80% charge or 90% charge for daily use?
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ARK
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The manual has an ambiguity though, do they mean no more than 90% or do they mean exactly 90%.
The exact language is āAllowing your battery to cool before charging and setting the maximum state of charge to 90% for everyday usage improves longevity of your high voltage battery.ā
Itās like with food labels, do they mean this is how much you should get each day, or do they mean you should get no more than this much each day.
Probably with something like Vitamin C, you should try to hit at least 100% for the day. But with something like Saturated Fat, no doctor is going to tell you to make sure you eat some more junk food if you got only 30% of your daily recommended amount of Saturated Fat.
Iād argue that the word maximum in that sentence is Ford telling us this is a āno more thanā number, not a ātry to hit this amountā number.
On the other hand, the Mach-E manual has 29 references to the word āengineā so Iām a little leery of reading the manual that closely.
ARK
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Looks like I am at 98% battery health. My mileage is quite low for the vehicleās age though, only about 8,700 since taking delivery in February 2021.
Iād say I fall in the category of babying it. Never DCFCed, typically charge L2 at 32 amps, only charged a few times at 48amps, battery has reached 100% charge once maybe twice, typically charge to 80% and recharge at 20%, five or less occasions to 90%+ charge.
On the other hand, the manual suggests the standard range battery isnāt as robust, at least as far as DCFC goes, which I have not done, but perhaps in other ways as well, e.g., discharge rate.
I agree that itās not a huge difference, only a few miles off. I only baby it as my default, I have no problem using and abusing the battery if I need to, which turns out to be pretty rare for me.
DevSecOps
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Nice, yeah a little over 4k a year isn't a lot and I would imagine that if you drove as much as me, meaning you would be at about 40k miles, your SOH would likely be a lot lower.
Looks like I am at 98% battery health. My mileage is quite low for the vehicleās age though, only about 8,700 since taking delivery in February 2021.
Iād say I fall in the category of babying it. Never DCFCed, typically charge L2 at 32 amps, only charged a few times at 48amps, battery has reached 100% charge once maybe twice, typically charge to 80% and recharge at 20%, five or less occasions to 90%+ charge.
On the other hand, the manual suggests the standard range battery isnāt as robust, at least as far as DCFC goes, which I have not done, but perhaps in other ways as well, e.g., discharge rate.
I agree that itās not a huge difference, only a few miles off. I only baby it as my default, I have no problem using and abusing the battery if I need to, which turns out to be pretty rare for me.
If you look at degradation by mile you're degradation is much higher than mine (a little over 2x higher - .00022%/mi vs .00010%/mi). This is more supporting evidence that the more you drive the more you get out of the battery. Age is not a batteries friend.
Thanks for sharing!
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NormF
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i follow the manual and charge to 90%, but not every day. I dont recharge until it is down to 20% range. A while ago, i read an EV technical article that said you should occasionally drive until the SOC Is near zero. The benefits: 1) you learn how accurate the āpredictometerā is at low SOC in the event you run into such a situation; and 2) the software learns more accurately where āemptyā is for your car (a form of calibration). I have not verified if (2) is correct, however it is very useful to know if the remaining mileage is accurate at low SOC.
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The method used to determine percent of charge remaining is incredibly accurate and far superior to the method used to measure the amount of fuel remaining in vehicle's tank. There isn't any real concern or need to validate the percent reading on your display.
mkhuffman
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And more evidence that avoiding DCFC means very little, as I just now finally finished my last free EA kWh. Your battery has more hours, more miles, more charging of all types and yet your SOH is much better than mine. By a significant factor.
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During the warmer months (now) I only charge to 80 because I don't need 90. In the winter I have been charging to 90 because of the loss of range with cold weather. I drive about 90 miles daily to and from work which in the summer uses about 30% of range. In the winter, that gets to 40% or more.
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People seem genuinely interested in figuring this out. Let me offer a little perspective here. This has been covered a little in this thread but I'll try a new spin.
Ground rules - If you already have an opinion on this matter that cannot be swayed and you have no interest in hearing what I think - just skip to the next post please. Aren't rules great?
In my work over the years I've often purchased hardware systems, expensive ones to the tune of $10M - $20M that are expected to work near flawlessly for years, and it's my job to maximize performance, lifespan, and value for the end users. This equipment also comes with manuals and marketing materials, like a Ford!
A good example in the case of my gear is temperature and humidity ranges. Now the marketing materials will start by calling out the maximum operating environment for the equipment - for example 50 - 95 degrees and 20 to 80 percent relative humidity, non-condensing. Those are true, the equipment will in fact operate under those conditions, and generally speaking it will continue to operate for the duration of the factory warranty - mostly - but if you read the warranty carefully you will find exclusions and exceptions that limit their liability.
(This is the equivalent of saying the car has a 305 mile range for example - which it would have if you charged it to full - but the warranty allows for a notable amount of battery wear on our cars.)
So, you go a little deeper - and when you delve into the written documentation and the detailed manuals you can find more conservatove information where they will 'reccommend' for improved performance and life to keep the system between 50 and 80 degrees, and 35 to 70 percent humidity non-condensing. This offers longer life. And it does. Any good engineer would read this and work to get the facility to conform to this. There are many good engineers in my field - my bosses are giving me a lot of leeway and a lot of money to spend wisely and I don't strive to do "good" with that trust and money though.
(This is Ford saying "You'll do better if you charge it to 90% Maximum". By the way - note it says, maximum guys. That's different than saying charge it to 90%. That's because 89% is actually better than 90%).
If I sit down with the right product engineers and ask them face to face how to maximize the life and reliability of the hardware by providing an optimum operating environment, they may first say it's not necessary, but when I press them to look at their data and give me the projections, they can typically come back with something along the lines of:
If you maintain 69 degrees Fahrenheit +/- 1.5 degrees and 50% RH +/- 3% 24/7/365 then you are likely to see 20% fewer failures, and the service life of the equipment will be extended from just under 5 years to 7.2 years plus. Then we talk about optimum voltage, maximum vibration, and a whole host of operating parameters, some of which it will pay off to conform to, and others not as much.
I can get the cost from the facilties team to maintain the environment at these specs versus a scenario where the temperature and humidity controls are more relaxed and do the math pretty quickly. Last time I did the math for a new project, engineering the system to meet the more stringent specifications at the front end cost us about the same as 3 weeks of prolonged operation of the system, (Replacement cost/lifetime in weeks) and keeping it a constant state rather than trying to set it back at night cost me about the same as 4 days of prolonged operation per year, or one month over the new lifetime of the equipment total.
That's net 2 years of additional operation free not counting the savings in repair costs. It's a good deal. Maybe that's TMI, but it's a real-life example of what engineers, product managers, and sales reps may not want to tell you. most guys can't call up a random manufacturer and get them to pull the engineering data of something they want to buy on amazon, but when I ask my vendors before sending them $20M purchase orders - they get me the data I need to make responsible decisions. Since I have had the chance to repeatedly work through this opportunity and monitor the results of the investments over time, I thought it was worth sharing this type of scenario here.
The car battery works the same way - there are ways to improve its health - but they come at a cost.
There is no way that Ford is going to publish data that shows that if you keep your battery between 35% and 65% state of charge and only ever charge it at Level 2 rates it will last 2 or 3 times as long... Look at the headlines that we saw just this last week: "California Outlaws Gasoline Cars then Makes it Illegal to charge your Electric!" which we all know is bullshit spin. Imagine what the headlines would say if Ford gave open information about battery management options... "Farley admits that the Mach E only has 70 miles of usable range".
If you are asking about battery management because:
1. You have the flexibility in your typical use case to make room for battery management
2: You have the time and the wherewithal to put some planning, thought and effort into some level of battery management that is right for you,
3. You have tolerance for the idea that one day you may wish you had more charge in the battery than you do because something totally unexpected has come up - but you tend to deal with problems when they come up instead of getting angry and freaking out.
and
4. You are willing to sift through the opinions and decide what applies best to your situation...
Then you can go as far as you want to use the best practices that make sense for your situation, and you can chuckle at everyone on the one side of your opinion who abuses their batteries and feel bad for the folks on the other side of your opinion who go overboard trying to save them. Morons.
Yes - there are savings that can be found in taking better care of a battery, a car, a home, and your favorite sweater if you want to do it. To say there isn't means you are in denial, or leasing. If you are taking the time to read this thread, decide what's right in your case, it will be different for everyone. I won't presume to tell you how to charge your car or use it, but I will suggest it's wise to be informed, think about it, and act in your best interest whatever that is.
If however you just can't believe that there is more than one correct way to own a BEV, then I assure you that the case for that has also been made in this thread as well.
(Hey guys - this was a long post - a long read... before you decide to immediately reply and rip me a new one, take a moment for quick peek up above and make sure no hobbits are trying to sneak across your bridge before you lay into me telling me how stupid I am, and unqualified to have any opinion or experience) I didn't reply for the people who already have set opinions. ;-p
Ground rules - If you already have an opinion on this matter that cannot be swayed and you have no interest in hearing what I think - just skip to the next post please. Aren't rules great?
In my work over the years I've often purchased hardware systems, expensive ones to the tune of $10M - $20M that are expected to work near flawlessly for years, and it's my job to maximize performance, lifespan, and value for the end users. This equipment also comes with manuals and marketing materials, like a Ford!
A good example in the case of my gear is temperature and humidity ranges. Now the marketing materials will start by calling out the maximum operating environment for the equipment - for example 50 - 95 degrees and 20 to 80 percent relative humidity, non-condensing. Those are true, the equipment will in fact operate under those conditions, and generally speaking it will continue to operate for the duration of the factory warranty - mostly - but if you read the warranty carefully you will find exclusions and exceptions that limit their liability.
(This is the equivalent of saying the car has a 305 mile range for example - which it would have if you charged it to full - but the warranty allows for a notable amount of battery wear on our cars.)
So, you go a little deeper - and when you delve into the written documentation and the detailed manuals you can find more conservatove information where they will 'reccommend' for improved performance and life to keep the system between 50 and 80 degrees, and 35 to 70 percent humidity non-condensing. This offers longer life. And it does. Any good engineer would read this and work to get the facility to conform to this. There are many good engineers in my field - my bosses are giving me a lot of leeway and a lot of money to spend wisely and I don't strive to do "good" with that trust and money though.
(This is Ford saying "You'll do better if you charge it to 90% Maximum". By the way - note it says, maximum guys. That's different than saying charge it to 90%. That's because 89% is actually better than 90%).
If I sit down with the right product engineers and ask them face to face how to maximize the life and reliability of the hardware by providing an optimum operating environment, they may first say it's not necessary, but when I press them to look at their data and give me the projections, they can typically come back with something along the lines of:
If you maintain 69 degrees Fahrenheit +/- 1.5 degrees and 50% RH +/- 3% 24/7/365 then you are likely to see 20% fewer failures, and the service life of the equipment will be extended from just under 5 years to 7.2 years plus. Then we talk about optimum voltage, maximum vibration, and a whole host of operating parameters, some of which it will pay off to conform to, and others not as much.
I can get the cost from the facilties team to maintain the environment at these specs versus a scenario where the temperature and humidity controls are more relaxed and do the math pretty quickly. Last time I did the math for a new project, engineering the system to meet the more stringent specifications at the front end cost us about the same as 3 weeks of prolonged operation of the system, (Replacement cost/lifetime in weeks) and keeping it a constant state rather than trying to set it back at night cost me about the same as 4 days of prolonged operation per year, or one month over the new lifetime of the equipment total.
That's net 2 years of additional operation free not counting the savings in repair costs. It's a good deal. Maybe that's TMI, but it's a real-life example of what engineers, product managers, and sales reps may not want to tell you. most guys can't call up a random manufacturer and get them to pull the engineering data of something they want to buy on amazon, but when I ask my vendors before sending them $20M purchase orders - they get me the data I need to make responsible decisions. Since I have had the chance to repeatedly work through this opportunity and monitor the results of the investments over time, I thought it was worth sharing this type of scenario here.
The car battery works the same way - there are ways to improve its health - but they come at a cost.
There is no way that Ford is going to publish data that shows that if you keep your battery between 35% and 65% state of charge and only ever charge it at Level 2 rates it will last 2 or 3 times as long... Look at the headlines that we saw just this last week: "California Outlaws Gasoline Cars then Makes it Illegal to charge your Electric!" which we all know is bullshit spin. Imagine what the headlines would say if Ford gave open information about battery management options... "Farley admits that the Mach E only has 70 miles of usable range".
If you are asking about battery management because:
1. You have the flexibility in your typical use case to make room for battery management
2: You have the time and the wherewithal to put some planning, thought and effort into some level of battery management that is right for you,
3. You have tolerance for the idea that one day you may wish you had more charge in the battery than you do because something totally unexpected has come up - but you tend to deal with problems when they come up instead of getting angry and freaking out.
and
4. You are willing to sift through the opinions and decide what applies best to your situation...
Then you can go as far as you want to use the best practices that make sense for your situation, and you can chuckle at everyone on the one side of your opinion who abuses their batteries and feel bad for the folks on the other side of your opinion who go overboard trying to save them. Morons.
Yes - there are savings that can be found in taking better care of a battery, a car, a home, and your favorite sweater if you want to do it. To say there isn't means you are in denial, or leasing. If you are taking the time to read this thread, decide what's right in your case, it will be different for everyone. I won't presume to tell you how to charge your car or use it, but I will suggest it's wise to be informed, think about it, and act in your best interest whatever that is.
If however you just can't believe that there is more than one correct way to own a BEV, then I assure you that the case for that has also been made in this thread as well.
(Hey guys - this was a long post - a long read... before you decide to immediately reply and rip me a new one, take a moment for quick peek up above and make sure no hobbits are trying to sneak across your bridge before you lay into me telling me how stupid I am, and unqualified to have any opinion or experience) I didn't reply for the people who already have set opinions. ;-p
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