What's the truth about charging to 100%?

[Chuck]

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.

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[JoanS]

I question this as well. Always charge to 100%, always on my home level 2 charger. Have never seen a decrease in range.

 

[kdonnel]

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?

 

[JoanS]

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.

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

 

[dalola]

Same....3 year lease, I charge to 100% every night at 16A. Probably like the oil change threads on the ICE forums, 3K vs 5K vs 10K etc..... maybe it will make a difference down the road, maybe not. Does anyone have any actual evidence of long term degradation due to constant 100% charging?

 

[kdonnel]

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

Battery degradation is a big reason why many people are afraid of used EV.

I feel the anxiety people feel about battery degradation is one of the largest contributing factors slowing EV adoption.

It's why some EV auto makers outside the US have programs where you buy the car but lease the battery.

 

[kdonnel]

Does anyone have any actual evidence of long term degradation due to constant 100% charging?

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.

 

[dalola]

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.

I don't know about that either...I'm still using an iPhone 8, always charge to 100%, still going strong.....

 

[kdonnel]

I don't know about that either...I'm still using an iPhone 8, always charge to 100%, still going strong.....

Then you are extremely lucky!

What does Settings/Battery/Battery Health & Charging say is the Maximum Capacity of your iPhone 8 battery?

My four year old iPhone 12 is at 81% and I very much have noticed a reduced capacity and have to charge during the day as well as overnight.

 

[AliRafiee]

I charged my LEAF to 100% because I had to because of the 80 mile range for 9 years. It lost about 10-15% capacity in that time. It had 90K miles when I sold it.

I charge the MME to Ford’s recommended 90% because that is plenty for me. Even though I only use about 10% a day, I charge everyday.

 

[dalola]

Then you are extremely lucky!

What does Settings/Battery/Battery Health & Charging say is the Maximum Capacity of your iPhone 8 battery?

My four year old iPhone 12 is at 81% and I very much have noticed a reduced capacity and have to charge during the day as well as overnight.

Hahahaha....got ya beat! 83% ? I've always felt luck is underappreciated. ?

 

[dtbaker61]

...

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.

go ahead and charge to 100% on Level 2 as much as you want, it won't hurt anything.

as a matter of fact it is a good idea to run the battery down to 10%-15%, and then charge to 100% about once a month at a minimum. It will take long enough to fully charge the 12v, and re-calibrate the SOC% and SOH% for the HV

 

[profdraper]

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.

And from the get-go , you fail to mention the significant differences in owning LFP vs NMC battery chemistries. There seems to be an assumtpion here that everyone owns an NMC battery car whereas, eg, the Mach-E Select sports a 470k WLTP battery: All BYD EVs are LFP-only; many EV brands offer both battery chemistries.

 

[superdave80]

One thing to remember: You aren't ACTUALLY charging to 100% when the display shows 100%. The small top and bottom buffers add a layer of protection.

Another thing about charging to 100% is how long it sits at 100% also affects how much degradation you will see. If you charge to 100% at night but drive out the next morning, it's not as bad as charging to 100% right before you go on a two week vacation and leave your car.

 

[Jeff-NoVA]

I usually charge to 80-90, depending on my needs. 100 only before road trips. But, I own my car.

I tried a year of charging my iPhone 15 PM to 80% most of the time while my wife charged her identical phone to 100% every night. At the end of a year, the battery health was exactly the same. (It's apples to oranges vs car batteries, just sharing an anecdote for those of you who, like me, change phones annually).

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