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!

 

[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.

 

[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

 

[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.

 

[bmwhitetx]

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

My last charge to 100% was 10 months ago. Otherwise I charge to 85% so that is why I haven't noticed this issue.

In my first post of the thread I linked above, I saw a dramatic increase in the Module Voltage in early January. Before that my module variation was very low (checked monthly) so I don't think a 100% charge/rebalance would help IMHO.

With that said, I might start doing a 100% every month or two just to be safe??

I believe this is a bad battery module unrelated to charging practice. I previously had a module failed and replaced 2 years ago as well. The 2022's and 2023's seem to be prone to this.

 

[chriserx]

My last charge to 100% was 10 months ago. Otherwise I charge to 85% so that is why I haven't noticed this issue.

In my first post of the thread I linked above, I saw a dramatic increase in the Module Voltage in early January. Before that my module variation was very low (checked monthly) so I don't think a 100% charge/rebalance would help IMHO.

With that said, I might start doing a 100% every month or two just to be safe??

I believe this is a bad battery module unrelated to charging practice. I previously had a module failed and replaced 2 years ago as well. The 2022's and 2023's seem to be prone to this.

Yeah, I was just wondering. I just replaced my mobile cord for an OpenEVSE and removed the hard charge limit with a tapered charge to prevent it from ever sitting at any particular state of charge. We'll see how it works out. Best of luck to you both in the meanwhile!

 

[TaxmanHog]

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

Do you record log files with Car Scanner, if so look at the AC Charge COupler Temperature to see if it's spiking!!! Hope it's not as that would indicate a problem with either the port in the truck, since your seeing the same with your EVSE and the one at work, we can assume they aren't the problem.

Of course if you don't see abnormal temps, ie. 136 degrees is what I just experienced charging my truck from 83% to 95%, I never seen a derating during the entire process, then you might have other issues with the hardware of software on the truck.

------------------------------------------------------------------------------------

At the start of the process the HVB was very cold, so half the energy went to the PTC to warm it up as seen on second photo bottom graph 6.37 kW for warming (Cabin HVAC OFF) and 9.5kW was to charging (80 AMP EVSE), Emporia monitor showing 17.9 kW energy flow.

At this point 26 minutes the battery reached acceptable temp for full rate charging, PTC energy shut down to 0 kW, EVSE continued plugging along

I started monitoring the AC Charge Couple temperature on the bottom graph at this point (middle photo) input energy is consistent, no sign of derating.

Now at 94%, all is running fine, coupler temp 136.4 degrees, input energy stable

Hit the 95% point, it didn't auto stop because I had the truck "running" to keep the data feed going to car scanner with out interruption, I manually shut it down, ending results.

Charging statistics for the fun of it............

 

[2023 xlt]

Do you record log files with Car Scanner, if so look at the AC Charge COupler Temperature to see if it's spiking!!! Hope it's not as that would indicate a problem with either the port in the truck, since your seeing the same with your EVSE and the one at work, we can assume they aren't the problem.

Of course if you don't see abnormal temps, ie. 136 degrees is what I just experienced charging my truck from 83% to 95%, I never seen a derating during the entire process, then you might have other issues with the hardware of software on the truck.

------------------------------------------------------------------------------------

At the start of the process the HVB was very cold, so half the energy went to the PTC to warm it up as seen on second photo bottom graph 6.37 kW for warming (Cabin HVAC OFF) and 9.5kW was to charging (80 AMP EVSE), Emporia monitor showing 17.9 kW energy flow.

At this point 26 minutes the battery reached acceptable temp for full rate charging, PTC energy shut down to 0 kW, EVSE continued plugging along

I started monitoring the AC Charge Couple temperature on the bottom graph at this point (middle photo) input energy is consistent, no sign of derating.

Now at 94%, all is running fine, coupler temp 136.4 degrees, input energy stable

Hit the 95% point, it didn't auto stop because I had the truck "running" to keep the data feed going to car scanner with out interruption, I manually shut it down, ending results.

Charging statistics for the fun of it............

I havent done that but its cool to see you can. Trucks scheduled for the shop in two weeks ill let them deal with it.
At this point its working great, just missing a little capacity.

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