AC charge speed derate at 92%

[RLXXI]

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

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

That's something definitely different than what I'm seeing, mine creeps up to 100 and hangs there a little bit and slowly drops as I drive. Once I thought I saw it dip to 99 right away. Sounds like you may have a battery issue.

Think I'll pop outside for some readings.

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[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.

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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.

 

[Heliian]

Amps and kw are 2 different things.

I think people also tend to overanalyze their obd scanner readings.

 

[chriserx]

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............

Excellent, answered my remaining questions about the PTC, including both how it looks at the charger/ford app (just looks like charging) and amp cost at the charger (25-30, daymmm)

 

[chl]

So if we assume the BMS for the HVB is doing its job when it derated the current, what could the reasons be?

As mentioned above battery temperature could be a reason - if the battery cooling system is not working effectively that could be an issue I imagine.

A poor SOH degraded battery - the OP's battery reportedly has a 98% SOH so that doesn't seem to be a factor.

Cell imbalance - the BMS might be trying to balance cells/modules and if the imbalance if high, that could be a reason, again it's an 'I guess.'

The OP shows a 4.76% module variation / imbalance. I am not 100% positive, but that seems to me could indicate a bad battery module?

The charge curve for an EV battery up to 80% SOC or so is a constant current curve, the EVSE delivering max current (controlling the voltage).

Above that level it switches to a constant voltage method and the current reduces.

That change is most dramatic in DC Fast charging where high initial currents are being used, but it is also normal in AC charging though may not be very noticeable.

The OP has a very noticeable drop in current, so that does seems to indicate a battery problem.

I suppose it could also be the BMS has an issue, but with the module imbalance noted, not as likely?

Just my guesses.

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