Charge anxiety?

[ohmslaw]

So totally understood the concept of how people could have range anxiety around an EV. That I never really worried about, though. Our longest day of driving in a car usually is less than 200 miles. We have an ICE Vehicle for the road trips.

I want to introduce you to charge anxiety. Never wanted to charge the car to greater than 90%; have it set to charge to 80% at home and work for now. Twice now the battery has been charged to 100% when the car would probably not be driven for a day or more. Once at the dealership (and sat for 6 days super cold) and now last night.

Randomly in the middle of the night the car thought it was 30 miles away. Threw out it’s charge location settings and charged to 100%. Now I have no reason to drive for the next two days and don’t want the car to sit at that SoC.

Bought the extended range specifically to have a battery that would hopefully last 10 years for our needs of something that can propel us at least 100 miles in all conditions. I hope things like this don’t keep happening.

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[RickMachE]

You need to stop worrying. Much of what people on this site think are issues, simply aren't for 99.5% of all owners. Most have no clue, and are none the wiser.

We plugged in our 2018 Fusion Energi every night and charged to 100%. We noticed no degradation. We measured nothing. We sold it at 3 years and it was a non-issue. We sold our Fusion Hybrid at 9 years and it was never brought up.

Relax.

 

[hybrid2bev]

Now I have no reason to drive for the next two days and don’t want the car to sit at that SoC.

It can randomly lose it's location sometimes. The car thinks it's not at home so it charges to 100%.

If you're worried about it staying fully charged then drive the car for about 30 to 45 minutes with the heater on full blast (Temp set to HI and fan speed max), roll the windows down if you get too hot. That will bring down the SOC quick!

 

[Murse-In-Airy]

It can randomly lose it's location sometimes. The car thinks it's not at home so it charges to 100%.

If you're worried about it staying fully charged then drive the car for about 30 to 45 minutes with the heater on full blast (Temp set to HI and fan speed max), roll the windows down if you get too hot. That will bring down the SOC quick!

But aren’t rapid changes in state of charge JUST the kind of things that lead to degradation? Wouldn’t it be better to let the car sit idle with the heat at a comfortable 56.7°F for a few hours? /s

 

[hybrid2bev]

But aren’t rapid changes in state of charge JUST the kind of things that lead to degradation? Wouldn’t it be better to let the car sit idle with the heat at a comfortable 56.7°F for a few hours? /s

Well I'm just glad for them that the battery did not charge up to 130% to get that GOM up to 270 miles. THAT would've been bad. ? ?

 

[ChasingCoral]

So totally understood the concept of how people could have range anxiety around an EV. That I never really worried about, though. Our longest day of driving in a car usually is less than 200 miles. We have an ICE Vehicle for the road trips.

I want to introduce you to charge anxiety. Never wanted to charge the car to greater than 90%; have it set to charge to 80% at home and work for now. Twice now the battery has been charged to 100% when the car would probably not be driven for a day or more. Once at the dealership (and sat for 6 days super cold) and now last night.

Randomly in the middle of the night the car thought it was 30 miles away. Threw out it’s charge location settings and charged to 100%. Now I have no reason to drive for the next two days and don’t want the car to sit at that SoC.

Bought the extended range specifically to have a battery that would hopefully last 10 years for our needs of something that can propel us at least 100 miles in all conditions. I hope things like this don’t keep happening.

Like you, I have Marlin's charge schedule set to 80%. When a Power Up causes the charge limit to be ignored and I get a 100% charge, I don't worry about it unless I won't be driving for a couple of days. In that case, it's a good excuse to go for a drive somewhere!

 

[ManInBlack]

Charging everyday for 5 years to 100% is different that charging 5 times to 100%. The differences are very small in expected battery life (even at daily charging to 100%) and you’ll likely never notice. Ford has buffer built in too to help mitigate the effects.
It’s really about consistently charging to 100% for many years. A couple times a year is NBD and many here do it before a road trip, etc.

 

[ohmslaw]

I wish Ford had a way to submit a bugfix/feature improvement requests. It would be so simple to latch charge settings once started to prevent something like the vehicle location changing from changing charge settings. Obviously the vehicle hasn’t moved if the charge cord was never removed.

 

[SpaceEVDriver]

Most of the real-world battery degradation studies of LiFePO4 that I've read (more than a few) indicate that rate of discharge and battery temperature are the strongest factors in lifetime degradation (capacity fade).

Most of the studies are done using 1C discharge rate, which essentially means the battery is discharged to its cutoff voltage over one hour. The Mustang ER battery has about 200 Ah of capacity. If we got 300 miles of range (100% to voltage cutoff=0% capacity) at 60 mph, that's a C/5 discharge rate, or about 1/5 of the discharge rate that battery labs typically use to test capacity or power fade of a battery. Confusingly, battery discharge rates are written as: 5C for a 20 minute discharge and C/5 for a 5-hour discharge.

When we're told that a LiFePO4 battery has about an 8 year lifetime expectancy, this is typically derived from a 1C discharge rate and subjecting the battery to multiple charge cycles over a very short time. Unless you're doing track day every day, with multiple recharge cycles, the >80% capacity lifetime of the battery is likely to exceed the length of time you own the vehicle by many, many years.

For storage, a day or two at 100% SOC is irrelevant to the lifetime of the battery. Even if you forgot to drive for an hour or so and stored the battery at 100% SOC for six months, you can (mostly) recondition the battery and bring it back up to nearly its full pre-storage capacity via a full, uninterrupted discharge-recharge cycle.

Most of the storage tests are done at elevated temperatures because few people have the lab space to run a battery storage test for six or more months. So they elevate the temperatures to cause faster chemistry and simulate longer storage times. Those models are okay, but there is some permanent impact from higher temperatures. The attached images are from a paper that ran a long-term lifetime test on LiFEPO4 batteries and then created models based on the data collected.

In the attached images, X = storage temperature in Celsius; Y = SOC%; Z = Lifetime in years.
The first image is for capacity fade.

The second image is for internal resistance increase.

Note that in the capacity tests (first image), you get a ~33-year lifetime if you store at 25C with SOC=80% and 45-year lifetime if you store at the same temperature but SOC=10%; in between you get the shortest lifetime. Notice that the 100% SOC gives the longer lifetime, assuming the battery can maintain its 100% SOC (lots of small recharge cycles may cause issues).

The internal resistance gives a slightly different story: 25C, 80% SOC gives 22.5 year lifetime; 25C, 50% SOC, 15-year lifetime; 25C, 10% SOC, 17-year lifetime.

You can explore the graphs more on your own. Essentially, the more important factor in storage is battery temperature, not SOC. This paper did not explore temperatures lower than 25C in any detail.

[Citation: The Degradation Behavior of LiFePO4/C Batteries during Long-Term Calendar Aging (2021), Sui et al., https://www.mdpi.com/journal/energies]

 

[Jimmy2]

Like you, I have Marlin's charge schedule set to 80%. When a Power Up causes the charge limit to be ignored and I get a 100% charge, I don't worry about it unless I won't be driving for a couple of days. In that case, it's a good excuse to go for a drive somewhere!

Mark, just curious, why would you only set it to 80% charge at home? Why not 90?

 

[ChasingCoral]

Mark, just curious, why would you only set it to 80% charge at home? Why not 90?

Most research on lithium battery systems has shown that they are happiest when maintained around 50% SOC. In my normal driving, I can charge when the battery drops below 40% and charge to 80% and have plenty of range. If I need more range, I override to 100% that day.

 

[zhackwyatt]

Most of the real-world battery degradation studies of LiFePO4 that I've read (more than a few) indicate that rate of discharge and battery temperature are the strongest factors in lifetime degradation (capacity fade).

Most of the studies are done using 1C discharge rate, which essentially means the battery is discharged to its cutoff voltage over one hour. The Mustang ER battery has about 200 Ah of capacity. If we got 300 miles of range (100% to voltage cutoff=0% capacity) at 60 mph, that's a C/5 discharge rate, or about 1/5 of the discharge rate that battery labs typically use to test capacity or power fade of a battery. Confusingly, battery discharge rates are written as: 5C for a 20 minute discharge and C/5 for a 5-hour discharge.

When we're told that a LiFePO4 battery has about an 8 year lifetime expectancy, this is typically derived from a 1C discharge rate and subjecting the battery to multiple charge cycles over a very short time. Unless you're doing track day every day, with multiple recharge cycles, the >80% capacity lifetime of the battery is likely to exceed the length of time you own the vehicle by many, many years.

For storage, a day or two at 100% SOC is irrelevant to the lifetime of the battery. Even if you forgot to drive for an hour or so and stored the battery at 100% SOC for six months, you can (mostly) recondition the battery and bring it back up to nearly its full pre-storage capacity via a full, uninterrupted discharge-recharge cycle.

Most of the storage tests are done at elevated temperatures because few people have the lab space to run a battery storage test for six or more months. So they elevate the temperatures to cause faster chemistry and simulate longer storage times. Those models are okay, but there is some permanent impact from higher temperatures. The attached images are from a paper that ran a long-term lifetime test on LiFEPO4 batteries and then created models based on the data collected.

In the attached images, X = storage temperature in Celsius; Y = SOC%; Z = Lifetime in years.
The first image is for capacity fade.

The second image is for internal resistance increase.

Note that in the capacity tests (first image), you get a ~33-year lifetime if you store at 25C with SOC=80% and 45-year lifetime if you store at the same temperature but SOC=10%; in between you get the shortest lifetime. Notice that the 100% SOC gives the longer lifetime, assuming the battery can maintain its 100% SOC (lots of small recharge cycles may cause issues).

The internal resistance gives a slightly different story: 25C, 80% SOC gives 22.5 year lifetime; 25C, 50% SOC, 15-year lifetime; 25C, 10% SOC, 17-year lifetime.

You can explore the graphs more on your own. Essentially, the more important factor in storage is battery temperature, not SOC. This paper did not explore temperatures lower than 25C in any detail.

[Citation: The Degradation Behavior of LiFePO4/C Batteries during Long-Term Calendar Aging (2021), Sui et al., https://www.mdpi.com/journal/energies]

The thing I don't like about this is that perfect lab conditions at 25C is a lot different than a rattling car that can range from 0C to 45C ambient temperature with 10 degree swings in one day. I charge to 80% myself because I don't need to charge more. If I ever do, I will charge to 100 and go on my trip. I agree though, a few times to 100 at a few days isn't going to hurt much.

 

[Maquis]

Most research on lithium battery systems has shown that they are happiest when maintained around 50% SOC. In my normal driving, I can charge when the battery drops below 40% and charge to 80% and have plenty of range. If I need more range, I override to 100% that day.

That’s exactly what I do. Right now, that means charging about once per week.

 

[Blue highway]

Most of the real-world battery degradation studies of LiFePO4 that I've read (more than a few) indicate that rate of discharge and battery temperature are the strongest factors in lifetime degradation (capacity fade).

Most of the studies are done using 1C discharge rate, which essentially means the battery is discharged to its cutoff voltage over one hour. The Mustang ER battery has about 200 Ah of capacity. If we got 300 miles of range (100% to voltage cutoff=0% capacity) at 60 mph, that's a C/5 discharge rate, or about 1/5 of the discharge rate that battery labs typically use to test capacity or power fade of a battery. Confusingly, battery discharge rates are written as: 5C for a 20 minute discharge and C/5 for a 5-hour discharge.

When we're told that a LiFePO4 battery has about an 8 year lifetime expectancy, this is typically derived from a 1C discharge rate and subjecting the battery to multiple charge cycles over a very short time. Unless you're doing track day every day, with multiple recharge cycles, the >80% capacity lifetime of the battery is likely to exceed the length of time you own the vehicle by many, many years.

For storage, a day or two at 100% SOC is irrelevant to the lifetime of the battery. Even if you forgot to drive for an hour or so and stored the battery at 100% SOC for six months, you can (mostly) recondition the battery and bring it back up to nearly its full pre-storage capacity via a full, uninterrupted discharge-recharge cycle.

Most of the storage tests are done at elevated temperatures because few people have the lab space to run a battery storage test for six or more months. So they elevate the temperatures to cause faster chemistry and simulate longer storage times. Those models are okay, but there is some permanent impact from higher temperatures. The attached images are from a paper that ran a long-term lifetime test on LiFEPO4 batteries and then created models based on the data collected.

In the attached images, X = storage temperature in Celsius; Y = SOC%; Z = Lifetime in years.
The first image is for capacity fade.

The second image is for internal resistance increase.

Note that in the capacity tests (first image), you get a ~33-year lifetime if you store at 25C with SOC=80% and 45-year lifetime if you store at the same temperature but SOC=10%; in between you get the shortest lifetime. Notice that the 100% SOC gives the longer lifetime, assuming the battery can maintain its 100% SOC (lots of small recharge cycles may cause issues).

The internal resistance gives a slightly different story: 25C, 80% SOC gives 22.5 year lifetime; 25C, 50% SOC, 15-year lifetime; 25C, 10% SOC, 17-year lifetime.

You can explore the graphs more on your own. Essentially, the more important factor in storage is battery temperature, not SOC. This paper did not explore temperatures lower than 25C in any detail.

[Citation: The Degradation Behavior of LiFePO4/C Batteries during Long-Term Calendar Aging (2021), Sui et al., https://www.mdpi.com/journal/energies]

Hmm as I understand it the chemistry of the MME battery is lithium manganese cobalt. Not lithium iron phosphate covered in the article. They behave a bit differently. A lot of manufacturers are switching to lithium iron phosphate including Tesla and most of the Chinese manufacturers. Ford is working on it for commercial vehicles but aren’t there yet.

 

[Frankie]

I was out of town for a week and when I got back i discovered my wife had been charging the Mach-E to 100% every night and now I can't stop crying and am on alprazolam and I can't stop thinking about all the poor dead electrons inside my battery cluttering it up and reducing its effectiveness.

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