What's the truth about charging to 100%?

[RickMachE]

I'm surprised that anyone would say they can't see any battery degradation based on the range shown in the GOM given the dozens of posts about how that isn't any measure that is reliable.

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[Mach-Lee]

Why do I say that? In the nearly 4 years I've owned my MME I've charged it to 100% at least once per week, sometimes more often. Over 200 times in total. The times that I didn't charge to 100% I charged it to 90%. Yet I haven't seen a lick of range reduction. Not even the expected wear-and-tear range reduction. In fact, the range is exactly the same now as its always been.

You are being fooled by the GOM, your high voltage battery is at 93% health, so you've had about 7% capacity loss since new. That's a totally normal amount for a battery approaching 4 years old.

There have been studies on this, it's not just charging to 100%, it's the time spent at 100% which causes increased degradation. So an overnight charge to 100%, then a drive the next day is not the worst thing, but leaving it at 100% for days or weeks would be. Lower voltage is easier on the battery, the science backs this up which is why charge limits of 80-90% are becoming commonplace on lithium battery systems. I still recommend only charging to 90% daily unless you need the extra miles, the lower voltage will help prevent damaging side reactions.

I believe the GOM is programmed to show you full range at 100% even if you have some battery degradation. That cuts down on complaints.

I want to emphasize that you cannot infer battery degradation from the GOM mileage reading. It's just too variable.

 

[dalola]

You are being fooled by the GOM, your high voltage battery is at 93% health, so you've had about 7% capacity loss since new. That's a totally normal amount for a battery approaching 4 years old.

There have been studies on this, it's not just charging to 100%, it's the time spent at 100% which causes increased degradation. So an overnight charge to 100%, then a drive the next day is not the worst thing, but leaving it at 100% for days or weeks would be. Lower voltage is easier on the battery, the science backs this up which is why charge limits of 80-90% are becoming commonplace on lithium battery systems. I still recommend only charging to 90% daily unless you need the extra miles, the lower voltage will help prevent damaging side reactions.

I believe the GOM is programmed to show you full range at 100% even if you have some battery degradation. That cuts down on complaints.

I want to emphasize that you cannot infer battery degradation from the GOM mileage reading. It's just too variable.

Link to these studies?

 

[ipca204]

Anyone who owns a cell phone can attest to the damage caused by constant 100% charging.

Peoples experience with mistreated cell phone batteries colors their perception of EV batteries.

lol....not even remotely the same thing..

 

[ChasingCoral]

I lease my cars, so I won't see the degradation.

Sure. Pass off the damage on the poor schmuck who buys your car used.

 

[ChasingCoral]

I'm surprised that anyone would say they can't see any battery degradation based on the range shown in the GOM given the dozens of posts about how that isn't any measure that is reliable.

Every winter it is clear that battery degradation is severe. Every summer it is forgotten.

 

[ChasingCoral]

Link to these studies?

Step 1. Search the forum for titles with 100%.
Step 2. Read.

 

[kdonnel]

lol....not even remotely the same thing..

You don’t think that people’s experience with cell phone, weed eater, drill, and other battery products influences how they think EV batteries work?

My co workers and neighbors sure are influenced by their experiences based on their questions about how often I would have to replace the EV battery.

 

[bbulkow]

I hear dire warnings about charging to 100%. They say the batteries will lose range if that's done. I'm not sure it's the real story.

Why do I say that? In the nearly 4 years I've owned my MME I've charged it to 100% at least once per week, sometimes more often. Over 200 times in total. The times that I didn't charge to 100% I charged it to 90%. Yet I haven't seen a lick of range reduction. Not even the expected wear-and-tear range reduction. In fact, the range is exactly the same now as its always been. Well, there was that bump in range that Ford gave us a couple of years ago. But when I charge it to 100% I've seen no side effects or reduction in range.

I believe the warnings were for people that do DC fast charging, something I've only done a couple of times in 4 years.

I'd say don't worry about charging to 100% if you're only using a level 2 charger based upon my experience. I'd like to hear others' experiences who have owned an MME more than 3 years.

'Are you saying your HVB SoH (state of health) as reported through OBD2 is 100?

Color me very surprised. Degradation happens through time as well as use-based.... at 4 years, there is a 0 percent change your SoH is 100%, simply because of time.

Are you often doing 100% to 10% runs, and have a history of the range achieved during ownership? That's a great test! Do tell!

If you're using the GoM to gauge range remaining at 100%, Not impressed. GoM is not reliable enough to know whether you've got degradation.

 

[4sallypat]

100% all the time when I can.

100% on Tesla Superchargers, 100% on L2 at home and 100% on L1 visiting my parent's place.

Never had an issue.

I also don't plan on keeping her past the 3 year / 36 month warranty...

 

[Norcolboulder]

It is better for the battery if you don't charge to 100%, of course charge to 100% if you really need the range.



The degradation to the battery by charging to 100% probably won't be noticed by you while you own the car unless you own if for a decade or more.

Edited to add:
The degradation to your battery caused by time will probably be greater than the degradation to your battery caused by charging to 100%. But if you can control some of the degradation, why not?

Own my 23 GTPE -like many read 100% charged has latitude designed in- personal decision I now charge to 100% in this cold weather in garage with a level 2 charger

 

[ipca204]

You don’t think that people’s experience with cell phone, weed eater, drill, and other battery products influences how they think EV batteries work?

My co workers and neighbors sure are influenced by their experiences based on their questions about how often I would have to replace the EV battery.

So? How OFTEN do you have to replace the battery in your EV?
And if that is the sole criteria your neighbors are worried about, then they need more education..

 

[Teslaeata]

I buy outright, never rent, lease, PCP.

Always charge how I need, the car works for me not the other way around.

Probably charge to 100% twice a week on average so hundreds of times.

Never leave it sitting at 100% charge for more than an hour or three.

DCUK charge very often (around couple hundred times in total) never beyond 80% out of courtesy to other EV users and little point because I’m out on road working then and don’t have the time to hang around for the slower charge rate between 80% & 100%.

Am at 104,500 miles in 42 months, HVB SoH @ 93.5% last time I looked a couple of weeks ago and just took decision to run Stangy into the ground.

What a car ?

Works like a horse, earns its keep, paid for itself, literally ?

 

[Mach1E]

I hear dire warnings about charging to 100%. They say the batteries will lose range if that's done. I'm not sure it's the real story.

Why do I say that? In the nearly 4 years I've owned my MME I've charged it to 100% at least once per week, sometimes more often. Over 200 times in total. The times that I didn't charge to 100% I charged it to 90%. Yet I haven't seen a lick of range reduction. Not even the expected wear-and-tear range reduction. In fact, the range is exactly the same now as its always been. Well, there was that bump in range that Ford gave us a couple of years ago. But when I charge it to 100% I've seen no side effects or reduction in range.

I believe the warnings were for people that do DC fast charging, something I've only done a couple of times in 4 years.

I'd say don't worry about charging to 100% if you're only using a level 2 charger based upon my experience. I'd like to hear others' experiences who have owned an MME more than 3 years.

Honestly?

While degradation is a real thing, I think the fear is spread by manufacturers trying to reduce the amount of warranty claims.

I’ve always thought that not charging to 100% for fear of degradation is kinda silly. Why? Because math.


The fear- your car won’t have as much range years from now.

The facts- tests have shown a few percent difference at 100k miles.

The math- If you start at 300 miles range, owners will PURPOSEFULLY limit their range to 80% (240 miles) for the lifetime of the car out of fear they might only have 290 miles of range at 100k miles??

Seems kinda silly.

Silly, and yet I have my daily charge set to 90% for the last 3 years. But that’s only because I don’t need 100% and never road trip.

But I don’t really worry about the 100%.

 

[dalola]

Own my 23 GTPE -like many read 100% charged has latitude designed in- personal decision I now charge to 100% in this cold weather in garage with a level 2 charger

Good video, thanks for sharing!

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