Battery Percentage Display Adjusting?

[MariaM19]

Hello! Newbie here. Both in terms of posting on the forum and owning an EV (first time car owner too!). I did do multiple keyword searches to see if I could find my answer before posting, so my apologies if I'm repeating a past question. I bought a standard range MME from a dealership in mid-December. Due to a few reasons, I haven't gotten to drive it as much as I would have liked, but so far it's been a great experience.

I have a question about the display battery percentage (what I think is called the state of charge?). To be clear, I'm not referring to the GOM, but to the percentage of the battery displayed under the "whisper" driving mode. Is it normal for that to fluctuate or adjust sometimes? I recently charged to 100% for the first time since I bought the car, (I was going to take a ~160 mile roundtrip to see family but the trip got cancelled), and when I took it out for a shorter drive, the display battery percentage stayed at 100% for about an 8 mile trip at which I parked outside for a few hours. The drive was in cold weather ( in the 20s F), and when using the heat. I thought that was a bit strange. It eventually started to tick down normally on my return drive, and I got home with 97% battery. The next time I turned it on though, I barely pulled out of the driveway and it went from 97% to 94%.

Since then, things seemed fine with the battery display ticking down as it had before. Then yesterday I went to a friend's house for dinner, parked the car outside in cold weather (dropped from the 30s to the 20s while I was there), and when I turned on the car to leave, the percentage seemed a little lower than I expected at 77%, but I couldn't remember the exact number it had been when I pulled in. But then, before I moved the car, it adjusted upwards to 79%. So my question is, are these types of things (holding steady at 100% for a bit, adjusting downwards and also upwards a few percentage points) normal? Or should the displayed charge be fairly stable? I know the GOM goes all over the place, so I know to focus on the amount of charge rather than the range estimate, but I didn't know if I should expect some adjustments in the battery percentage display to occur, or if this is abnormal.

Any thoughts would be much appreciated, or if I somehow missed this being discussed earlier, I'd be appreciative of the previous discussion link! Thank you!

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[RickMachE]

Yes, that is normal. First, the percentage isn't shown to X decimal places. So, a 99% battery could be 99.44% or 98.51%. So popping up or down a percent or two can be explained by minor changes.

A 100% battery could very well have been 100.44%. Or, since we don't really know, over that since there is capacity above it and Ford hides that from us.

What you see is nothing to worry about. If you park at 20 degrees, and when you restart it's 60 degrees, it jumping a few points in the first few minutes is totally normal, and vice versa.

 

[Logal727]

Yes, that is normal. First, the percentage isn't shown to X decimal places. So, a 99% battery could be 99.44% or 98.51%. So popping up or down a percent or two can be explained by minor changes.

A 100% battery could very well have been 100.44%. Or, since we don't really know, over that since there is capacity above it and Ford hides that from us.

What you see is nothing to worry about. If you park at 20 degrees, and when you restart it's 60 degrees, it jumping a few points in the first few minutes is totally normal, and vice versa.

Also gotta take regen into account

 

[MariaM19]

Thanks so much! That makes sense, and I am glad to hear that as it did the same thing when I turned it on today, dropping from 76% to 74% when I pulled out of the driveway. So it sounds like a few percentage point adjustments are nothing to worry about, which is really helpful to know.

Since I'm still learning, may I ask what it means to take regen into account? I love to keep learning!

 

[Logal727]

Thanks so much! That makes sense, and I am glad to hear that as it did the same thing when I turned it on today, dropping from 76% to 74% when I pulled out of the driveway. So it sounds like a few percentage point adjustments are nothing to worry about, which is really helpful to know.

Since I'm still learning, may I ask what it means to take regen into account? I love to keep learning!

Every time you brake or slow down the vehicle, the car uses the electric motor to generate more power that goes back into the battery. Definitely recommend googling regenerative braking.

 

[RickMachE]

Every time you brake or slow down the vehicle, the car uses the electric motor to generate more power that goes back into the battery. Definitely recommend googling regenerative braking.

Right. Unfortunately there's no real way to see that on the Mach-E. However, if you were to drive up a mountain and then come down it, you'd see the battery increase in charge.

Most vehicles have a display that shows you when you are regenerating.

 

[MariaM19]

Got it, I knew that but hadn't realized how much it could affect the battery percentage. Too bad you can't see it somehow--that would be cool. Thank you for the extra info!

 

[Logal727]

Got it, I knew that but hadn't realized how much it could affect the battery percentage. Too bad you can't see it somehow--that would be cool. Thank you for the extra info!

Enjoy your car!!

 

[OH2AZ2OH]

Thanks so much! That makes sense, and I am glad to hear that as it did the same thing when I turned it on today, dropping from 76% to 74% when I pulled out of the driveway. So it sounds like a few percentage point adjustments are nothing to worry about, which is really helpful to know.

Since I'm still learning, may I ask what it means to take regen into account? I love to keep learning!

That seems maybe not typical, but not unusual either. Mine tends to move the other way, especially after a charge. I charge to 85%, and very often will see 86 or even 87% when I reach the end of my street. So far, I've only seen this with my home charger, the slower free chargers I've used haven't done that. I've not tried DCFC yet. I've seen drops after returning to the car after parking, too, but usually only on very cold days.

 

[timbop]

It's not just regen; computing the state (percentage) of charge requires precise measuring of the battery. Those measurements can be slightly affected by temperature changes, particularly below freezing. There is also the fact that the actual capacity of the battery decreases some when it gets really cold, and conversely can increase when it warms up. Similar things happen with the gas gauge on an ICE, but nobody notices because they are so imprecise in the first place.

Your car is fine

 

[EVnewbie3000]

Resuscitating this thread. For those of you who have owned the car a while, how long did it take the GOM to reach the range consistent with your avg power usage? I resetted it 3 weeks ago and it was showing 250mi on a full charge. It has been slowly going up but now stuck around 260 miles, even though I’m getting about 3.3-3.4mi/kwh on my awd ER premium (which calculates to about 300-310 miles on full charge).

i know the displayed number doesn’t really matter—this is more of an academic exercise for me and a game to get that estimated range to 300 then i can drive it like a maniac ?

 

[timbop]

Resuscitating this thread. For those of you who have owned the car a while, how long did it take the GOM to reach the range consistent with your avg power usage? I resetted it 3 weeks ago and it was showing 250mi on a full charge. It has been slowly going up but now stuck around 260 miles, even though I’m getting about 3.3-3.4mi/kwh on my awd ER premium (which calculates to about 300-310 miles on full charge).

i know the displayed number doesn’t really matter—this is more of an academic exercise for me and a game to get that estimated range to 300 then i can drive it like a maniac ?

"The fault is not in our stars GOM, but in ourselves"...

 

[Mach-Lee]

Resuscitating this thread. For those of you who have owned the car a while, how long did it take the GOM to reach the range consistent with your avg power usage? I resetted it 3 weeks ago and it was showing 250mi on a full charge. It has been slowly going up but now stuck around 260 miles, even though I’m getting about 3.3-3.4mi/kwh on my awd ER premium (which calculates to about 300-310 miles on full charge).

i know the displayed number doesn’t really matter—this is more of an academic exercise for me and a game to get that estimated range to 300 then i can drive it like a maniac ?

About 500 miles, but current temp is a large factor regardless of your driving history. It will considerably underestimate in that regard. Based on your efficiency and cold temps I would say your actual range is around 285 mi.

 

[EVnewbie3000]

You mean my true range, whihc mean the GOM would never get there during this season? FWIW my “ext temp” power useage is usually 8-9%, “driving” is 85-90%

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