Winter Range Loss in Mach-E -- a more detailed look with some measurements

[awp0]

I was disappointed at first. If I was paying for power (mine is free from work) it would have bothered me more. I am sure Tesla does the same. Knowing the car was reporting more efficiency that in reality was a surprise. once I figured it out, it was not the end of the world. That’s part of the reason for the low Mach E winter range. But all EVs lose winter range and Ford does actually tell you with the GOM estimates. I found my GOM was pretty accurate , within 10 miles during the winter….What’s 10%….

Thanks. I'm excited to dig in and gather some data and learn more about this.

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[mkhuffman]

Question: I would have assumed the difference between "HVB SOC" and "HVB SOC Display" is related to the battery buffer. Yes/no?

Yes, that is exactly it. SoC is on full battery capacity - 91 kWh (or less, if your battery is degraded due to age and/or cold temperatures).

Edit:
Sorry I meant 99 kWh, not 91. 91 kWh is the available capacity (used for SoCD), 99 is full capacity (less with cold/age losses) used for SoC. Not sure what I was thinking when I typed that.

 

[Nklem]

I guess I should not have wished for it. 7F Wed Night and -16F forecasted for Friday night. It looks like I will have to plug in and monitor the battery treatment and kWh it draws as well as charge to 100% and monitor the capacity loss due to cold. I will also be doing a -10 to 75F Cabin Heating test against a Mach E Friday night or Saturday AM for Youtube.

Well 1F and plugged in. No battery heating in the Ioniq 5 after charging to 100%. and 100% was still 96.5% of full capacity available. I actually had nearly 200 miles of range at that temp. So I will plug in at -15 lf tomorrow night and see if it heats, but from what I can tell, Hyundai manages the cold pretty well with still over 71 kWh available from a 75 kWh battery at 1F ambient, 15F battery. I also let it cold soak for 24 hours the next day and still just 94.5% of actual capacity available but still 15F.. I was able to test heating in this cold. 1F to 72F inside was under 20 mins.

 

[Nklem]

Well 1F and plugged in. No battery heating in the Ioniq 5 after charging to 100%. and 100% was still 96.5% of full capacity available. I actually had nearly 200 miles of range at that temp. So I will plug in at -15 lf tomorrow night and see if it heats, but from what I can tell, Hyundai manages the cold pretty well with still over 71 kWh available from a 75 kWh battery at 1F ambient, 15F battery. I also let it cold soak for 24 hours the next day and still just 94.5% of actual capacity available but still 15F.. I was able to test heating in this cold. 1F to 72F inside was under 20 mins.

-14 last night and no battery heating either. Still have over 95% of the battery capacity. I took a 50 mile trip to test heating and nothing for battery care… but I was toasty..

 

[awp0]

So last night was the coldest my MME has experienced. It was plugged in (level 2) outside overnight in -10F to -15F outdoor temps, starting at about 9:30pm. I noticed FordPass has had the car in "Preparing For Drive" status since I plugged it in last night, but Scheduled Departure is turned OFF altogether. I can also see in my EVSE logs and in my circuit monitor that the car started charging sessions twice on its own overnight, each lasting about 25 minutes. One at about 12:45am and another at about 5:00am. Anyone know if this is designed to warm/protect the battery, or if it's just trying to keep the battery at a target SOC?

 

[Nklem]

So last night was the coldest my MME has experienced. It was plugged in (level 2) outside overnight in -10F to -15F outdoor temps, starting at about 9:30pm. I noticed FordPass has had the car in "Preparing For Drive" status since I plugged it in last night, but Scheduled Departure is turned OFF altogether. I can also see in my EVSE logs and in my circuit monitor that the car started charging sessions twice on its own overnight, each lasting about 25 minutes. One at about 12:45am and another at about 5:00am. Anyone know if this is designed to warm/protect the battery, or if it's just trying to keep the battery at a target SOC?

It’s keeping the battery warm. Mine used to do it.

 

[awp0]

It’s keeping the battery warm. Mine used to do it.

Cool, thank you!

 

[Guss-E 2021]

It was - 12°F (-28°F with windchill) this morning. Now it is - 1°F. First time driving in truly cold weather. Short drives (<10 miles). I felt the car warmed up to a comfortable temp quickly enough. Heated seats and steering wheel were very helpful. I did set a departure time for my morning appointment but it didn't appear to kick on. That normally works fine. Leaving my appointment, I started the car from my app. I do wish you could set a one-time departure. It seems you can only set a schedule or nothing. My understanding is that using a departure time will prompt the car to warm up the battery prior to leaving as well as the cabin.

I did not pay much attention to miles/kW because my drive times were too short.

 

[Electric Goat]

So since capacity is being pulled down in cold temps, is it cool to just charge the car to 95%-100% every day in the winter and dial back daily charging to 90% in the summer?

 

[mkhuffman]

So since capacity is being pulled down in cold temps, is it cool to just charge the car to 95%-100% every day in the winter and dial back daily charging to 90% in the summer?

I think the charge level should be what you need, even in the summer. If 90% in the winter still gives you enough range, just keep doing that. If you need more range, charge higher.

A related question: if my battery SoH is 92% and I charge to 100%, isn't that like charging to 92%? I don't know the answer.

 

[Rjm]

All the calculation above are interesting, but recently Ford updated the Software and said they improved the accuracy of the mileage. Last night I charged my Mach E to 90 % and the Range read 258 Miles and the odometer read 12079.8. I made two trips in the morning and when I returned home the odometer read 12110.3 for a total of 30.5 miles. The new Range reading was 202 miles for a loss of 56 miles, with 76% left on the battery. So I drove a total of 30.5 miles and the figures said I used 56 miles (and 14%) worth of battery charge. Does not give me much confidence in the figures if I am planning to take a long trip. Whoever created the new algorithm for Ford should look for a new job!!

 

[RedDragon]

This may be a dumb question but I will ask it anyway, as I'm having trouble really understanding what conceptually what having a lower battery capacity at cold temps actually means.

Let's say you were to charge your car to 100 percent in a heated garage at 50 degrees ambient temp. then you immediately go outside and park it outside at 0 degrees ambient temp and allow the car to sit there for 2 days, while being unplugged. Since the battery capacity shrinks in the cold, would this scenario be damaging to the pack? What happens to the extra kwhs stored in the pack?

Again this may be a completely dumb question but it will probably help me understand this a little better.

 

[alexgorod]

My understanding is that using a departure time will prompt the car to warm up the battery prior to leaving as well as the cabin.

My understanding is that the battery gets warmed up only when the car is plugged in. If not - it only warms up the cabin, so basically the same as after starting it remotely.

 

[Mach-Lee]

Let's say you were to charge your car to 100 percent in a heated garage at 50 degrees ambient temp. then you immediately go outside and park it outside at 0 degrees ambient temp and allow the car to sit there for 2 days, while being unplugged. Since the battery capacity shrinks in the cold, would this scenario be damaging to the pack? What happens to the extra kwhs stored in the pack?

When the pack cools down, the extra capacity gets "trapped" in the pack. It will not damage the pack, you just can't make use of it until the pack is warm again. As soon as the pack warms up you get the capacity back, so it's not permanent loss, just temperature-dependent loss.

That's why when you warm up the pack, the kWh available reading increases even though you aren't charging it. You're unlocking more capacity as you warm it up.

Let's say you run your pack down to 0% when it's 0ºF. If you park in a heated garage overnight, you might come back and find you now have 10% battery even though you didn't charge. The heat unlocked it.

 

[SpaceEVDriver]

This may be a dumb question but I will ask it anyway, as I'm having trouble really understanding what conceptually what having a lower battery capacity at cold temps actually means.

Let's say you were to charge your car to 100 percent in a heated garage at 50 degrees ambient temp. then you immediately go outside and park it outside at 0 degrees ambient temp and allow the car to sit there for 2 days, while being unplugged. Since the battery capacity shrinks in the cold, would this scenario be damaging to the pack? What happens to the extra kwhs stored in the pack?

Again this may be a completely dumb question but it will probably help me understand this a little better.

It's not a dumb question.

The answer is no, there's no immediate damage to the pack.

The way the pack's capacity decreases in the cold is best understood by an analogy to a bucket of water that partially freezes in the cold. The size of the bucket is the same as always, but you can only pour out the water that remains liquid.

What is actually happening is that low temperatures reduce the rate of the chemical reactions that provide the electrochemical potential energy. But there's no damage done to the battery if the temperatures are low for a short period of time and if there's no massive current into or out of the battery while it's cold.

This lowered chemical reaction rate (lower capacity) is separate from the increased internal resistance that comes from lower temperatures. And also separate from the increased energy used to heat the cabin.

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