Charging power vs state-of-charge (SOC)

[CivilJeep]

I found this article to be very interesting, particularly the graph that shows the Charging Power vs. SOC. The 150KW speed is really only available at the lowest SOC, which most people will rarely see. For all intents and purposes, a 75-100KW max is the best you're going to do, unless a Ford software update changes things. Apologies in advance if this has already been posted, but I thought it was some very informative info.

Ford Mustang Mach-E First Edition In-Depth DC Fast Charging Analysis (insideevs.com)

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[timbop]

Yes, it is absolutely true that the fastest rate is only held briefly and tapers off, but temperature significantly affects charging as well. If you nose around for @Mach-E VLOG 's, @ChasingCoral 's , or even @OutofSpecKyle's videos you'll see that the sustained rate is over 100kw to about 65% now that it's getting warmer.

 

[timbop]

Oh, and it is not just the Mach E. Every BEV except for the Audi e-tron has a similar charging curve that peaks early and tapers off as state of charge increases. I suspect the e-tron is going to have serious battery issues as it ages if a lot of DC fast charging is done.

 

[MachE911]

I've had my car charge at 106kW all the way up to 65% SOC and 90kW up to 80%. These curves seem really temperature dependent.

Looking at my charge log, I've done at EA stations:

1. 43% in 23 minutes (20%->63%) 98kWh average
2. 33% in 17 minutes (30%->63%) 102kWh average
3. 63% in 37 minutes (16%->79%) 90 kWh average
4. 36% in 17 minutes (32%->68%) 111kWh average

Kyle on the other hand charged 60% in 42 minutes (20%->80%) 75kWh average

 

[mixduptransistor]

These curves can be adjusted in OTA updates. Hopefully Ford will be collecting real-world battery statistics from cars and once they better understand the capabilities of the packs, and what is and isn't safe, they will both unlock the charging a bit more both in terms of when and how long it stays at higher power input as well as allowing it to stay at a higher power input above 80%

Also, hopefully they will be more comfortable about the buffer in the battery and unlock a little more of the battery that we don't have access to

 

[ChasingCoral]

Oh, and it is not just the Mach E. Every BEV except for the Audi e-tron has a similar charging curve that peaks early and tapers off as state of charge increases. I suspect the e-tron is going to have serious battery issues as it ages if a lot of DC fast charging is done.

Anyone know what Audi’s battery warranty is?

 

[GoGoGadgetMachE]

Anyone know what Audi’s battery warranty is?

I found 8 years/100,000 miles (pretty standard) fairly easily, but it's very hard to find that the warranty has no performance guarantee:

Battery warranty

so ... it can degrade massively apparently and still be "in spec."

explains the charging curve somewhat... they can absolutely trash the battery and say "sorry you're still charging, even though it's only to 20% of original" and that's too bad for you.

this by itself should be enough to stop anyone from buying the car. Leasing for three years where you don't give a damn what happens to the battery? sure.

 

[mixduptransistor]

explains the charging curve somewhat... they can absolutely trash the battery and say "sorry you're still charging, even though it's only to 20% of original" and that's too bad for you.

then what are they warranting? the only way to make a claim is if the battery stops working completely?

 

[GoGoGadgetMachE]

I found 8 years/100,000 miles (pretty standard) fairly easily, but it's very hard to find that the warranty has no performance guarantee:

Battery warranty

so ... it can degrade massively apparently and still be "in spec."

explains the charging curve somewhat... they can absolutely trash the battery and say "sorry you're still charging, even though it's only to 20% of original" and that's too bad for you.

this by itself should be enough to stop anyone from buying the car. Leasing for three years where you don't give a damn what happens to the battery? sure.

also it's amazing to me (*) that this isn't brought up every time someone praises the Audi charging curve, including so-called EV experts.

(*) not amazing at all, because most reviewers are actually kind of bad at reviewing

 

[ChasingCoral]

I found this article to be very interesting, particularly the graph that shows the Charging Power vs. SOC. The 150KW speed is really only available at the lowest SOC, which most people will rarely see. For all intents and purposes, a 75-100KW max is the best you're going to do, unless a Ford software update changes things. Apologies in advance if this has already been posted, but I thought it was some very informative info.

Ford Mustang Mach-E First Edition In-Depth DC Fast Charging Analysis (insideevs.com)

That's a nice article with some great curves. My two biggest take aways based on my DCFC experiences:
1. I think the biggest improvement can be found by increasing charging in those two long plateaus up to 40% and 40-80%.

2. They based their analysis off one charging curve and missed a couple of important things:
A. The initial peak to ~160kW is largely SOC independent. It's an important part of the Ford zap-and-dash strategy: go really fast for a short time to maximize the 10 minute charging while minimizing battery damage.
B. There is actually a third plateau between the up to 40% and the up to 80%. Their graph shows it briefly between 30-40%. I often found it was longer than that.

You can find my charging videos and some summaries in multiple posts within
https://www.macheforum.com/site/threads/my-travels-with-marlin-gb-fe-delivered.3298/

I have more information from my charging sessions I need to get around to posting there.

 

[GoGoGadgetMachE]

That's a nice article with some great curves.

careful now

 

[MightyJawa]

The sharp transitions in the charge curves seem to indicate that software is creating these “cliffs”. We know they are doing the 80% one but probably the 150 kW drop too. If it was strictly temperature or SOC related it would be more gradual. So that makes me hopeful that once they get the data they are looking for, the time at 150 kW will be increased.

 

[mixduptransistor]

The sharp transitions in the charge curves seem to indicate that software is creating these “cliffs”. We know they are doing the 80% one but probably the 150 kW drop too. If it was strictly temperature or SOC related it would be more gradual. So that makes me hopeful that once they get the data they are looking for, the time at 150 kW will be increased.

It's all software, even cars with more sane curves those curves are based on the rules and algorithms in the software on their battery management systems. The battery will physically take power until they explode, the battery itself can't limit incoming power

 

[sockmeister]

The sharp transitions in the charge curves seem to indicate that software is creating these “cliffs”. We know they are doing the 80% one but probably the 150 kW drop too. If it was strictly temperature or SOC related it would be more gradual. So that makes me hopeful that once they get the data they are looking for, the time at 150 kW will be increased.

Oh yes, without a doubt all of this is software controlled. That's why we're hoping for an OTA update to change it, once they have enough data.

 

[v8318cid]

Given that BEVs are still relatively new (mostly in terms of mass market adoption, not time on market), warranties are probably going to be all over the place. Nissan, for example, warranties the battery in the Leaf for 8yr/100k, but makes it clear that a warranty claim only applies if the battery health (WAG-ometer) gauge falls below 9 health bars. Even then, the warranty is only obligated to replace enough components/modules to restore the battery health to that level, not replace the entire pack. Obviously circumstances vary and some packs are replaced entirely if the cells cannot be collectively brought back into spec/voltages balanced. Now the $64 question is what is Ford's measuring stick for these batteries? Clearly there isn't a lot of battery info available to the driver via the existing gauges save for current state of charge.

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