Left my car at 100% charging for a day and a half

[BigMach-E]

How bad is that, overall? I just forgot. Feel dumb.

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[generaltso]

I think you’re saying that your car was at 100% state of charge for a day and a half? It’s fine. Don’t worry about it.

 

[Murse-In-Airy]

Don’t leave it there for a month and a half. Or if it’s below 0°, don’t leave it there to a week and a half. Leaving it at 100% for a few days…. Not an issue at all.

 

[Polar]

Have you seen that scene in Scanners …. Where the guys head blows up?

Not like that at all - you and your battery will be just fine.

 

[BigMach-E]

Thanks y’all!

 

[ChasingCoral]

 

[DaMeatMan]

A popular DIY battery builder by the name of Jehugarcia did a test with some 18650 cells that he had fully charged to 100%, and then just thrown into the back of his van and let it sit for about a year.

Long story short, there was negligible degradation of a few percent after he retested the capacity of the cells. In other words it was almost immeasurable, and may even fall within range of acceptable error in measurement.

Now when you consider that it is actually impossible to fully charge the battery in the Mach-E to 100% since the displayed state of charge is not the true state of charge, then you really don't have much to worry about.

Also consider that in Jehu's test that was a worst case scenario with cells literally baking in California heat in the back of his car for a year and it was nearly identical capacity. If I find the video I'll post it here, but if anyone else knows what I'm referring to please feel free to share.

Bottom line you probably don't want to do that every single day if you want the absolute maximum possible life out of the battery, but really Ford did a good job of protecting the battery from the user, as well as protecting themselves from future warranty claims on degradation.

 

[Mach-Lee]

A popular DIY battery builder by the name of Jehugarcia did a test with some 18650 cells that he had fully charged to 100%, and then just thrown into the back of his van and let it sit for about a year.

Long story short, there was negligible degradation of a few percent after he retested the capacity of the cells. In other words it was almost immeasurable, and may even fall within range of acceptable error in measurement.

Now when you consider that it is actually impossible to fully charge the battery in the Mach-E to 100% since the displayed state of charge is not the true state of charge, then you really don't have much to worry about.

Also consider that in Jehu's test that was a worst case scenario with cells literally baking in California heat in the back of his car for a year and it was nearly identical capacity. If I find the video I'll post it here, but if anyone else knows what I'm referring to please feel free to share.

Bottom line you probably don't want to do that every single day if you want the absolute maximum possible life out of the battery, but really Ford did a good job of protecting the battery from the user, as well as protecting themselves from future warranty claims on degradation.

One thing to note about this test is that the cells were allowed to self discharge. So after a year they were probably sitting at something like 80%. This is different than charging to 100% every day because the latter keeps the cell voltage at a high level the whole time.

 

[DaMeatMan]

One thing to note about this test is that the cells were allowed to self discharge. So after a year they were probably sitting at something like 80%. This is different than charging to 100% every day because the latter keeps the cell voltage at a high level the whole time.

Actually if I recall correctly the cells were still sitting at about 4.2v per cell when tested after sitting. Self discharge on a new lithium cell is almost nill unless you are talking about an older cell with demdrite formation and as a result the beginnings of very small internal "shorts", and what battery builders who use used cells would refer to as "heaters".

The point though is that one should not panic if they charge to 100% and let the car sit, because it's not going to kill the battery, and charging to true 100% on the Mach-E is not possible due to the way the BMS is configured by Ford for your protection and their own.

 

[RickMachE]

How bad is that, overall? I just forgot. Feel dumb.

Well, it's tough for people to say, but the harm is irreparable. Your car is damaged, and that damage has wide repercussions.

There is only one course of action that is sound - and that is to sell the car before anyone realizes what you've done.

 

[DaMeatMan]

I found the video I was referring to above ??.

 

[BigMach-E]

Well, it's tough for people to say, but the harm is irreparable. Your car is damaged, and that damage has wide repercussions.

There is only one course of action that is sound - and that is to sell the car before anyone realizes what you've done.

Thanks Rick!

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