Turtle Mode (Cold Weather Warning)

[kltye]

For better or worse, my garage has managed to hover just around freezing. But here are the car scanner results:

This shows just regular charging. You can see my min temp is 32F and the max is 37.4F. No heating going on.

However, if I turn on the car (press brake pedal and push the start button), this happens:

(I know it looks like the car is charging slowly, but it was in the middle of its stupid "stop-charging-and-then-ramp-back-up-when-you-turn-on-the-car" dance when I took the screenshot)

For some reason it's only then that it decides to heat the battery pack. Climate control in the cabin was OFF, and I could hear the pumps, etc. I've also noticed this behaviour a few weeks ago and did see that the coolant temp was increasing, indicative of battery heating.

Sponsored

 

[GarageWarrior2023]

Thank you for your account. I'm guessing what happened was the battery didn't heat on Level 1 charging, so it was very cold around ambient temp when you left. This means Turtle mode will happen sooner. The battery can be heated while driving, but often there is not enough heater power available to heat both the battery and cabin at the same time. If the battery is really cold, it won't even try to heat it while driving because you would lose all your cabin heat. I just finished a test at -25ºC, starting with a +12ºC battery it still cooled off to 0ºC despite the battery being switched in and heated while driving. That's the best it could do.

If you can only Level 1 change in very cold temps, it's probably wise not to go below 30% charge unless you've verified the battery temp has warmed up above 0ºC.



Agree. The car either doesn't have enough available power to heat the battery above 0ºC during charging, or there could be a software issue preventing battery heating in some cases.

I have a request, if you're in the cold north and have Car Scanner, can you check on battery temps while charging? Specifically, if the battery is below freezing to start with, does it get heated above freezing immediately during AC charging or not? It would be good to get data from both Level 1 and 2 charging, and different model years.

The battery definitely doesn't heat while on 120v and actively charging. I have historically noticed no battery temperature increase over the course of a cold day(not even passively from the charging process). So you are most likely correct as to why it happened at 40%. Not sure how cold the battery was actually, but it was probably close to ambient as it always is. With that said, in the same conditions last year I had this happen at 30% rather than 40%, so that's why I find it interesting. Even down to the 120v charging all day.

The battery doesn't seem to get any warmer while charging, and doesn't attempt to heat. but if I were to hit stop on charging, then it will start to warm the battery using 120v shore power.

Interestingly, my Bolt EUV would warm the battery even if it wasn't plugged in. It would intermittently warm itself while plugged into 120v. So my total charge for the day was power in minus losses minus whatever it used to warm the battery that day. I would average a net positive of about 8-10% charge. the mach-e will do 25% charge from an 8.5 hour charge period, even in minus 30c. Which doesn't really make sense, because even if I were to say I was getting 1kw to the battery from the charger, for 8.5 hours, that's only something like 10-11% total charge on a standard range battery. So something is way off in Fords BMS for sure. Maybe the BMS is way out of calibration?

Battery definitely heats at level 2 charging. the first thing it does it start the coolant pump and heater when plugged in and cold. It follows the same logic that they seem to have since 2021, 120v is charge then heat, and 240v is heat then charge.

I also got at least 265km range in -35c in the bolt. where the best I can get in the mach-E is around 100km before turtle mode takes over.

Either way, I may have set the new record for turtle mode cutoff, so I wanted to share.

If I gather some data over OBD2 I will share as well

 

[Shayne]

I don't understand how the vehicle is allowing the battery pack to drop below 0c. Charging any lithium chemistry below freezing is immediately bad for the pack (and certainly at -17c), so either what we're seeing in CarScanner is wrong, or Ford is royally screwing things up.

I understand charging them frozen would cause mass degradation and make a time bomb of the pack that could explode if impacted. Based on the degradation we are seeing (last 4 years) I do not thing Ford has totally screwed up yet. You would think it would have surfaced by now if a problem existed.

I have no idea of the battery chemistry or what the electrolyte charging characteristics are. Are there batteries you can charge below 0C? Maybe not just Tesla has the secret sauce

 

[GarageWarrior2023]

I am not a big cold weather traveler. Not in a EV or a 4x4 ice off road truck. I do run around in the winter and the EV is my obvious choice. Love the torque in this car. I have not seen turtle mode to date as it rarely goes below 50% before back up to 80%. Plugged to L2 it auto conditions itself. Set departures and all warm/conditioned before leaving. Dress and be prepared for the conditions.

If you shut HVAC down it will heat the battery and turtle should go away. Crack a window so you do not fog. On my version of the software right now I can have fan without heat or a/c. One version I could not. Plan not to run it down to low %? It is so rare that work arounds will do.

Nothing is perfect that is why we develop work arounds. Early tech. They should go back to the original logic and put up with the people complaining that they can not take their jacket off in the car when -20C outside. There would be a law suit on that. I would prefer knowing the battery was OK to run and be a bit cooler in the cabin. With heat seats the original was no problem and comfortable. Having to manually toggle it off and on is not the best.

I agree completely. I have heard MANY people say that the originally shipped programming of the 2021 mach-e was by far the best for cold weather driving. battery performed better, you could use it down to very low states of charge without issues, and the BMS and GOM seemed to work better.

In terms of cold weather, I would much prefer Ford restore the old operation characteristics that allowed the use of the battery down to much lower SOC like 10-15% before any limiting happened. I would find this very reasonable for cold weather operation.

 

[GarageWarrior2023]

I understand charging them frozen would cause mass degradation and make a time bomb of the pack that could explode if impacted. Based on the degradation we are seeing (last 4 years) I do not thing Ford has totally screwed up yet. You would think it would have surfaced by now if a problem existed.

I have no idea of the battery chemistry or what the electrolyte charging characteristics are. Are there batteries you can charge below 0C? Maybe not just Tesla has the secret sauce

Ya don't you find it strange that they allow charging at low temp like that on 120v? No heating, just charge it........so weird......

Like you said though, no matter what anyone seems to throw at the batteries, they never seem to degrade much.......so who knows anymore........seems like following or not following best practices nets very close results a lot of the time.

 

[VindictivePantz]

Yesterday, I preconditioned, drove ~70MPH for ~30 miles, and all behaved well.

The car sat in a parking garage all day, and it was 8F with 160+ miles and around 70% SOC on the GOM. There were no chargers. so I knew the battery was cold, and expected less efficiency.

I drove ~70MPH for ~30 miles back home, and had 96 miles left, but SOC was around ~54%. The difference in drop in the GOM's mileage estimate vs. SOC was odd. I was never in danger of turtle mode, but seeing such a drop in mileage vs. SOC % makes cold weather driving even more perplexing. (FWIW, I was at 1.9 mi/kWh on the drive home.)

I don't have a car scanner (I should pick one up,) but it's well below freezing in my garage today and I've not seen/heard any evidence of the battery pock warming up while plugged-in, so assuming it has not dropped to whatever safety temperature it requires to kick in.

 

[Billyk24]

@MachLee I just had red turtle severe power limiting and the vehicle getting slowed down to a crawl at 40% SOC. at -29c outside. This seems to be even worse than before now. I had been at -34 and was able to go to 30% SOC before seeing yellow turtle and then red turtle shortly after, that was last year. Now this year this is our first time down to super cold temps and the behavior is different yet again.

I charged 120v all day at work like I normally do in the cold, total usage of battery was 86% to go 140km. I was at 69% arriving at work, and then after charging to 95% before leaving work I was down to 38% by the time I pulled into my driveway.....after driving very slowly on the highway for a short stint......luckily it was just a short stint of limiting.

I wish your battery temperature data was inputted. Then again, an app such as car scanner pro and ORB 2 reader is needed.

 

[kltye]

I understand charging them frozen would cause mass degradation and make a time bomb of the pack that could explode if impacted. Based on the degradation we are seeing (last 4 years) I do not thing Ford has totally screwed up yet. You would think it would have surfaced by now if a problem existed.

I have no idea of the battery chemistry or what the electrolyte charging characteristics are. Are there batteries you can charge below 0C? Maybe not just Tesla has the secret sauce

I think NiMH and lead acid are fine for below freezing. I know you can add cobalt to lithium batteries to give them better characteristics at low temperatures, but I doubt anything would work at -17c. Plus, cobalt isn't cheap and is a highly contested mineral, so I don't know how much of it is in our packs.

Tesla definitely doesn't have any secret sauce because their cars spend enormous amounts of energy (compared to us) keeping the pack at a happy temperature.

 

[GarageWarrior2023]

Late answer, but I just drove back home last Monday, starting at -40c (Northern Quebec), ending in Montreal at around -20c, and we had the turtle mode issue happened to us. We left my mom's house at around 90%, after being on 110V all night and warming up the car before leaving. We had no issues getting going, which was even a bit surprising for me (not my first time doing this, but first time with an electric car). We had about 170km to our first stop, with 20% estimated on arrival, which was in line with what ABRP was calculating. After the first 100km, we past the one town in between with fast charger, with just under 50% battery left, and no indication we would need to charge there, so I continued. Not too long after, the SoC started dropping faster; I assumed it was trying to precondition for the next charger. We didn't make it 20km when we got the yellow turtle mode, followed a minute after by the red turtle mode, and the car started slowing down. Luckily, we were passing the only Level 2 charger along that road, and were able to get there safely with 22% left, but it was very startling.

At that point, after plugging in, I went on CarScanner, and saw that the battery was around -17c, which was colder but not much more than what it had been the past couple days. There were no abnormal indications beside that, and that the HVB battery SoC was about 2% lower than the displayed battery SoC. We ended up spending a hour and half just to be able to warm up the battery and gain an extra 3% charge to make it to the charger, which the car did without issue; at that point, the battery was now up to maybe 5-10c.

I understand how lithium batteries do not perform in the cold, and that this was a bit of an extreme case; but I agree that this is very dangerous behavior. If the car knew it couldn't access that remaining energy due to cold temperature, they should do like Tesla and mark it as blue, cold soaked, or just lower the SoC appropriately. That would have also triggered the navigation and prompt me to charge earlier; better that than dying on you out of nowhere, especially when you still have 20-30% SoC showing. I cannot imagine for the life of me having to deal with this without CarScanner at least giving me some stats and helping us understand what happened; if I can access the data, they should be able to inform the driver in a way.

After that point, we had CarScanner running the whole trip home (took us 11 hours for a 700km trip), and after the battery was warmed up, it never gave us any issues, as it hovered between -5c and 20c during the trip. One thing I noted was that, unless we were charging and we had the car off, or at least the heat off, at no point the car could warm up the battery; it all went to the cabin heat, even when the cabin heating was not requesting the full 5.6kW from the heating system. You would think that they would have a split system similar to Tesla and maybe others, where it could use the excess heating capacity and divert it to the battery as needed. I agree that heating the cabin is a priority, but at no point the car preheated for any chargers we navigated to, even at higher SoC, and only stated the heating process once plugged in. We never saw anything higher than 90kW, even on 180-200kW chargers that can give 140-160kW usually.



Regarding the second part: We didn't freeze in the car, but you could tell the car was struggling to keep up, and was blowing cooler air out of the defrost vents than the foot well. Had it in Auto, level 3 fan; after manually setting it to bi-level and lower the fan speed, it felt better inside the car. CarScanner had the heating core pegged at 5.6kW most of the time, until we lowered the fan speed, and with the sun out, it had a chance to catch up after a couple hours on the road.

To be honest, I had the same issue with my Focus at those temperatures; most cars can't keep temperatures up on the highway. At least in the Mach-E, once we would slow down in town, it had a chance to warm up again; it also had no issue warming up in the morning, which was great; however, I wish the climate logic would take care of that itself, as it clearly knows it can't keep up with the coolant temperature.

Thanks for the detailed example.

I'm glad others such as yourself agree at how unsafe the programming and behavior of the mach-e has become over time with progressive OTA updates.

I am totally with you, you can't display charge/range you don't have full access to without at least some kind of indicator that you will be limited at that point. Or as you said, adjust the SOC to reflect changing variables, it would then play nicely with routing, charger navigation prompts etc.

On the same note though, having gotten so used to avoiding 30%SOC in winter over the past year like so many others, if they make that change, they would have to be VERY clear on what they are doing. They'd probably be better off undoing whatever change caused the turtle mode to start happening at 30%. As many have said, the original programming was the best.

 

[GarageWarrior2023]

I wish your battery temperature data was inputted. Then again, an app such as car scanner pro and ORB 2 reader is needed.

I'm not sure if I will be able to replicate the event, normally it get it at 30%. this was the only time I have ever had it at 40%. I do have an obd2 and carscanner. I just don't track every trip, I usually have specific trips I plan to track for various data I'm interested in. I'll try to pick a similar day and conditions and actually track that one. might be a couple of weeks, temperatures aren't going to be below -25 for a few days.

 

[Shayne]

Thanks for the detailed example.

I'm glad others such as yourself agree at how unsafe the programming and behavior of the mach-e has become over time with progressive OTA updates.

I am totally with you, you can't display charge/range you don't have full access to without at least some kind of indicator that you will be limited at that point. Or as you said, adjust the SOC to reflect changing variables, it would then play nicely with routing, charger navigation prompts etc.

On the same note though, having gotten so used to avoiding 30%SOC in winter over the past year like so many others, if they make that change, they would have to be VERY clear on what they are doing. They'd probably be better off undoing whatever change caused the turtle mode to start happening at 30%. As many have said, the original programming was the best.

Have you tried putting on a toque and turning hvac off? Turtle mode should disappear after 10 15 minutes. Right around the time the facial hair turns frosted frozen white. It would be nice to have a bit of heat in the cabin as all or nothing is pretty extreme.

 

[Shayne]

I think NiMH and lead acid are fine for below freezing. I know you can add cobalt to lithium batteries to give them better characteristics at low temperatures, but I doubt anything would work at -17c. Plus, cobalt isn't cheap and is a highly contested mineral, so I don't know how much of it is in our packs.

Tesla definitely doesn't have any secret sauce because their cars spend enormous amounts of energy (compared to us) keeping the pack at a happy temperature.

When the old plate 12V's (H2O) froze it would crack the plates and were not much good after. Of course they do not freeze at very low temps if at a high acid concentration (SOC). I was of the understanding that you should never charge any frozen battery. Question is at what temp do they freeze and what are the recommendation when charging? Hard to find info on the batteries that are in this vehicle. Secrets.

 

[ChehRob]

One thing fossil fuels can do efficiently is heat. I had a 5000 BTU Wallace in my small cruising boat. A gallon of diesel can produce 10K BTUs for almost 14 hours. Could such a unit address EV problems in extremely cold weather?

 

[MrFord]

One thing fossil fuels can do efficiently is heat. I had a 5000 BTU Wallace in my small cruising boat. A gallon of diesel can produce 10K BTUs for almost 14 hours. Could such a unit address EV problems in extremely cold weather?

They do, but only to a point. at -40c, very few ICE cars can manage to actually keep the coolant warm enough to heat up the cabin on the highway. You will actually see the temp gauge go down on the road. I think that in this case, resistive heating is the better solution, and it did work pretty good considering the conditions.

I'm not sure if the heat pump models will be able to improve in any way on this; I think they still come with a backup resistive heating core too?

 

[MrFord]

Thanks for the detailed example.

I'm glad others such as yourself agree at how unsafe the programming and behavior of the mach-e has become over time with progressive OTA updates.

I am totally with you, you can't display charge/range you don't have full access to without at least some kind of indicator that you will be limited at that point. Or as you said, adjust the SOC to reflect changing variables, it would then play nicely with routing, charger navigation prompts etc.

On the same note though, having gotten so used to avoiding 30%SOC in winter over the past year like so many others, if they make that change, they would have to be VERY clear on what they are doing. They'd probably be better off undoing whatever change caused the turtle mode to start happening at 30%. As many have said, the original programming was the best.

If you leave the house after being plugged in a 30A charger and precondition before, it should not be an issue, as the pack will keep it's temperature above freezing long enough to have to charge again; the issue seems to happen only if you let the pack go cold overnight (no charging or 110V) and hit the road right away.

It can clearly run fine, as long as you are about 30% or so; if it had that buffer grayed out, it would redirect you to a DC charger, which would at least be able to run the coolant heating while charging. It won't charge very fast, but as it will free up that 30% buffer, it will add range faster than the SoC % and for most users, it will look like a decent charging session, even if a bit early. Again, communication is key here; inform the user of the reason for the reduced battery capacity and the need for the charging stop, and how to prevent it if possible next time.

Point in case, once we got out of turtle mode, I was able to run the battery down to 6%, with external temperature of around -25c, with no turtle mode at all; t really is dependent on the battery temperature and not the external conditions for that. As long as the battery was around 0c, the car was happy.

If it had a battery temperature gauge (like all ICE cars and the Lightning I think), it would be pretty easy to understand where it would be, without relying on an OBD reader. Remote start should also take care of at least warming up the battery to a minimum coolant temperature as it warms up the cabin; yes, planned departure is great, but it is pretty ridiculous that it won't do that because I manually remote start the car. It will take a couple extra minutes and some battery, but 99% of users would now even notice, and by the time you get in the car, it's already warm anyway.

Sponsored