GOM Irregularities

[Rtashiro]

I have had my truck for a little over 2 years now. Purchased brand new 2023 Lariate ER. I have a daily charge limit set to 80%. I went to leave for a short drive the other day and my SOC went down fairly quickly from 80 in the garage to 78 by the time I reversed 50 feet which I thought was odd. It continued to go down to around 75 by the time I had driven a block or two. So I started watching it carefully and the SOC started then raising back up slowly. By the time I got to my destination approximately 6 miles away the SOC was 81%. To preface the terrain is flat. Minimal to no regen was happening. on my way back in did go back down but slowly. I arrived back in my garage with 79%. Today I had another short trip and the numbers were not quite as extreme but was still odd SOC behaviour. Clearly there is something happening with the BMS but I was wondering if this needs to be calibrated and if so how? Anyone else have similar behaviour before?

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[TaxmanHog]

What & when was your your last OTA?
Seen in the Sync screen and on Ford.COM to see the date of install.

 

[Maquis]

That happens when cells get unbalanced. Charging to 100% occasionally helps, it sounds like you never do that. The last % or so may take a couple of hours while balancing occurs.

Theres also a procedure you can follow that will help balance cells and calibrate the BMS:
https://www.macheforum.com/site/threads/hv-battery-calibration-procedure.23815/

 

[Rtashiro]

What & when was your your last OTA?
Seen in the Sync screen and on Ford.COM to see the date of install.

Last update was recent feb 5

 

[chriserx]

That happens when cells get unbalanced. Charging to 100% occasionally helps, it sounds like you never do that. The last % or so may take a couple of hours while balancing occurs.

Theres also a procedure you can follow that will help balance cells and calibrated the BMS:
https://www.macheforum.com/site/threads/hv-battery-calibration-procedure.23815/

Agree completely, at the very least charge to 100% a few times, or follow the guide for better precision.

 

[mr.Magoo]

It's also winter in Manitoba.

The SoC in the cluster / app is what is referred to as "Displayed SoC", no one really knows (well, except Ford - and that's a maybe) how that works, but it takes a bunch of factors into account and then presents you with a SoC.

Temperature is an important factor, so if it had been sitting for a while between charging and going for your drive you might see a sudden drop, and similarly, if the day warms up quite a bit you could see a gain from that.

I'd reccomend getting an OBD dongle, it's a fairly inexpensive investment and will give you a lot of knowledge / understanding about the inner workings of your truck, you can nerd out completely like myself and @Firn , or you can just take a look at the essentials like battery temperature, state of health and module variation and sleep soundly at night knowing that everything is OK.

 

[Heliian]

It's cold. It's normal.

Keep truck plugged in and use departure times for optimal accuracy.

 

[Rtashiro]

It's also winter in Manitoba.

The SoC in the cluster / app is what is referred to as "Displayed SoC", no one really knows (well, except Ford - and that's a maybe) how that works, but it takes a bunch of factors into account and then presents you with a SoC.

Temperature is an important factor, so if it had been sitting for a while between charging and going for your drive you might see a sudden drop, and similarly, if the day warms up quite a bit you could see a gain from that.

I'd reccomend getting an OBD dongle, it's a fairly inexpensive investment and will give you a lot of knowledge / understanding about the inner workings of your truck, you can nerd out completely like myself and @Firn , or you can just take a look at the essentials like battery temperature, state of health and module variation and sleep soundly at night knowing that everything is OK.

I have a dongle and paid version of car scanner. I don’t really get into the individual cell voltage stuff though.

 

[Jiji]

I'll guess your battery temperature is changing. I have found that the reported Energy to Empty value changes with the battery temperature and the Distance to Empty (aka the GOM) is tied to this value.

For example, I recently charged overnight and the reported Energy to Empty at the end of the charging session was 123kWh at 53℉. Left a few hours later and the battery was cooled to 28℉ and the reported Energy to Empty was ~110kWh.

Or on a test trip made today to compare the Mach-E and Lightning, in freezing conditions I used 0.2kWh according to the Energy to Empty but in reality it was closer to 2.8kWh:

I had to give up using the Energy to Empty data point in the Lightning and calculate my own since it adjusts the reported energy content based on the battery temperature which it warmed by just a few degrees. I believe this is why you see jumps in the Distance to Empty/Energy to Empty after the battery haas been cooled or heated.

Compare to the Mach-E doing the same trip, battery temperature didn't measurably change (it was in an unheated garage) and Energy to Empty tracks closely with my calculated value:

Fun fact, the slope of the energy line picks up the elevation change very nicely:

 

[Alan168]

I agree with Jiji. I experience the same SOC changes during our cold winters. Can't recall seeing this in the summer. But I can't reliably remember that far back anymore!

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