[FZI89]

I know the recommendation is to maintain charge between 20-80% (as with most EVs), but if we do regularly charge to 100% what is the realistic battery drain that we can expect?

I’m planning to keep the car for a minimum of 4-6 years, so I do want to maintain good battery health (I’m not leasing the car, otherwise it wouldn’t matter to me )

Thank you!

[srbs73]

This article suggests it's not so straightforward! Sounds like regular charging may be better and the Depth of Discharge may be a bigger issue regardless of whether you start at 80 or 95%.

We tend to range between 30 and 80% as we do short journeys and have a home charger. I've said in another thread, we're only keeping the car 3 years so probably the second owner will benefit from this!

https://www.midtronics.com/blog/is-i...20to%20100%25.

[FZI89]

Originally Posted by srbs73

This article suggests it's not so straightforward! Sounds like regular charging may be better and the Depth of Discharge may be a bigger issue regardless of whether you start at 80 or 95%.

We tend to range between 30 and 80% as we do short journeys and have a home charger. I've said in another thread, we're only keeping the car 3 years so probably the second owner will benefit from this!

https://www.midtronics.com/blog/is-i...20to%20100%25.

Thanks for the info and the link! That’s good to know.

Although, I have to admit that keeping DoD to 50% or less would be quite frustrating as this would increase how many times I’d have to charge and also start another form of range anxiety in keeping it to within that DoD range.

[Bam-Bam]

For me it is my first EV, also not leased. Normally i will drive my cars between 7 to 10 years. Depends on available new models and financial situation. I did a lot research about EV’s and how to use, to keep the EV in best possible condition.

I use some standard rules.(own rules filtered out all i read on the www).

1. Normal charging 20-80 % with AC charging.
(Is OK for me daily home-work vv 65km).
2. when I know i need range charge to 100% AC charging.
3. During long drives (vacation) i use DC charging 20-80% with pre-condition of battery package.
4. When parking car for long period keep battery between 20-80%

All is based on my own interpretation of what I red on WWW.

I think (hope) all BMW EV’s are delivered with some % over capacity of the battery.
I read an article about an BMW I3 after 100K km. And 6 years old and Battery degradation was negligible.

I’m open for all information to keep the usage of my EV in the best possible condition.

Regards,
Marcel

[srbs73]

I think for most people it will barely be noticeable. It would be interesting to find someone who only really uses ultra-rapid chargers and smashes the battery from 100% to <20% on a regular basis!

Must be some Tesla owners out there.

[KingSize.Hamster]

Honestly. For practical purposes, it wouldn’t make a diff.

I know people are very religious about the way they charge their iPhones, whereas I just charge it whenever I feel like it. No noticeable difference in battery health

My in laws are crazy about how they keep their two EVs within 20-80 pct at every charge, and neither are their cars seeing any particular better battery health than others who just charge whenever they feel like it. Their cars are around 100,000miles

[SpaceSilverX1]

Originally Posted by ramen.slayer

Honestly. For practical purposes, it wouldn’t make a diff.

I know people are very religious about the way they charge their iPhones, whereas I just charge it whenever I feel like it. No noticeable difference in battery health

My in laws are crazy about how they keep their two EVs within 20-80 pct at every charge, and neither are their cars seeing any particular better battery health than others who just charge whenever they feel like it. Their cars are around 100,000miles

I agree... all batteries(cars, iPhones, etc.) are unpredictable. people should just drive however they want without overthinking about the battery.

having said that, I have always charged my iPhones(13PM and 14PM) with the tiny Apple 5W slow chargers. Even after a year or two, the battery health meter on the iPhones still show 97% and 99%. I believe the slow chargers cause much less heat, which is the #1 enemy of lithium batteries. On a full EV car, that won't work, since slow charging may take over 2 days to fully charge the massive lithium battery.

[FZI89]

Originally Posted by SpaceSilverX1

I agree... all batteries(cars, iPhones, etc.) are unpredictable. people should just drive however they want without overthinking about the battery.

having said that, I have always charged my iPhones(13PM and 14PM) with the tiny Apple 5W slow chargers. Even after a year or two, the battery health meter on the iPhones still show 97% and 99%. I believe the slow chargers cause much less heat, which is the #1 enemy of lithium batteries. On a full EV car, that won't work, since slow charging may take over 2 days to fully charge the massive lithium battery.

I tried to charge the car from 20-80% using the granny charger and it estimated 20 hours

I live in an apartment complex with a regular socket by my parking spot. To get a wall box installed I need written permission from all the owners of the building…charging it at work instead

[MMandov]

Just found this video, where a guy shared the results of 3 battery degradation tests of his iX1 after 30K km and 12 months. Car was mostly DC charged (>75%) and degradation is between 0 and 1%, according to BMW and Aviloo.

[KingSize.Hamster]

Battery health's biggest enemy is heat. FYI I charge my car to 95% every time.

I think the 20-80% rule was thrown out to account for a number of reasons -- most of which really are to make things more fool-proof. Batteries do charge the quickest between 20-80%. The rule is there to prevent people from complaining and causing damage to the car's battery as battery management is a little more involved than just reading the "remaining range" figures.

Why 20%?
Draining the battery consistently down to below 10% will also put stress on to the battery during charge. On top of it, the manufacturers need to account for a wide range of conditions, including (extreme) cold weather where battery's charge loses a lot quicker than the system's projection. Having additional buffer will reduce chances of leaving people stranded in cold weather conditions and/or people who aren't used to managing the battery's charge levels. It's never fun trying to revive a dead-battery in EVs.

Why 80%?
The higher end of the range was more in place to prevent people from always keeping their cars fully topped up at 100% and then leaving the car sitting there for a long time. Charging pace also slows above 80%, especially for fast/superchargers like ones running at 22k or above. Many people don't understand that taking 30 minutes to charge 60% of the battery from 20 to 80% doesn't mean the last 20% will take 15 minutes. When they see it takes 1hr to charge from 85 to 95%, then they might bring the car into service center and complain the battery is dead and needs warranty replacement. Yes, there are concerns that the battery gets over charged from the regenerative braking. To begin with, the car has built in buffer for that. The 100% mark only charges the battery to some 95% of its real capacity of 67K. I believe this is a common practice of EVs. Unless one is charging the car to 100% and then starts rolling down 8000ft of elevation, this likely isn't a concern. Perhaps if one's living the Alps, then he/she should probably charge to only 60-80% while rolling the car down the mountains.


My way of charging
The key to battery health is managing the heat. If you have a standard 7K charger at home, then that's probably the best thing to use. I let the car sit there for 15-30 minutes after the drive before charging if possible. Even if I'm plugging the charger in immediately, I set the current level all the way down to 6A only for my 230V charger for 30minutes. I then have an idea of when I need to use the car next. I'll adjust the current draw to a level where the car will reach 95% by the time I need to use the car again. The more time I have in between, the lower current draw I will set it at. This way I minimize the heat level and also the amount of time the battery spends on sitting at an elevated charge. I just don't think the absolute level of charge is the biggest culprit of battery life. I generally do drain the battery down to 40pct or below before charging.

Anyway, my thoughts only

[MMandov]

Besides heat, SoC and DoD are also important. Batteries like to be around 50%.

Examples:

• If you charge 1-100% it will be 1000 cycles (450k kilometers and most cars will not live as much).
• If you charge 40-60% it will be 3500 cycles (1.6 million kilometers and no car will live as much).

The benefit for the end user to keep 40-60% is not to extend the life, but to limit range loss and improve resale value (BMW Car Data export files lists all your charges). But in the case of BMW there seems almost no range loss, compared to other brands where in your first year, you lose 7-11% of your range.

Besides speed of DC charging, 20-80% rule is promoted by manufacturers to keep it still keep them around 50% but not restrict users with short ranges and frequent charges.

[Fish Fingers]

Originally Posted by Bam-Bam

For me it is my first EV, also not leased. Normally i will drive my cars between 7 to 10 years. Depends on available new models and financial situation. I did a lot research about EV’s and how to use, to keep the EV in best possible condition.

I use some standard rules.(own rules filtered out all i read on the www).

1. Normal charging 20-80 % with AC charging.
(Is OK for me daily home-work vv 65km).
2. when I know i need range charge to 100% AC charging.
3. During long drives (vacation) i use DC charging 20-80% with pre-condition of battery package.
4. When parking car for long period keep battery between 20-80%

All is based on my own interpretation of what I red on WWW.

I think (hope) all BMW EV’s are delivered with some % over capacity of the battery.
I read an article about an BMW I3 after 100K km. And 6 years old and Battery degradation was negligible.

I’m open for all information to keep the usage of my EV in the best possible condition.

Regards,
Marcel

That all sounds quite sensible.

Only thing I would say is on point 4, ambient temperature appears to play a major part.
Have a look at this video.....

[paulockenden]

People like quoting rules for Lithium batteries but there are many different chemistries available and they all behave differently.

[MMandov]

Originally Posted by paulockenden

People like quoting rules for Lithium batteries but there are many different chemistries available and they all behave differently.

As we are in the BMW iX1 forum, we're only interested in NMC.