our batteries so that we can use our vehicles below 30%SOC in winter safely again. As @Mach-Lee has stated, the battery will be warm and even then you will be flagged with a "battery extremely cold" warning, this indicates to me that a value change was made that now throws other calculations and trigger points off. I agree with @Mach-Lee that there was most likely no testing or research done on the voltage change before being made.

OTA updates were supposed to improve our vehicles over time. Locking us out of up to 30% of our usable range with software limitations in cold weather after purchasing them is not only NOT an improvement, but is unacceptable and in my opinion quite possibly has serious legal implications if not corrected.

Sorry for the rant everyone, but I'm at my absolute limit for frustration after pushing dealerships and Ford for almost a year now on 2 core issues that are easily fixable.

 

[Billyk24]

That was me, but I wasn't marketing a kit so much as lobbying Ford to create a cold weather kit that address the convection cooling issues of the mach-e's panoroof and battery that causes them to not work as designed in winter.
https://www.macheforum.com/site/threads/mach-e-cold-weather-kit-who-wants-one.33781/

I strongly believe that Fords original designs must have included a thermal break material between the coolant plates and the battery enclosure (bottom of the battery). There's room for it, and if you compare the enclosure design to that of the Bolt EUV (I owned one of those before the mach-e) the design is extremely similar except on a teardown of the mach-e battery you see a clear lack of thermal break material, whereas the bolt has thermal break material.

Ford is famous for having many separate departments making uncommunicated and untested changes to aspects of the vehicle late in development and beyond. My best guess is the vehicle was designed to have insulation and later that component was missed or intentionally omitted for production ordering and building of the batteries. Ford has since avoided the root cause, thrown a larger heater at the issue and now is dabbling in heat pumps. The original design was correct and the heater I believe was spec'd correctly, provided there is a thermal break between the coolant plates and the battery enclosure.

The only other alternative to this additional thermal break material is to utilize a non-thermally conductive battery enclosure material (other ev manufacturers with cold weather success have implemented this alternative). This is as per Sandy Monroe's commenting on tearing down the mach-e battery and being confused as to why the enclosure was thermally conductive and did not include a thermal break. He commented on this saying you want a thermal break to ensure that external temperature variables do not affect battery and heating/cooling performance.

My bolt EUV had zero range or heating issues in -40c. the range was extremely consistent and linear. The other thing was that I had no insane software induced limitations at low states of charge in the cold either.

Yes @Billyk24 I believe there is room for a thermal break material in the battery, and I believe it was supposed to be there in the first place.


Everyone with a mach-e who operates in cold climates like Canada and the upper US snow belt has been at their wits end with the drawn out lack of action and response to the cold weather issues that are unique to Ford EV's. Ford needs to respond, release a CSP of some kind to address the lack of insulation/thermal break on our batteries to fix the root issue. And release a corrective update to restore the originally allowed voltage sag value of our batteries so that we can use our vehicles below 30%SOC in winter safely again. As @Mach-Lee has stated, the battery will be warm and even then you will be flagged with a "battery extremely cold" warning, this indicates to me that a value change was made that now throws other calculations and trigger points off. I agree with @Mach-Lee that there was most likely no testing or research done on the voltage change before being made.

OTA updates were supposed to improve our vehicles over time. Locking us out of up to 30% of our usable range with software limitations in cold weather after purchasing them is not only NOT an improvement, but is unacceptable and in my opinion quite possibly has serious legal implications if not corrected.

Sorry for the rant everyone, but I'm at my absolute limit for frustration after pushing dealerships and Ford for almost a year now on 2 core issues that are easily fixable.

Someone with a lift needs to remove the skid plates and add such thermal insulation. Then field test such.

 

[GarageWarrior2023]

Someone with a lift needs to remove the skid plates and add such thermal insulation. Then field test such.

Unfortunately the way the battery is designed, it's not a skid plate. it's a battery tray, so to test in that way you would have to lift the vehicle, drop the battery tray out ( lower out the entire battery pack), open it up, lift out all the battery modules and cooling plates and then put the thermal break material in and reassemble then reinstall the battery tray

This was why I was lobbying Ford for an extreme weather kit that was more like adding a bolt up insulation skid plate of sorts. To simplify the deployment.

But, someone could test creating an external thermal break that covers the entire underside of the battery if they wished. This would be possible for someone with a lift, absolutely.

 

[Wes8398]

That was me, but I wasn't marketing a kit so much as lobbying Ford to create a cold weather kit that address the convection cooling issues of the mach-e's panoroof and battery that causes them to not work as designed in winter.
https://www.macheforum.com/site/threads/mach-e-cold-weather-kit-who-wants-one.33781/

I strongly believe that Fords original designs must have included a thermal break material between the coolant plates and the battery enclosure (bottom of the battery). There's room for it, and if you compare the enclosure design to that of the Bolt EUV (I owned one of those before the mach-e) the design is extremely similar except on a teardown of the mach-e battery you see a clear lack of thermal break material, whereas the bolt has thermal break material.

Ford is famous for having many separate departments making uncommunicated and untested changes to aspects of the vehicle late in development and beyond. My best guess is the vehicle was designed to have insulation and later that component was missed or intentionally omitted for production ordering and building of the batteries. Ford has since avoided the root cause, thrown a larger heater at the issue and now is dabbling in heat pumps. The original design was correct and the heater I believe was spec'd correctly, provided there is a thermal break between the coolant plates and the battery enclosure.

The only other alternative to this additional thermal break material is to utilize a non-thermally conductive battery enclosure material (other ev manufacturers with cold weather success have implemented this alternative). This is as per Sandy Monroe's commenting on tearing down the mach-e battery and being confused as to why the enclosure was thermally conductive and did not include a thermal break. He commented on this saying you want a thermal break to ensure that external temperature variables do not affect battery and heating/cooling performance.

My bolt EUV had zero range or heating issues in -40c. the range was extremely consistent and linear. The other thing was that I had no insane software induced limitations at low states of charge in the cold either.

Yes @Billyk24 I believe there is room for a thermal break material in the battery, and I believe it was supposed to be there in the first place.


Everyone with a mach-e who operates in cold climates like Canada and the upper US snow belt has been at their wits end with the drawn out lack of action and response to the cold weather issues that are unique to Ford EV's. Ford needs to respond, release a CSP of some kind to address the lack of insulation/thermal break on our batteries to fix the root issue. And release a corrective update to restore the originally allowed voltage sag value of our batteries so that we can use our vehicles below 30%SOC in winter safely again. As @Mach-Lee has stated, the battery will be warm and even then you will be flagged with a "battery extremely cold" warning, this indicates to me that a value change was made that now throws other calculations and trigger points off. I agree with @Mach-Lee that there was most likely no testing or research done on the voltage change before being made.

OTA updates were supposed to improve our vehicles over time. Locking us out of up to 30% of our usable range with software limitations in cold weather after purchasing them is not only NOT an improvement, but is unacceptable and in my opinion quite possibly has serious legal implications if not corrected.

Sorry for the rant everyone, but I'm at my absolute limit for frustration after pushing dealerships and Ford for almost a year now on 2 core issues that are easily fixable.

You're my kinda forum member. I've been heavily involved in various automotive forums since way back when they were the only place to go for information outside of service & consumer manuals. Your contributions are awesome, so thank you for that. If you already have contact info for people/departments at Ford that can actually make things happen, please share. I'd be happy to spam them with concerns about safety, etc. ?

 

[GarageWarrior2023]

You're my kinda forum member. I've been heavily involved in various automotive forums since way back when they were the only place to go for information outside of service & consumer manuals. Your contributions are awesome, so thank you for that. If you already have contact info for people/departments at Ford that can actually make things happen, please share. I'd be happy to spam them with concerns about safety, etc. ?

Thanks! Glad I can add value where possible.

Nothing I could give you other than recommending spamming the BEV support line rather than the general support line.

I wonder if anyone else on this forum has a good contact at Ford with some pull in the BEV division? Anyone got an inside man?

I had a couple good agents I worked with for short periods but I can't give their direct emails out, and they are merely a conduit to the people who have more decision making power. I never managed to get directly to anyone internal with higher authority. I've gone through local dealership chains of command from the bottom to the top, and tried to get information to local field engineers. Dealt with multiple dealerships. All the normal channels you'd expect.

 

[Mach-Lee]

Tesla allows significantly more voltage sag than Ford. On a Tesla Model 3 (also 400V), I've seen reports of the pack voltage getting as low as 240V under load (vs. Ford's 310V limit). Granted the sag may be less than that when the battery is under similar conditions (low SoC and cold temp), but I believe Tesla would almost always allow sag below 300V. On Bjørn's videos I see it go down to 280-290V pretty regularly.

So in summary, Ford limits to only 3.3V/cell, but Tesla routinely allows 3.0V/cell and even down to 2.5V/cell under extreme load.

So just to provide an update, it got very cold here and the battery temp had dropped to about -11ºC/12ºF by the time I went home today. Battery level was around 55%. During a peak load, the battery voltage dropped all the way down to 286V. That translates to about 3.0V/cell.

What this means is that Ford DOES allow appropriate discharge voltage limits in a cold battery at higher SoC but imposes much stricter limits at low SoC. This doesn't make much sense as a protection strategy. Increasing the voltage limit at low SoC does not significantly mitigate degradation risks which are primary associated with extremely low cell voltages (below 2.7V).

There is still a slight elevated risk of degradation running a battery to low SoC at low temp due to ion mobility problems, but a more appropriate control strategy would be to use a dynamic bottom buffer rather than severely limiting voltage sag. In other words, cold temp degradation is more associated with low SoC levels than pack voltage sag.

In summary, I believe a uniform discharge limit of 3.0V at all SoC levels could likely be used without much risk (this is probably how it used to be). It would be more appropriate to dynamically increase the bottom buffer in cold conditions (e.g. the actual SoC changes where 0% is displayed) so decent power levels are always available down to lets say 5% indicated without the customer experiencing a turtle mode.

Switching to a dynamic bottom buffer would eliminate the problem of turtle mode appearing at 20% displayed charge. The customer satisfaction aspect of the software design should be weighed more heavily than the potential risk of slightly increased battery degradation.

 

[Jdudley]

So just to provide an update, it got very cold here and the battery temp had dropped to about -11ºC/12ºF by the time I went home today. Battery level was around 55%. During a peak load, the battery voltage dropped all the way down to 286V. That translates to about 3.0V/cell.

What this means is that Ford DOES allow appropriate discharge voltage limits in a cold battery at higher SoC but imposes much stricter limits at low SoC. This doesn't make much sense as a protection strategy. Increasing the voltage limit at low SoC does not significantly mitigate degradation risks which are primary associated with extremely low cell voltages (below 2.7V).

There is still a slight elevated risk of degradation running a battery to low SoC at low temp due to ion mobility problems, but a more appropriate control strategy would be to use a dynamic bottom buffer rather than severely limiting voltage sag. In other words, cold temp degradation is more associated with low SoC levels than pack voltage sag.

In summary, I believe a uniform discharge limit of 3.0V at all SoC levels could likely be used without much risk (this is probably how it used to be). It would be more appropriate to dynamically increase the bottom buffer in cold conditions (e.g. the actual SoC changes where 0% is displayed) so decent power levels are always available down to lets say 5% indicated without the customer experiencing a turtle mode.

Switching to a dynamic bottom buffer would eliminate the problem of turtle mode appearing at 20% displayed charge. The customer satisfaction aspect of the software design should be weighed more heavily than the potential risk of slightly increased battery degradation.

How cold was it when your battery got that cold? This whole turtle mode thing is making me kinda paranoid, I just got a new 2024 AWD SR last month and now feeling like I should've gotten the ER. I live in PA where it can potentially get down into the single digits some days but it's generally ~20-30 from December-Feb.

Work commute is completely fine, but the round trip to visit the family is ~100 miles and I can't plug it in there most likely, and it's 80%-85% highway driving so going to be burning battery more. When I bought the car I was assuming even if I lost half my battery range in the winter I'd be completely fine, but now I'm worrying about this turtle mode.

 

[redgrandam]

Any idea what battery temp it will actually be trying to heat the battery at when driving (and not routed to a charger). I have an LFP so want to test this but not sure what range I need to get to. When it was -11C out the battery got down to about -8C while at work and although the battery warmed up a bit on my hour drive home it didn’t seem to be actively warming it.

outside temps have warmed up here again but when it cools down again I’ll try to test some things out.

 

[Mach-Lee]

Any idea what battery temp it will actually be trying to heat the battery at when driving (and not routed to a charger). I have an LFP so want to test this but not sure what range I need to get to. When it was -11C out the battery got down to about -8C while at work and although the battery warmed up a bit on my hour drive home it didn’t seem to be actively warming it.

outside temps have warmed up here again but when it cools down again I’ll try to test some things out.

It seems like it's trying to heat it up to 5ºC or so (my run-ins with turtle mode happened at 2ºC and 4ºC). However, this automatic battery heating seems to only kick in when the battery gets low (like below 25%). I've never seen it spontaneously occur at high states of charge even when the battery is below -10ºC.

The LFP strategy may be completely different (I'd love to get my hands on one for testing), but generally, LFP really wants to be above 0ºC. Because you have the bigger 7 kW heater, you may see a more active strategy with the LFP pack than the NCM packs. The fact that it didn't warm up is a bit concerning, especially if it still allowed regen at that -8ºC battery temp. I assume you checked your VIN to verify that you have a LFP pack?

 

[redgrandam]

It seems like it's trying to heat it up to 5ºC or so (my run-ins with turtle mode happened at 2ºC and 4ºC). However, this automatic battery heating seems to only kick in when the battery gets low (like below 25%). I've never seen it spontaneously occur at high states of charge even when the battery is below -10ºC.

The LFP strategy may be completely different (I'd love to get my hands on one for testing), but generally, LFP really wants to be above 0ºC. Because you have the bigger 7 kW heater, you may see a more active strategy with the LFP pack than the NCM packs. The fact that it didn't warm up is a bit concerning, especially if it still allowed regen at that -8ºC battery temp. I assume you checked your VIN to verify that you have a LFP pack?

Interesting. This is my third EV and none of the others ‘started’ battery heating at a low SOC, I fact my Tesla would STOP getting then.

Mine is. 2023.5 and it had LFP right on the window sticker. I bought it early 2024 so lines up.

My Tesla I had before this also had an LFP battery. If I recall correctly, it would heat the battery when driving normally if the battery temp was only a bit below 0. It would heat it till just above 0C.

It was quite surprising to me that my LFP battery in my Mach E was as cold as it was and still doing some (limited) regen and not actively heating.

From what I can tell the heating thresholds they have set up when plugged in at home (for charging and departure settings) is similar if not the same as NCM that I’ve read. Departure takes it up to around 15C, otherwise it just keeps it above freezing while plugged in at home.

Obviously I can trick it into heating the battery by putting in a charger into the destination but that’s annoying (and pointless for regular driving).

I’ll try to get it so the battery temp is below -10C and see what it does! I have a long daily commute so I can’t let it not charge most days, but it often sits for 10 hours in the late evening at work so it still can get cold.

 

[Mach-Lee]

My Tesla I had before this also had an LFP battery. If I recall correctly, it would heat the battery when driving normally if the battery temp was only a bit below 0. It would heat it till just above 0C.

That’s what it should be doing, heat to 0°C if it’s below. Especially on the LFP. That’s why they put the bigger heater in so it has enough power to do cabin and battery heating at the same time.

There are definitely some bugs in the current powertrain software I have, heating during Level 2 charging has stopped working (it runs the pump for a few minutes but no heat), and departure times only heat to 5°C instead of 15°C.

It wouldn’t surprise me if they put the wrong software on your car, so if you’re not seeing battery heating to 0°C after the cabin is fully warmed up, I would contact Ford. Regen should also be completely disabled when the battery is cold enough just like your LFP Tesla (check battery power, it should switch to 100% friction brakes).

 

[redgrandam]

That’s what it should be doing, heat to 0°C if it’s below. Especially on the LFP. That’s why they put the bigger heater in so it has enough power to do cabin and battery heating at the same time.

There are definitely some bugs in the current powertrain software I have, heating during Level 2 charging has stopped working (it runs the pump for a few minutes but no heat), and departure times only heat to 5°C instead of 15°C.

It wouldn’t surprise me if they put the wrong software on your car, so if you’re not seeing battery heating to 0°C after the cabin is fully warmed up, I would contact Ford. Regen should also be completely disabled when the battery is cold enough just like your LFP Tesla (check battery power, it should switch to 100% friction brakes).

Is there a place to contact ford directly to ask things like that? My local dealer won’t have a clue on that stuff.

funny thing is none of this is information that is available to a consumer without using the OBDII reader so the average consumer would have no idea. I have received multiple updates this year on the car. And I have yet to see another forum member with an LFP battery so I’m unable to compare with anyone else if this is by design or not.

if I set departure time it definitely gets up to 15C range for the battery. I have yet to get home with the battery below freezing and plug in to see what it does, but the battery is always above freezing still in the morning when I get up.

 

[CarlSagan82]

Is there a place to contact ford directly to ask things like that? My local dealer won’t have a clue on that stuff.

And I have yet to see another forum member with an LFP battery so I’m unable to compare with anyone else if this is by design or not.

You should make a thread and try to connect with other LFP owners to compare data and experiences

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