Turtle Mode With ~30% Left (Cold Weather Warning)

[Mach-Lee]

Do we (you) know for certain that there was a software change that is causing these turtle modes to happen or are we just assuming it must be, based on the reported increase of turtle modes?

We don’t know. But based on the lack of reports about this last year from Canadians, it’s probably a change. I also had a drive last year in almost identical conditions where it didn’t happen.

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[athomas43]

Lol the timing. I experienced this for the first time two days ago and was so confused. I went from driving 80+ mph to 65 max

 

[PicoR]

This past fall, I let the SOC get down around 30%. Temps were warm and the car suddenly went into turtle mode. As the car was slowing down to a crawl with full throttle, I let up on the accelerator and press down to the floor and turtle mode went away and car accelerated. It's never happened since. 2023 Premium AWD/EXT

 

[Shayne]

Where are you getting that you can only charge it to 80%?

You mean the DCFC brick wall of death. Think most are aware of this.

 

[KevinS]

You mean the DCFC brick wall of death. Think most are aware of this.

Say what? Charging speed slows down but you can certainly continue past that point if you have to.

 

[Shayne]

Say what? Charging speed slows down but you can certainly continue past that point if you have to.

I guess with a 30% turtle mode we may need to sit there and wait.

 

[kennan]

Another data point in favor of this being from a recent software update: Late last year, I got my first turtle (orange only) when I was stuck waiting in line at an EA station in subzero temps, and the turtle only showed up then at 3 or 4 percent SOC. Nothing at all like what people are seeing now with 30% SOC in similar conditions.

 

[bbulkow]

you don't need ForeScan.... the CarScanner app does a great job and enables 'custom' dashboard on your phone. Unfortunately not on the center console, but maybe someday.

I though my post was correct. You need forescan and a high quality dongle to enable on the display screen, you can use phone or tablet and app and low quality dongle to see the info on another screen, which you also say, so we agree

 

[GarageWarrior2023]

Has anyone gotten any feedback on this issue? The last I heard about this, an internal investigation was being done at Ford. But nothing has come to light since.....

Personally I'd like to know which OTA caused the issue, and then which OTA will be released (and when) to resolve it.

 

[MightyMike]

So i did a little math, and assuming I am reasonably close, to heat a 750kg battery (roughly what I estimate it to be) from 0 to 30 degrees Celsius, assuming it has the same specific heat as steel (which is probably not right), and assuming a 100% efficient 5kw heater (which is definitely not correct), takes 35 minutes.

I think that is an unreasonably small number (like it is likely higher than that). If you are going down the highway, bleeding heat due to lack of insulation, and using a fraction of the heater to add heat back to the battery, there is no way you will maintain battery temps.

If I had to venture a guess, I'd say that Ford decided to optimize the battery for high temperatures, rather than low ones. In other words, if you are going to protect the battery, make sure it doesn't melt in Phoenix, even if that means it might have some under-performance in the winter.

 

[Mach-Lee]

So i did a little math, and assuming I am reasonably close, to heat a 750kg battery (roughly what I estimate it to be) from 0 to 30 degrees Celsius, assuming it has the same specific heat as steel (which is probably not right), and assuming a 100% efficient 5kw heater (which is definitely not correct), takes 35 minutes.

I think that is an unreasonably small number (like it is likely higher than that). If you are going down the highway, bleeding heat due to lack of insulation, and using a fraction of the heater to add heat back to the battery, there is no way you will maintain battery temps.

If I had to venture a guess, I'd say that Ford decided to optimize the battery for high temperatures, rather than low ones. In other words, if you are going to protect the battery, make sure it doesn't melt in Phoenix, even if that means it might have some under-performance in the winter.

FYI I've previously determined the heat capacity of the extended battery to be 0.18 kWh/ºC or 630 kJ/ºC. Therefore 0ºC to 30ºC would take about an hour at full output. This roughly corresponds to literature values of 1040 J/kg·K for NMC batteries (vs. 451 J/kg·K for iron).

If the pack were insulated and charging waste heat was scavenged, it would stay around roughly 10ºC or higher all the time, even when parked outside overnight. So it would heat up much faster for DC charging.

Omitting the insulation doesn't make much sense for Arizona either, parking on hot 180ºF asphalt will heat up the battery pack more than if it had bottom insulation. Battery could overheat if parked unplugged. I think they just omitted it to be cheap.

 

[GarageWarrior2023]

Omitting the insulation doesn't make much sense for Arizona either, parking on hot 180ºF asphalt will heat up the battery pack more than if it had bottom insulation. Battery could overheat if parked unplugged. I think they just omitted it to be cheap.

I completely agree with @Mach-Lee

Take a look at this video below. I firmly believe that insulation is the missing component in both hot and cold weather battery longevity and performance. Creating a constant narrow battery temperature band and holding it all year round for predictable/dependable range across seasons. I think we need to stop viewing the bottom of the battery as a radiator.....EV's have a radiator already and they liquid heat/cool the pack. When you try to cool the pack actively and have heat below the cold plate with no thermal break, you are making the AC compressor work harder than it has to.

 

[GarageWarrior2023]

I had a chance to do some testing at -20c today at low SOC with car scanner hooked up on my drive home. I hadn't had car scanner connected when it happened to my other Mach-e at -27 the first time (same weekend it happened to @Mach-Lee)

I think I have a better idea of what value was changed in the update. I believe they lowered an amperage limit that dictates when the red turtle mode kicks in. From there, turtle mode is a progressive scale to keep amperage below a certain value.

From what I can see it seems like the red turtle mode is based on an amperage limit (generally speaking....hot or cold weather). As voltage drops amperage increases to maintain the same output.

Two things will cause voltage to drop:
1. SOC, the lower your SOC the lower the voltage of the pack is
2. Temperature, the colder your pack is the lower the voltage is

This time around, my battery was not as cold as it was the last time. my pack was at only -2c. I got to 28%SOC before getting amber turtle which very slightly reduced power. My battery temp maintained while I continued at highway speeds. as I passed 25%SOC I got the red turtle mode and my speed started to get clipped from 105km/h down to about 100km/h, and then to about 98km/h as I got to about 20%SOC.

what I noticed this time was I did not get the cold battery warning in conjunction with the red turtle mode like last time. There does not appear to be any stopping of heating or anything of that nature at the 30% mark. I think it's all based on an amperage limit and cold battery contributes along with low SOC.

Since I didn't have the cold battery warning this time, if I were to slow down or stop for a moment or two then start up again, I could get back to only an amber turtle. it was only at highway speeds (or over a certain speed causing my amperage draw to hit the threshold) that it would kick back into red turtle mode.

So long story short, I think Ford reduced an amperage draw threshold used for the initiation of the red turtle mode protocol. Before I would assume they had a higher threshold and as such we were not seeing this issue happen before in lower temperatures at low SOC.

Question still remains.......when will Ford reverse this change so we can return to original full function again in the winter.......

 

[Mach-Lee]

I had a chance to do some testing at -20c today at low SOC with car scanner hooked up on my drive home. I hadn't had car scanner connected when it happened to my other Mach-e at -27 the first time (same weekend it happened to @Mach-Lee)

I think I have a better idea of what value was changed in the update. I believe they lowered an amperage limit that dictates when the red turtle mode kicks in. From there, turtle mode is a progressive scale to keep amperage below a certain value.

From what I can see it seems like the red turtle mode is based on an amperage limit (generally speaking....hot or cold weather). As voltage drops amperage increases to maintain the same output.

Two things will cause voltage to drop:
1. SOC, the lower your SOC the lower the voltage of the pack is
2. Temperature, the colder your pack is the lower the voltage is

This time around, my battery was not as cold as it was the last time. my pack was at only -2c. I got to 28%SOC before getting amber turtle which very slightly reduced power. My battery temp maintained while I continued at highway speeds. as I passed 25%SOC I got the red turtle mode and my speed started to get clipped from 105km/h down to about 100km/h, and then to about 98km/h as I got to about 20%SOC.

what I noticed this time was I did not get the cold battery warning in conjunction with the red turtle mode like last time. There does not appear to be any stopping of heating or anything of that nature at the 30% mark. I think it's all based on an amperage limit and cold battery contributes along with low SOC.

Since I didn't have the cold battery warning this time, if I were to slow down or stop for a moment or two then start up again, I could get back to only an amber turtle. it was only at highway speeds (or over a certain speed causing my amperage draw to hit the threshold) that it would kick back into red turtle mode.

So long story short, I think Ford reduced an amperage draw threshold used for the initiation of the red turtle mode protocol. Before I would assume they had a higher threshold and as such we were not seeing this issue happen before in lower temperatures at low SOC.

Question still remains.......when will Ford reverse this change so we can return to original full function again in the winter.......

Turtle mode happened again at 28% eh?

Yes it's an amperage limit that decreases with SoC based on the battery temp. When the amp limit crosses particular thresholds then you get yellow or red turtle indications. It seems to be designed to limit voltage sag on the pack. I think if you slow down or stop for a while it allows the pack to warm up a couple degrees and raises the amperage limit.

It does seem like a recent software change, but in my opinion they were too conservative with it. The pack can handle more voltage sag then they're allowing safely.

Did you get 24-PU0102-CHG-SUFX yet? That may change things. Really cold temps are done for the season here, so I can't do further testing.

 

[GarageWarrior2023]

It does seem like a recent software change, but in my opinion they were too conservative with it. The pack can handle more voltage sag then they're allowing safely.

Did you get 24-PU0102-CHG-SUFX yet? That may change things. Really cold temps are done for the season here, so I can't do further testing.

I agree with you. It can handle more and has successfully prior. I prefer the original behavior. more usable, safer and more predictable than what we get currently.

I have not received 24-PU0102-CHG-SUFX on either Mach-E yet. Do you know what this update is supposed to do and/or what modules it's impacting?

I most likely won't see this update before temps drop either.......I'm usually a bit behind everyone else on these forums getting the updates.

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