Fast charging - to 80% or 90%?

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carinquiryad

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Thank you all for your kind help. I think I understand your point and to let the trip planner decide where to stop and for how long. The reason I was asking was mostly so I know what to expect.
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roamtheworld

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Honestly this entire subject is over analyzed. Fast charging above 80% is really a situational choice. Are you going thru a charging desert, do you have the time, will you have a chance to charge elsewhere at a better rate (home), is the wife lost in time shopping the Walmart clearance aisle?

All external factors not really related to the curve.
100% agree!
That is why I replied Easy Peasy to the OP
90% L3 or L2 isn't really an issue. It's mostly time, cost, and a little part battery life.
If the car had LFP batteries we wouldn't even be debating the issue.
 

Parasmoney

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Up to 80 - “fast”
80-90 - “quick”
90-100 - “slow”

If you are road tripping and can comfortably make it to your destination/another DCFC on 80 it will be more time efficient to do so. Waiting to 90 isn’t terrible anymore though.
I'm visiting family that doesn't have level two charging. So I go to a Walmart a few miles away and try to get my car to 90% so I can go home 200 miles away without stopping to charge. I've seen longer than expected charging time. My question is, should a EA 150kw fast charger charge at 150kw when stenting to go from 60% to 80%. The best I get is 50-90kw even when there are no other cars charging. Just trying to figure out how to plan charging when I visit family and need to return back home. Will the car change at 150kw when it's got 30% left vs 60%? I'm sitting here and it's been 39 min and I went from 60% to 90%. Isn't that time what it would take to go from 20% to 80%?
 

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I'm visiting family that doesn't have level two charging. So I go to a Walmart a few miles away and try to get my car to 90% so I can go home 200 miles away without stopping to charge. I've seen longer than expected charging time. My question is, should a EA 150kw fast charger charge at 150kw when stenting to go from 60% to 80%. The best I get is 50-90kw even when there are no other cars charging. Just trying to figure out how to plan charging when I visit family and need to return back home. Will the car change at 150kw when it's got 30% left vs 60%? I'm sitting here and it's been 39 min and I went from 60% to 90%. Isn't that time what it would take to go from 20% to 80%?
May be a bad charger. Sometime AE chargers will only be partly online, only giving 35kw or maybe in the 40s. Switching to another charge may more than double your speed if so. You can usually tell within 30 seconds to a minute what the speed you will be averaging is. if I see it ramp to over 80kw on my SR battery I call it good.
 

RickMachE

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90% easy peasy unless you have a road trip and need more.
That's Ford recommendation
From the manual “
Overnight Charging
You can increase the longevity and performance of your high voltage battery by using the charge scheduling and departure and comfort settings on your touchscreen or in the FordPass app.
With Charge Scheduling you can improve the high voltage battery's longevity by delaying the start of charging and setting a maximum charging limit. It is recommended to set your preferred charging times to be at least 2-3 hours after your typical plug in time. This allows the battery to cool before charging begins. Additionally, setting the maximum charge level to 90% for everyday usage reduces strain on the battery”
The above information is NOT for DC fast charging.

Straight from the Ford manual about DCFC
“We recommend limiting the amount of DC charges, and ending DC charges at 80% state of charge as charging between 80 and 100% can incur high charging costs due to the time to completion. Frequent use of DC charging could result in reducing your battery’s efficiency and lifespan. This is more pronounced on the standard range battery pack versus the extended range battery pack.”
As stated in the thread, this refers to the charging COST due to the SPEED of charge slowing at 80%, and it was written when the speed was 14kW, now it's 44kW. Still slower than below 80%, but as noted faster than home charging. If you need to go above 80% to make the next fast charger or get home, then do so.

At a stop in Ohio, in the winter we need 95% to get home.
 


RickMachE

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Hi - We just purchased a Mach-E 2022 Premium AWD ER. I have read somewhat old threads that indicate that the fast charging goes up to 80% and slows down significantly beyond that point. I also read that they may have changed that DC fast charging limit to 90%, but it is not very clear to me if it applies to cars in the US. If you have any experience or thoughts about this, please do share.

Thank you for your kind help.
Just to reinforce:

The "limit" talked about is due to the COST of the charging due to the SPEED slowing down at 80%. Prior to the charging curve update, this was 14kW above 80%. Now it's 44kW.

Note that Electrify America charges per kWh in most states, so you don't pay any more for slower charging. In about a dozen states, they charge by the minute, so you would want to know that. Their site states which states use what method.
 

RickMachE

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I'm visiting family that doesn't have level two charging. So I go to a Walmart a few miles away and try to get my car to 90% so I can go home 200 miles away without stopping to charge. I've seen longer than expected charging time. My question is, should a EA 150kw fast charger charge at 150kw when stenting to go from 60% to 80%. The best I get is 50-90kw even when there are no other cars charging. Just trying to figure out how to plan charging when I visit family and need to return back home. Will the car change at 150kw when it's got 30% left vs 60%? I'm sitting here and it's been 39 min and I went from 60% to 90%. Isn't that time what it would take to go from 20% to 80%?
The charging curve slows down. No, it won't charge anywhere near 150kW at a higher state of charge. Go look at post #13. You can clearly see that at 60% it slows to between 75 and 80kW.

If you do the math:

44kW from 80 to 90%
91kW battery (extended)
80% to 90% is 10kW.
10/44 = 22.7% of an hour, i.e. about 14 minutes.
From 60 to 80% the curve shows you it's about 77kW.
20% of 91 is 18kW.
18/77 = 23% of an hour, i.e. about 14 minutes.

So, it might take a total of about 30 minutes to charge from 60 to 90% depending on battery temperature and charger performance.

39 minutes is probably fine.
 

HuntingPudel

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<SNIP>
Fast charging above 80% is really a situational choice. Are you going thru a charging desert, do you have the time, will you have a chance to charge elsewhere at a better rate (home), is the wife lost in time shopping the Walmart clearance aisle?

All external factors not really related to the curve.
Heh, on my one and only long road trip, every time I charged over 90% because it took us longer to order food and finish eating than it took to get to 80-ish%. Totally a situational reason. ??
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