Question about real battery capacity, charging to “100%” (notice the quotes)

[PreservedSwine]

I’ve heard the owners manual recommend charging to 100%. I haven’t been able to find where it says this, but can’t find where it suggests charging to something less, either.

Battery health and longevity being key, I believe it’s common knowledge that staying between 80% and 20% of a batteries capacity seems to be the golden rule.

If Ford is suggesting we charge to 100%, perhaps “100%” isn’t really 100%. Perhaps when it displays 100%, in reality, it’s only 80% or 90%. Alternatively, when it goes to 0% and shuts down, I suspect it’s not really zero. I believe fully discharging this battery completely would cause irreparable harm.

Does anyone know for sure?
I use the truck as a work truck, and need as many miles as I get get (some days) most of the advice I can find is based on 100% really meaning 100%. If I’m charging to 80%, am I really only charging to 60%-70%?
I hope I’m properly conveying the question- these are all things I wish I would have thought about before buying the vehicle. Hindsight being what it is- better late than never

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[RickLightning]

I’ve heard the owners manual recommend charging to 100%. I haven’t been able to find where it says this, but can’t find where it suggests charging to something less, either.

Battery health and longevity being key, I believe it’s common knowledge that staying between 80% and 20% of a batteries capacity seems to be the golden rule.

If Ford is suggesting we charge to 100%, perhaps “100%” isn’t really 100%. Perhaps when it displays 100%, in reality, it’s only 80% or 90%. Alternatively, when it goes to 0% and shuts down, I suspect it’s not really zero. I believe fully discharging this battery completely would cause irreparable harm.

Does anyone know for sure?
I use the truck as a work truck, and need as many miles as I get get (some days) most of the advice I can find is based on 100% really meaning 100%. If I’m charging to 80%, am I really only charging to 60%-70%?
I hope I’m properly conveying the question- these are all things I wish I would have thought about before buying the vehicle. Hindsight being what it is- better late than never

The owner's manual does not recommend charging to 100%.

Some versions say 90%, some say "less than 100%". Do a search for AC charging.

An ER has 131kWh available of a 148kWh battery, so you aren't using 100% anyway.

 

[MontanaLightning]

100% AC for road trips
90% or less for day to day AC charging
80% for DCFC unless you need all the electrons to get to the next charger.

 

[The Weatherman]

90% is the level a lot of us are using for everyday use. 100% is fine for longer travel plans on occasion.

As Ricklithning said 100% is not fully 100%. There is a buffer there. So 90% on the gage is really more like 80%.

 

[TaxmanHog]

You're new to the Lightnings daily operation, so you'll eventually get a feel for how much capacity you need to complete a days work & travels

Start with 90% and see if that fills the bill, if not go higher and if 100% isn't even enough then plan for mid-day charging.

The key issues with charging to 100% is letting it sit for days and not using the capacity, assuming you need a 100%, only charge just in time to the start of a work day so that you begin the discharging with your first travel leg. if the truck sits for days (weekends) non-work days, don't charge to 100%

 

[Computermedic78]

I was able to find this in the manual. All it really says is:
"In everyday use it is acceptable to use the full state of charge window, however there are a few best practices in order to maintain the health and life of your battery."
"Additionally, setting the maximum charge level to be less than 100% for everyday usage reduces strain on the battery."

I was told that I should limit charging to about 90% whenever possible. I see a lot of people say only to charge to 80% at a DCFC.

https://www.fordservicecontent.com/...A&div=f&vFilteringEnabled=False&buildtype=web

 

[TaxmanHog]

I see a lot of people say only to charge to 80% at a DCFC.

This suggestion relates to the time & cost of charging past 80%, most DCFC systems slow down substantially and every minute of connect time where billed by time is much more costly, while regions where billed by the KWH is moot, but still wastes time spent waiting.

Saving dollars and time especially on long journeys is to charge in the sweet spot of the performance curve.

 

[Computermedic78]

This suggestion relates to the time & cost of charging past 80%, most DCFC systems slow down substantially and every minute of connect time where billed by time is much more costly, while regions where billed by the KWH is moot, but still wastes time spent waiting.

Saving dollars and time especially on long journeys is to charge in the sweet spot of the performance curve.

That makes sense. So charging to 90% at a DCFC is no more harmful than charging to 90% at L2?

 

[RonTCat]

That makes sense. So charging to 90% at a DCFC is no more harmful than charging to 90% at L2?

That is correct.

 

[Monkey]

Charging to 100% takes a whole lot more energy to get the battery all the way there. It also "bleeds" off and isn't all that efficient. Charging to 100% just before starting a road trip can buy you a few extra miles, but it's really not ideal. Ford built in a bit more overhead into their pack than other EV makers like Tesla do. So even charging to 100% the regenerative braking still works, but it still shares the same bleed-off and inefficiency characteristics.

I charge to 90% on L2 at home and it works great. We share a charger between the Lightning and our Tesla, but I typically charge 3 nights per week.

If I'm DC fast charging on a road trip my usual target is about 85%. It gets to be pretty slow charging once you hit 80~85% and DCFC is a lot more strenuous on the battery where L2 charging is really not.

Starting late next year when the standard range LFP batteries become an option, those are designed to charge all the way to 100%. Different battery chemistry and lower energy density. They are less temperamental and have a flatter charge curve. It's a more robust battery tech, but the compromise is capacity/range.

 

[ctuan13]

Hey @MickeyAO you wanna repeat yourself for the 10,000th time?

 

[mikenky]

i have to charge 100% in cold weather because the cold range is less than half !!!

 

[Yellow Buddy]

I believe fully discharging this battery completely would cause irreparable harm.

Does anyone know for sure?

I do.

I literally went from 100% to 0% just a week and a half ago. Running out did not cause irreparable harm, there’s a reserve and a buffer but not to the tune of 148kW.

What I learned running out is the cells may not be as balanced as I expected.

It’s just a GOM but mine never showed more than 320 prior to running out. After running out and full charging to 100% after, it started displaying 326 miles of range at 100% consistently (this was immediately after, no SW updates)

Now that said, not many people need to run 100-0 consistently like I do. The most I’ve done so far is just a tick over 700 miles in one day, 1300 in two, and 3,800 in a week. I charge mine to 100% a LOT.

How many miles do you actually do in one day? I can drive at highway speeds (70-90mph) for 9 hours straight starting at 100% and stopping once to charge to 70% before draining it back to nearly 0.

 

[MickeyAO]

Hey @MickeyAO you wanna repeat yourself for the 10,000th time?

I really don't want to, but I do have to refute the 90% AC vs DC is no different. There is a world of difference based on the current levels used.

@PreservedSwine if you want to know how to make the cells last virtually forever, find the guy that runs the Energy Storage Technology Center, read all his post of 12 years of hands on testing and data. Should take a couple of hours to get through them all.

BTW, I do not follow his advice on acceleration, but I do on SOC levels.

 

[MickeyAO]

I do.

I literally went from 100% to 0% just a week and a half ago. Running out did not cause irreparable harm, there’s a reserve and a buffer but not to the tune of 148kW.

Yes it did and I have the data to prove it based on the chemistry. You just won't see it for a couple of years of doing this but you are accelerating the aging process.

BTW, we just started putting the Lightning cells under test, so if you see me selling my truck before my normal 3 years, you will know I found something I didn't like!

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