AC charge speed derate at 92%

[2023 xlt]

Hi guys,
First post thanks ahead of time!

Im experiencing an ac charge derate at 90% really slows at 92%.
Went to charge to 100% last week for a trip and the truck started derating at 92%. Went from 6.8a to 5a at 90% down to 1.6a by 92%.

I was using my 32a charger at work anker brand. I figured the evse was acting weird so when i got home i plugged into my 40a charge point flex and experienced the same issue. Truck is basically derated to level 1 charging after 92%.

Truck dc fast charged to 80% on my trip just fine.
When i got back home plugged in and it pulled the full 40a until it hit 90% again and started to derate until level 1 speeds at 92%.

My cell voltage variation seems higher than I remember. Am i looking at a defective battery module?

Service is scheduled but they are a month out.

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[B177y]

Yeah, the module variation does look high. While you wait for your appointment, try charging to 100% when you can. See if the cell balancing once it nears 100% does anything.

 

[2023 xlt]

Yeah, the module variation does look high. While you wait for your appointment, try charging to 100% when you can. See if the cell balancing once it nears 100% does anything.

Sounds good im at 90% right now will see if it gets to 100% by the time i leave work at 3pm!

 

[RLXXI]

Normal operation. Once you hit 80% it starts derating and keeps derating until you hit 100%

 

[TaxmanHog]

Normal operation. Once you hit 80% it starts derating and keeps derating until you hit 100%

True for DCFC, but not AC charging, the cliff occurs around 98%

 

[B177y]

Normal operation. Once you hit 80% it starts derating and keeps derating until you hit 100%

When you're using DCFC, yes it slows after 80%. AC charging holds it's full speed until 99% or so. That last 1% can take 1-2 hours when the cell balancing happens and the AC input drops considerably, like to 1 amp or less.

 

[RLXXI]

True for DCFC, but not AC charging, the cliff occurs around 98%

I watched it derate in real time using my FCSP. I don't recall when exactly it started It may have been in the 90's but it dropped 3 times before it hit 100%.

 

[RLXXI]

When you're using DCFC, yes it slows after 80%. AC charging holds it's full speed until 99% or so. That last 1% can take 1-2 hours when the cell balancing happens and the AC input drops considerably, like to 1 amp or less.

Perhaps for your truck but not mine, I watched it derate in real time.

 

[chriserx]

Hi guys,
First post thanks ahead of time!

Im experiencing an ac charge derate at 90% really slows at 92%.
Went to charge to 100% last week for a trip and the truck started derating at 92%. Went from 6.8a to 5a at 90% down to 1.6a by 92%.

I was using my 32a charger at work anker brand. I figured the evse was acting weird so when i got home i plugged into my 40a charge point flex and experienced the same issue. Truck is basically derated to level 1 charging after 92%.

Truck dc fast charged to 80% on my trip just fine.
When i got back home plugged in and it pulled the full 40a until it hit 90% again and started to derate until level 1 speeds at 92%.

My cell voltage variation seems higher than I remember. Am i looking at a defective battery module?

Service is scheduled but they are a month out.

As others noted, the module variation seems on the higher side of 'normal'. What was your SoC in the screenshot? You said it was effectively level 1 but you're seemingly pulling about 17-18 amps at 240v. What's the lowest kW you're pulling? I'm inclined to think it's balancing the cells.

 

[2023 xlt]

As others noted, the module variation seems on the higher side of 'normal'. What was your SoC in the screenshot? You said it was effectively level 1 but you're seemingly pulling about 17-18 amps at 240v. What's the lowest kW you're pulling? I'm inclined to think it's balancing the cells.

Screenshot soc was 91% started to derate after i hit 90%

Im currently at 92% and its down to 4.9
Was pulling 6.8 at 90%

Time on charge looks weird
because i pulled into shop at 88% it charged to 90 and was shut off for a couple hrs before i restarted

 

[RLXXI]

Screenshot soc was 91% started to derate after i hit 90%

Im currently at 92% and its down to 4.9
Was pulling 6.8 at 90%

Time on charge looks weird
because i pulled into shop at 88% it charged to 90 and was shut off for a couple hrs before i restarted

Just posting a reply so you know you're not crazy, the one time I paid attention while mine was charging did the same thing. I don't remember exactly when it started derating but it dropped at least 3 times before it hit 100% .

Fairly new FCSP as well, 7 months in use.

 

[chriserx]

Screenshot soc was 91% started to derate after i hit 90%

Im currently at 92% and its down to 4.9
Was pulling 6.8 at 90%

Time on charge looks weird
because i pulled into shop at 88% it charged to 90 and was shut off for a couple hrs before i restarted

Taken at more or less the same time? Ford app says charge rate is 4.9kW OBD says 4.2kW and to battery says 4.08kW. It hasn't gotten cold enough since I got data logging enabled but a charging efficiency of 83% is pretty low so something is going on. Someone with more data may be able to tell you if it's conditioning the battery with those numbers, but hopefully it's just balancing the cells and a couple full L2 charges gets you running right.

 

[2023 xlt]

Update truck went from 95% to 100% instantly and said charge complete.

Showing only 118kw usable and actual battery SOC at 87%

 

[bmwhitetx]

Update truck went from 95% to 100% instantly and said charge complete.

Showing only 118kw usable and actual battery SOC at 87%

I think you and I are in the same boat. If you start the truck, see if the SOC instantly drops to 90% or less.

I started getting the same behavior - charging slowed, then instantly 100, but dropped back <90 when truck started. App reports 100% but range number nowhere near 100% value.

See my adventure here. In particular look at the SSM in post 17.

 

[chriserx]

Sure sounds like it was gonna link it myself. How often did y'all charge to 100% before this occured.

I think you and I are in the same boat. If you start the truck, see if the SOC instantly drops to 90% or less.

I started getting the same behavior - charging slowed, then instantly 100, but dropped back <90 when truck started. App reports 100% but range number nowhere near 100% value.

See my adventure here. In particular look at the SSM in post 17.

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