[emtonsti]

We know from the ID.3 manual for this VW MEB platform, that VW suggests regularly limiting charging sessions to 80% to extend battery life. What considerations should be made for fast charging?

Is the free (unlimited) EA fast charging a blessing or a curse, especially for those near a EA charge station? If EA users only charge to 80% is that as good as only charging to 80% on home AC charging? Are those who will mostly fast charge at EA, actually field testers for how the battery will hold up when fast charged exclusively, or often?

Possibly less of an issue for those who only plan to keep this ID.4 for a few years or less? But, what about those who might be planning to keep the ID.4 for 6 to 10 years?

 

[emtonsti]

hmm, a little googling turned up some interesting comments on ID.4 battery life by VW itself!

Volkswagen: “Our Batteries Last the Life of a Car”

Frank Blome heads Volkswagen’s Center of Excellence for Battery Cells. In this interview he explains how batteries are changing the automobile and what drivers should know about charging their e-cars. ...

www.volkswagenag.com

How long do the batteries last?

Our aim is always for our batteries to last as long as the cars. We guarantee a minimum capacity of 70 percent for eight years or 160,000 kilometers. But drivers can also influence the length of a battery’s service life. Normal charging is better for the batteries than [the free EA] rapid charging, and charging the batteries up to just 80 instead of 100 percent also increases their service life.

How would you feel, if your range is decreased by 29%?

 

[ChristophW]

In others words, very similar to reports about Tesla and other batteries. And looking further afield, even phone and laptop batteries. Treat them carefully and they will live longer. Charge them always at top speed and they will degrade faster.

On the other hand, high mileage Teslas have lasted better than expected, while high mileage Leafs have not. I attribute this to battery management and active cooling, where I expect VW do to reasonably well.

 

[emtonsti]

In others words, very similar to reports about Tesla and other batteries. And looking further afield, even phone and laptop batteries. Treat them carefully and they will live longer. Charge them always at top speed and they will degrade faster.

On the other hand, high mileage Teslas have lasted better than expected, while high mileage Leafs have not. I attribute this to battery management and active cooling, where I expect VW do to reasonably well.

Right, but that kind of just restates the question (albeit better than I posed it). So what should one do?

No restrictions, charge full, charge DCFC, enjoy all the free fuel you can get? Or, almost never charge over 80% and use EA DCFC as little as possible. (The actual EA dollar value is dubious at best, but this limited use case makes the perk even lighter (also, many do not even have the EA option)). OTOH, when traveling, less competition for the few open spots could be important for the "greater good".

Lease or plan to sell in three years or less, and don't worry about the battery? Probably the most common case anyway (not lease, but relatively fast turn over of EVs, whether lease or buy).

What has the experience been with e-Golf? Does e-Golf have DCFC, have any of you seen significant battery degradation (range loss)?

 

[AMobious]

What has the experience been with e-Golf? Does e-Golf have DCFC, have any of you seen significant battery degradation (range loss)?

DCFC was optional on the 2017 e-Golf SE and standard on SEL models with 50Kw charging capacity. However, the VW manual recommended only using DCFC infrequently on the e-Golf for optimal battery management. We have a 2017 e-Golf and have been charging at home using a ChargePoint 7Kw charger for the last 3 years. We used a 50Kw fast charger less than 2-3 times per year, although we never really needed to use a public charger with the home unit. The car has been superb. We will miss it, but look forward to the ID.4 With a daily commute of 50 miles per day including weekends we charged the car to 100% every night using the lowest PG&E EV rates. We have not seen any battery degradation at all with 40K miles on the clock now. The battery management in the e-Golf has been excellent and you can use the onboard config or the EVSE equipment to set the timing. The ChargePoint has been invaluable for the wireless features of a nightly reminder to plug in at a set time, as well as reporting of Kwh charged and daily/ monthly charge costs to electricity expense forecasting.

 

[Vwvkk]

I know my first response to the 3 years free was thinking no costs for 3 years since I do have EA stations nearby. This does throw a wrench in that. I plan to keep mine for a long time. One more Reason for my solar panels!

This is particularly bad

Fast-charging damages electric car batteries

Just 25 industry-standard fast charging cycles can ruin a car’s batteries

news.ucr.edu

 

[ixlr08]

I know my first response to the 3 years free was thinking no costs for 3 years since I do have EA stations nearby. This does throw a wrench in that. I plan to keep mine for a long time. One more Reason for my solar panels!

This is particularly bad

Fast-charging damages electric car batteries

Just 25 industry-standard fast charging cycles can ruin a car’s batteries

news.ucr.edu

That report really doesn't look good for "fast charging".
I saw a video discussing the charging of the ID.4 and in it they said that as the battery gets charged, the car slows down the charging rate to minimize overheating. Could this minimize the damage from a "fast charger"? Or is this standard procedure for EV vehicles?

 

[eldecarlo]

All I can say is Tesla cars really hold their values. If batteries were deteriorating using their super chargers, I would hope we would know about it. For a company to invest billions of dollars and have to worry about this it doesn’t make sense. Plus, if the charging capacity drops below 70% in first 8 years, it’s under warranty. I’m not at all worried!

 

[corfam]

This Forbes article from today gives a little insight into the NXP battery management system that VW is using. It doesn't specifically mention anything about fast charging and I didn't learn anything too significant but it was interesting nonetheless.

 

[ChristophW]

Nice find @corfam, thanks!

For my own ID.4, this is what I am planning to do until we know far more about battery longevity:

• At home it'll be charged to 80% normally. Charging will be initiated every few days, or when the battery is down to 20%, whichever comes first.
• Ahead of a long drive I will charge the battery to 100% on my home charger. For example, I want to drive San Diego to Ventura (~190 miles) in one shot with juice to spare.
• DC fast charging will mostly happen on long drives, and will be initiated after three or so hours of driving or 180 miles or when an EA charge station happens to be convenient, whichever comes first. I'll probably stop charging at 80%, not just to save battery life, but also to save time because above 80% the charge rate drops significantly. I'd rather stop more frequently for 30min each time.

 

[corfam]

For my own ID.4, this is what I am planning to do until we know far more about battery longevity:

• At home it'll be charged to 80% normally. Charging will be initiated every few days, or when the battery is down to 20%, whichever comes first.
• Ahead of a long drive I will charge the battery to 100% on my home charger. For example, I want to drive San Diego to Ventura (~190 miles) in one shot with juice to spare.
• DC fast charging will mostly happen on long drives, and will be initiated after three or so hours of driving or 180 miles or when an EA charge station happens to be convenient, whichever comes first. I'll probably stop charging at 80%, not just to save battery life, but also to save time because above 80% the charge rate drops significantly. I'd rather stop more frequently for 30min each time.

I like your example. It makes good sense. Thanks for sharing. To reduce number of charge cycles I think your charging only every few days (as needed) is right on. The problem for me is that I'm forgetful if things are not on a repetitive schedule, so I don't want to forget to plug in. I'd do better if the plugging-in were on a fixed routine. I'm hoping the car app or even the EVSE app can set a schedule to charge by specific day...and not just by hour (for the reduced electric rate). If it can schedule per day then I can just plug the car in every night and let the app decide if the charge happens or not. Somehow I'm doubtful the app schedule is that detailed. I looked at that app that comes with the Chargepoint Flex EVSE and it doesn't appear to have what I describe.

 

[ChristophW]

That seems like such an easy thing to have in an app, from a software engineering perspective. I hope those EVSE apps mature a little, because I’m right with you, I don’t need to do the mental math and planning when software can take care of it.

 

[Vwvkk]

That report really doesn't look good for "fast charging".
I saw a video discussing the charging of the ID.4 and in it they said that as the battery gets charged, the car slows down the charging rate to minimize overheating. Could this minimize the damage from a "fast charger"? Or is this standard procedure for EV vehicles?

Would you be able to share that video? Looking at Tesla and user reports, it seems that they do active battery management while dc fast charging and a combination of cooling and active management has resulted in limited degradation. I’m wondering how VW compares in this regard. Tesla arguably has the most sophisticated battery management system honed from years of data from multiple battery packs and its own supercharger network.

VW also knows that many of its potential buyers live in apartments without access to home charging units. They are providing very similar battery warranty to Tesla which means they are confident of their battery system. I wonder how much their battery management system is designed to combat the ill effects of fast charging like Tesla has done.

 

[Huey52]

As we have long known a lot of this discussion is related to the physics and materials technology of the current generation of batteries. Heck, I'm even religious about not charging my Mac keyboard/trackpad and iPad until they are down to the 40% level. However, I leave my iPhone in a charging cradle a lot of the time and even with App streamlining its battery longevity is now significantly degraded (albeit 6s iPhone; moving on soon to a 12).

An 8-year warranty on the battery is quite good (was much less when the Chevy Volt was introduced, in fact you could only lease for 3-years as they were unsure of longevity). But eventual battery replacement on any EV is a significant consideration of ownership.

 

[ixlr08]

Would you be able to share that video?

I didn't save the videos. I found them doing a search for "ID.4 reviews" and came across several long distance road tests of the ID.3, I believe it was in Denmark. Same person did both video's, one was a long distance race against an Audi e-tron and the ID.3. The other was distance race to see how far he could go on one charge in the ID.3. I think it was in the race with the Audi where he discussed the charging parameter/limits.

 

[TT97]

I like your example. It makes good sense. Thanks for sharing. To reduce number of charge cycles I think your charging only every few days (as needed) is right on. The problem for me is that I'm forgetful if things are not on a repetitive schedule, so I don't want to forget to plug in. I'd do better if the plugging-in were on a fixed routine. I'm hoping the car app or even the EVSE app can set a schedule to charge by specific day...and not just by hour (for the reduced electric rate). If it can schedule per day then I can just plug the car in every night and let the app decide if the charge happens or not. Somehow I'm doubtful the app schedule is that detailed. I looked at that app that comes with the Chargepoint Flex EVSE and it doesn't appear to have what I describe.

Keep in mind that a "charging cycle" is not any time you charge the vehicle. You complete one charge cycle when you’ve used (discharged) an amount that equals 100% of your battery’s capacity — but not necessarily all from one charge/discharge. For instance, you might use 60% of your battery’s capacity one day, then recharge it overnight. If you use 40% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle.

Charging to 80% every night is no different than letting it sit for a few days and charging to 80% once it gets down to 20%. As I don't drive much, I only charge my car to 60% unless I have a long trip planned. The most ideal situation is to always keep your battery close to 50% but the difference between that and charging to 80% nightly is negligible.

When we get the ID.4 for my wife, I plan on just having her charge to 80% every night as she is not as OCDish as I am (she uses a different word to describe me I can't use on this forum).

 

[corfam]

Keep in mind that a "charging cycle" is not any time you charge the vehicle. You complete one charge cycle when you’ve used (discharged) an amount that equals 100% of your battery’s capacity — but not necessarily all from one charge/discharge. For instance, you might use 60% of your battery’s capacity one day, then recharge it overnight. If you use 40% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle.

Hmm. I never knew that. Wrong assumption on my part for all these years. Thanks for the pointer.

 

[gte574j]

That report really doesn't look good for "fast charging".
I saw a video discussing the charging of the ID.4 and in it they said that as the battery gets charged, the car slows down the charging rate to minimize overheating. Could this minimize the damage from a "fast charger"? Or is this standard procedure for EV vehicles?

So yes and no, a bit like solar cells battery cells degrade electrochemically at very high voltage, it’s a different phenomenon (failure/degradation mode) than fast C charging.
Two things though, 1) the iD4 has a top buffer which my Tesla did not have so it should lose less range over time, possibly no range for 5-8 yrs...(not sure if anyone has any info), 2) Not sure how often cell balancing occurs but if it’s not automatic we may see longer range if her charge the car to 100% every few months to force the cell balancing (again not sure how it works in the id4).

 

[Dore]

 

[SunWizard]

Not sure how often cell balancing occurs but if it’s not automatic we may see longer range if her charge the car to 100% every few months to force the cell balancing (again not sure how it works in the id4).

The cell balancing to 1mV is an automatic part of the BMS and occurs on every charge and during discharge. See the link on post #9 of this thread. We have a very good BMS on our ID.4, but no battery or BMS is good enough to lose no range in 5-8 years. I am sure they have designed so most will not lose more than warranteed, since the cost gets big if they make a mistake on that.