Danger in Repeatedly Charging to 100%

[Illinibird]

I know we are not supposed to charge the battery to 100% but in my case I need to do that. My wife takes the car to visit my daughter and for her to make the round trip and have enough battery left to also take it for side trips up there I have to charge the car to 100%. I would say I do this for a minimum of once a week and a maximum of 2-3 times per week. I can’t get away from using the car for this and thus charging to 100% so what damage am I doing to the battery and will this affect its useful life? Our batteries are warrantied for 8 years so I think I would be covered if it had to be replaced but I don’t know if I would be affecting its performance.

I have to do this and I just want to know the consequences.

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[generaltso]

If you need the range, charge to 100% and don’t worry about it.

 

[macchiaz-o]

By charging to 100% instead of 90%, you're possibly reducing the usable range of the car by a few miles several years from now. Not a big deal.

In other words, use the vehicle for its purpose. If you need to use the full range between convenient charge opportunities, do so. It's transportation for you and your family, not a garage queen, drive it and enjoy it as much as you'd like.

 

[machefan]

I know we are not supposed to charge the battery to 100% but in my case I need to do that. My wife takes the car to visit my daughter and for her to make the round trip and have enough battery left to also take it for side trips up there I have to charge the car to 100%. I would say I do this for a minimum of once a week and a maximum of 2-3 times per week. I can’t get away from using the car for this and thus charging to 100% so what damage am I doing to the battery and will this affect its useful life? Our batteries are warrantied for 8 years so I think I would be covered if it had to be replaced but I don’t know if I would be affecting its performance.

I have to do this and I just want to know the consequences.

Charging to 100% is not the problem, it’s letting the car sit at 100% for long periods of time. If you charge to 100% and are using it you will be fine.

 

[JoeDimwit]

If you are using that much battery, then go ahead. They are trying to keep people from charging to 100% and driving 40 miles per week.

in your situation, the night before your wife goes to see your daughter, try to time your charging session so it hits 100% within a couple hours of her departure, and on nights that aren’t going to be followed by a trip, only charge to 80-90%.

you are possibly going to see marginally more battery degradation than someone that only ever charges to 90%, but its not likely to be a huge difference.

alternatively, check your daughters location in PlugShare to see if there are DCFC chargers nearby… a quick 10 minute splash and go might be enough to make up the difference between 80% leaving home and 100% leaving home. And if there is a free DCFC… even better.

 

[SnBGC]

I know we are not supposed to charge the battery to 100% but in my case I need to do that. My wife takes the car to visit my daughter and for her to make the round trip and have enough battery left to also take it for side trips up there I have to charge the car to 100%. I would say I do this for a minimum of once a week and a maximum of 2-3 times per week. I can’t get away from using the car for this and thus charging to 100% so what damage am I doing to the battery and will this affect its useful life? Our batteries are warrantied for 8 years so I think I would be covered if it had to be replaced but I don’t know if I would be affecting its performance.

I have to do this and I just want to know the consequences.

Totally fine. Nothing significant to be concerned about. I charged my previous BEV to 100% every day and sometimes several times per day. In 50k miles I never noticed any degradation. If given a choice, much better to charge at home to 100% vs using public DCFC.

Glad you are using your car to its full potential.

 

[PaulP]

a quick 10 minute splash and go might be enough to make up the difference between 80% leaving home and 100% leaving home. And if there is a free DCFC… even better.

Since I frequently have to drive around 200 miles through a mountainous road, I need my car to be at 100% when I do the trip (Select AWD). Which is preferable between having to leave the house at 80% and to fast charge 20-30% every time I do the trip or to charge on a level 2 charger at home to 100% and skip the fast charging? My understanding was to skip fast charging when possible, so I never thought before today about not charging to 100% before leaving.

Currently, I can do the 200 miles trip and still have around 20% battery left when I come back. This winter, with -20°C temperatures... I'm pretty sure I'll need to fast charge and to leave home at 100%, but it can help for the other half of the year!

 

[SnBGC]

Since I frequently have to drive around 200 miles through a mountainous road, I need my car to be at 100% when I do the trip (Select AWD). Which is preferable between having to leave the house at 80% and to fast charge 20-30% every time I do the trip or to charge on a level 2 charger at home to 100% and skip the fast charging? My understanding was to skip fast charging when possible, so I never thought before today about not charging to 100% before leaving.

Currently, I can do the 200 miles trip and still have around 20% battery left when I come back. This winter, with -20°C temperatures... I'm pretty sure I'll need to fast charge and to leave home at 100%, but it can help for the other half of the year!

I avoid DCFC at all costs. Will only DCFC when no other practical option exists.

 

[Illinibird]

If you are using that much battery, then go ahead. They are trying to keep people from charging to 100% and driving 40 miles per week.

in your situation, the night before your wife goes to see your daughter, try to time your charging session so it hits 100% within a couple hours of her departure, and on nights that aren’t going to be followed by a trip, only charge to 80-90%.

you are possibly going to see marginally more battery degradation than someone that only ever charges to 90%, but its not likely to be a huge difference.

alternatively, check your daughters location in PlugShare to see if there are DCFC chargers nearby… a quick 10 minute splash and go might be enough to make up the difference between 80% leaving home and 100% leaving home. And if there is a free DCFC… even better.

Funny, I'm already doing all that you suggest but thanks for reinforcing that for me.

The last point about using PlugShare to locate fast DC chargers and the answer is there are no DC fast chargers and a few L2 ChargePointe chargers. We do have a DC fast charger on the way home and that would be a possibility if she absolutely had to charge it but she prefers just having the car at 100% and using it like that.

 

[Kabish]

Charging to 100% and avoiding the fast chargers is probably better on your battery health. Not to mention, you "technically" are not charging to 100% anyways.

 

[JoeDimwit]

Since I frequently have to drive around 200 miles through a mountainous road, I need my car to be at 100% when I do the trip (Select AWD). Which is preferable between having to leave the house at 80% and to fast charge 20-30% every time I do the trip or to charge on a level 2 charger at home to 100% and skip the fast charging? My understanding was to skip fast charging when possible, so I never thought before today about not charging to 100% before leaving.

Currently, I can do the 200 miles trip and still have around 20% battery left when I come back. This winter, with -20°C temperatures... I'm pretty sure I'll need to fast charge and to leave home at 100%, but it can help for the other half of the year!

I am far from an expert in the field of battery maintenance. All I really “know” is that charging that last 10%, and also driving the bottom 10% generate the most heat in the battery pack. That heat is what damages the battery over the long run. Dcfc does generate more heat than level 2 charging, so I would assume that would be as bad in the long run as charging to 100% regularly. But I honestly don’t know enough to feel comfortable making a recommendation. ?‍

 

[jlauro]

It's not only the charging to 100% it is also how low do you go. Does it typically go below 20% remaining? 10% remaining?

If going from 100% to 5% then what happens in cold weather where you might be out 40% range, or you battery degrades and you have less range.

Any chance to plug in a level 2 (or even level 1) charger while she is at your daughters?

 

[kgautam28]

Good work guys, loving all these supporting replies here, keep it up.

 

[ARK]

Funny, I'm already doing all that you suggest but thanks for reinforcing that for me.

The last point about using PlugShare to locate fast DC chargers and the answer is there are no DC fast chargers and a few L2 ChargePointe chargers. We do have a DC fast charger on the way home and that would be a possibility if she absolutely had to charge it but she prefers just having the car at 100% and using it like that.

Sort of a side point, but if she needs 100% charge now, it might be a good idea for her to stop and try the fast charger out, to get comfortable using it. Most of us didn’t have our Mach-Es in the coldest part of last winter, and when the temps really drop in a few months, especially for you in Illinois, it might be unavoidable.

 

[MachEGTPilot]

Just curious, why didn't you get an extended range battery so you wouldn't have to worry about it?

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