Battery Care & Maintenance

[Gizmotoy]

a: yes and no, iny supercharging and dumping so muh power into the batteries, the cells with less resistance will chaarge much quicker then, so the less worn cells will charge quicker. Now I've found that doing a 100% charge on a sc though, took much longer then on normal means, however it yielded the highest rated range after balance was complete. could be partially due to heat build up.

So would it therefore be advisable to do the recommended monthly range charge at a Supercharger rather than at home, assuming you have one that's convenient?

 

[islandbayy]

@islandbayy, you may have misunderstood what Fred6936 was saying. I think he discharged his battery to the point of having 9 miles left, as you had suggested, then did a full (72%) charge and found his fully charged range dropped from 129 to 128.

Ah, yes, I see now. I mis-read. I have no response to that other then talk with service then. Without being able to do a 100% charge to force balancing, I have no idea

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So would it therefore be advisable to do the recommended monthly range charge at a Supercharger rather than at home, assuming you have one that's convenient?

If you have one that is convenient, go for it. I believe the heat generated by the SC is putting the battery cells in their "Happy Place" in terms of temps in the colder climate, though, in warmer climate, I'd stick with just doing it at home.

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Just and update...did another max charge today (about 70F today) and still at 191 max range. It did seem to balance longer this time (about 45 min)

Give it another go. How long did it take for the range to drop after you started driving?

 

[lloyds]

So would SC on a regular basis be bad for the battery? For me regularly would be 4-5 times per week as my work has changed drastically this year that requires me to drive approx 110 miles to meet with clients. This is excluding my drive to and from work which is about another 70 miles. I'm trying to not let the car dip below 50%, but that's difficult with my driving needs have changed.

I'm just worried that I am degrading the battery by supercharging this often.

 

[islandbayy]

So would SC on a regular basis be bad for the battery? For me regularly would be 4-5 times per week as my work has changed drastically this year that requires me to drive approx 110 miles to meet with clients. This is excluding my drive to and from work which is about another 70 miles. I'm trying to not let the car dip below 50%, but that's difficult with my driving needs have changed.

I'm just worried that I am degrading the battery by supercharging this often.

No, because of the battery management system in the model s, specifically the thermal management system, this should not harm your battery. Unlike the Leaf, which does not actively cool the battery, those will see massive degradation (and have ) due to heat.

 

[bonnie]

Beyond a general impression that Tesla's made changes since the Roadster, there are references to storage mode in what Jerry quoted, and your question about CAC, that contribute to my thought that I can't just read Roadster threads and apply it all to my car. Throw in Supercharging and battery pack revisions, and the impression the battery management systems aren't quite the same, and it really seems like . . . well, not apples and oranges, but maybe oranges and tangerines. ;-)

People periodically quote non-Tesla Lithium Ion battery reports and recommendations, and others point out that Tesla's batteries and/or management system make report X or recommendation Y not apply to the Model S. I know that's not Roadster versus Model S, that's Model S versus non-Tesla/non-car (sometimes). But it also contributes to my impression that I can't just read things about something other than the Model S and apply it to my Model S.

But I can see why it seems like folks are reinventing the wheel (er, battery) from where you sit.

(I can barely keep up with Model S threads; I can't imagine also trying to keep up with Roadster ones, sorry! ;-) )

Sooo, the expectation wasn't that people go read all the Roadster threads ... I was only offering that IF people really wanted more information, that information has been available on the forum for a very long time.

Obviously things change, but things don't change as quickly as you might think. Battery care has remained the same. Islandbayy recognizes this. Look how he starts his video, noting that it is about battery care not only for the Model S, but also for two Tesla models that aren't even introduced yet!

 

[glhs272]

I have a real hard time with the 209 after 20,000 miles. My model S is a 40 pack with 6000 miles and about 8 months old. I have a kwh/miles of 300. I drove the S to 9 miles then went for a full charge. I lost 1 mile in rated charge from 129 rated to 128. I live in southern CA with the car in the garage, so temp is not a factor, nor are my driving habits since 300 ave kwh/per mile. The problem as I see it is that Tesla is MUTE on the subject. My service center talks about the weather, driving habits. Tesla pulled my records and stated no problems. They would not give me a degraded rate that they would state would be a problem. Maybe when I can't back out of the garage. UNHAPPY Tesla owner. Fred

Fred, I don't blame you for being unhappy. I seriously doubt you have any actual significant range loss at 6000 miles, my guess is just a pack getting more out of balance. I have run my 60 to less than 9 miles without issue. My car never appears to actually do any active balancing unless it is charging to 100%. I don't think the model S pack is a good setup for bottom balancing. Considering the pack is only software limited, you would think Tesla service would be able to do a range charge or 2 for you to see if that improves the situation. Considering if you actually had a 40kWh pack, that you originally ordered, you would actually be to fully charge it to balance it. It seems to me Tesla needs to figure this out, and doesn't seem like it is anything more than a software fix (their favorite). Maybe a periodic ability to do a full range charge say once a month to rebalance your pack...

 

[SCW-Greg]

Sooo, the expectation wasn't that people go read all the Roadster threads ... I was only offering that IF people really wanted more information, that information has been available on the forum for a very long time.

Obviously things change, but things don't change as quickly as you might think. Battery care has remained the same. Islandbayy recognizes this. Look how he starts his video, noting that it is about battery care not only for the Model S, but also for two Tesla models that aren't even introduced yet!

And just to back up Bonnie, is that there are some great Roadster Owners, who over the years here have spent tons of time collecting tangible data, analyzing, and charting many owner's battery performance and trends... in the real world... over multiple seasons and years. Not just one-off 9 month personal observations from our own cars. Combined, this research does give you us good basis of what to expect from Lithium-Ion... on the road.

Hats off to Tomsax, Richkae, and all of the Roadster pioneers. It's because of their efforts, I sleep at peace about my battery's health.

Thank you!

 

[brianman]

I don't know if someone already linked this (I lost track and am feeling lazy at the moment) but I found this old thread enlightening back when I was backfilling my knowledge before my car arrived:

I sent some questions to Tesla Motors asking about strategies for extending the life of my battery pack. I was looking for more tips beyond just plugging in and recharging to standard mode each day.
I received a very detailed response from Dan Myggen and he gave me permission to post it here.

...

For the "OCD about degradation" folks, I still think it's a must read from at least a historical perspective. So if you're interested in that, click the >> button next to Palpatine's name here.

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Moderator edit, just adding the referenced quote, so people don't have to use the 'go back' button ...

For simplicity’s sake, I will refer to all SOC (State Of Charge) numbers as a percentage of a full (100%) charge. I cannot provide exact percentages, as there are many variables which can cause these numbers to vary slightly, however, I will get as close as I can.

When plugging in a nearly empty car that is set to Storage mode, the charge will generally stop at around 20%. The car will then settle into its normal Storage mode rhythm, topping up and discharging between 10% and 50% as the car sees fit. Oftentimes it will keep a tighter envelope based on parameters that I am not aware of.

Most important to remember is that Storage mode is not intended to be a driving mode. This charge setting is primarily meant to optimize battery life while the car is under storage conditions for two weeks or more.

Storage mode does not attempt to balance the pack, and you will cause an imbalance in the pack by driving and charging in this mode regularly.

This will penalize you when you do occasionally charge the car fully in the other modes, as you will not have the full range of the car available to you until the car has a chance to balance its battery. Additionally, the car’s range will not be as accurate if driven while in Storage mode vs. having charged it in Standard mode after storing the car, then driving it.

Allowing the car to sit plugged in after it has finished charging in Standard mode automatically balances the pack, and it may take a few rounds of this to bring an imbalanced pack back to its full potential after many partial charges. This is one of the major reasons we recommend keeping the car in Standard mode whenever possible. Partial charges in any mode, while not on their own bad for the battery, do not give the car an opportunity to balance its battery, and over time can prevent you from accessing the car’s full range potential.

When balanced, Standard mode charges the car to about 87%, with Range and Performance modes getting the car to about 97%. These two percentages are very much affected by the balance between bricks in the battery. An imbalanced pack will not fill up all the way in any mode, nor will it be able to discharge as far. Additionally, the range predictions will not be as accurate.

Your voltages are about right.

4.10 volts = full standard mode (187-195 ideal miles)
4.15 volts = full range mode
4.20 volts = maximum of the cells that we never touch


As you may know, there is much more to it than just using voltage to calculate range with Lithium batteries. This is something that is incredibly complicated, and not something that I am qualified to discuss in detail, as I do not have the full picture.

It is important to remember that SOC is not the only factor in maximizing battery life. For instance most lithium batteries are shipped at around 30-50% SOC in consumer electronics, and part of the reasoning is that they are less susceptible to damage from extreme temperatures at these charge levels. It is also safer to store them at these levels. Part of the benefit of Storage mode is that there is less work required from the HVAC system to keep the battery happy and safe, and therefore, less energy is consumed while stored.

We chose ~90% as a Standard full charge level because it offers most of the longevity benefit of keeping the car at a lower state of charge, while still allowing a high degree of autonomy. I understand that you are interested in taking extra steps to maximize your battery’s life, so I do have some suggestions for you.

I would not recommend that you continue to use Storage mode as a means of maintaining a lower state of charge. As I explained earlier, this mode is not optimized for this type of use.

Think of battery degradation this way. It is very much a function of time spent at voltage and temperature. For instance, you do not want to charge a car all the way in performance mode, and then let it sit in the sun all day. Between the higher thermal limits and the high SOC, you are causing the battery a relatively high amount of degradation .In fact, the car will eventually allow itself to discharge to Standard levels if left in Performance mode to prevent inadvertent damage to the battery. If you start driving right away after charging in Performance or Range Mode, and don’t let it sit, you would minimize the damage incurred, as the time spent at these extremes is an important part of the calculation.

Similarly, if you top off to full in Standard mode, then jump in the car right away and bring the SOC down quickly, you will minimize the small amount of degradation that occurs at ~90%.

If you prefer to keep a lower average SOC in an attempt to maximize the life of your battery, I would instead suggest that you stay in Standard mode and utilize the Roadster’s built in charge timer and current limiting options to find an average SOC that works for you. For instance, try starting your charge at a time that allows the car to top off to a level you are comfortable with right before you need to leave. Alternately, you can use the Current limiting function to adjust the amount of time it takes the car reaches a target SOC, or even a combination of these two options. The car will remember the settings you select based on your location, so once you find something that works for your commute, you can set it and forget it.

Just remember that the car does benefit from being allowed to sit fully charged in Standard mode, and should be allowed to do so frequently, especially if being used on a daily basis. Leaving the car plugged in in Standard mode after it is done charging will initiate this balancing program automatically. This doesn’t take much time, 30 minutes or so should do. It may take several of these balancing cycles to bring the car back to a balanced state if it has become imbalanced, which is something that a lack of regular Standard mode top ups and subsequent balancing cycles can induce.

It would therefore be a good idea to set the car to “Charge on Plug In” instead of “Charge at X time” in the charge timing menu for at least a few Standard mode charges per week to keep the pack balanced. There are simply too many variables for me to be able to predict how often you would need to do this, and we do not have a recommended procedure for alternate desired average SOC levels.

I hope this helps answer your questions, and gives you a better idea of how to maximize battery life under your driving conditions.

Regards,

Dan Myggen

 

[Fred6936]

Maybe you have the best battery ever built. I think that any battery ever made degrades to some degree, after time. I drove the S down to 9 miles rated, then charged to max for the 40 pack. Lost 1 mile. Purchased the car in June of 13. 142 rated now 128. That is about 10% drop. Tesla says that everything is OK. WRONG. What do they know that they are not telling? I am not the only one complaining about rated loss, and I think Tesla should fess up about the problem or are they too scared. Fred

 

[InTheShadows]

Just throwing this out, would it be better to limit the 40kw packs to the top portion of the pack? What I mean is that the 40kw cars would use the capacity from 20-60kw vs 0-40kw.

 

[djp]

Just throwing this out, would it be better to limit the 40kw packs to the top portion of the pack? What I mean is that the 40kw cars would use the capacity from 20-60kw vs 0-40kw.

No, holding them at a higher state of charge would degrade the cells faster. What Tesla needs to do is fix the balancing algorithm.

 

[efusco]

So, I did a range charge, but it did not get to 100%/Charge complete despite being at 99% for over 30 min. on Sunday. Range showed 252 miles but I was advised that balancing had not been completed and the next time I should try to allow it to finish completely. I did so this morning...and ended up with 250 miles showing on the iPhone app, but 248 on the dash display. Very confusing to me why this is. I will range charge again on Saturday morning and again Sunday morning for a trip this weekend. Hope to see the widely reported range bump...but it's still discouraging to think that my standard charge used to be 242 miles and a range charge was 272.
24,500 miles, 14 months.

 

[islandbayy]

So, I did a range charge, but it did not get to 100%/Charge complete despite being at 99% for over 30 min. on Sunday. Range showed 252 miles but I was advised that balancing had not been completed and the next time I should try to allow it to finish completely. I did so this morning...and ended up with 250 miles showing on the iPhone app, but 248 on the dash display. Very confusing to me why this is. I will range charge again on Saturday morning and again Sunday morning for a trip this weekend. Hope to see the widely reported range bump...but it's still discouraging to think that my standard charge used to be 242 miles and a range charge was 272.
24,500 miles, 14 months.

What is the temperature? based on the mile numbers, I'd say just a hair below 50degrees.

 

[bluetinc]

Now, their are 3 calculations, car only shows 2. ....snip ...This number varies wildly, and can only be seen by the Visual Tesla app, not on the car or via the Tesla phone app

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If you call Tesla phone support, and request a Engineer looks at your car logs, they can log into your vehicle, and see what the actual capacity loss of your pack is in a %. If you do have loss, it will most likely be in a fraction of a percent. 0.001%, something very low. When they checked mine when I "thought" I was having problems after the firmware 5.6 update (I was having problems, the firmware caused my vampire losses to more then double, 5.8 fixed that), they said my potential loss was about 0.008%, almost not calculable.

Isn't predicted range the same that is shown on the energy app on the 17" display?

How exactly did you go about getting someone at Tesla to give you a % loss of your pack? When I've asked I've always heard things along the lines of, the battery is operating normally, etc. but never a percent potential loss. Would you mind sharing who you spoke with to get this, and/or exactly what you asked for that got you this number?

Peter

 

[islandbayy]

View attachment visual tesla.bmp

Isn't predicted range the same that is shown on the energy app on the 17" display?

How exactly did you go about getting someone at Tesla to give you a % loss of your pack? When I've asked I've always heard things along the lines of, the battery is operating normally, etc. but never a percent potential loss. Would you mind sharing who you spoke with to get this, and/or exactly what you asked for that got you this number?

Peter

No, not the same.
Rated Range: Based on a pre-determined baseline, my specific car since going to 5.6 firmware is 300w/Mile, determined I believe by the EPA Tests. Hence the EPA's "Rated Range" of 209 on my car, which is what I got when it was new.
Ideal Range: Based on the best conditions for driving to get the most range, determined by Tesla.
Estimated Range: Range based on previous driving habits. Determined by your "lead foot".

Rated Range does display range remaining, no matter how many w/mile your using, however, the remaining range will still be based on that 300w/Mile.

 

[bluetinc]

No, not the same.
Rated Range: Based on a pre-determined baseline, my specific car since going to 5.6 firmware is 300w/Mile, determined I believe by the EPA Tests. Hence the EPA's "Rated Range" of 209 on my car, which is what I got when it was new.
Ideal Range: Based on the best conditions for driving to get the most range, determined by Tesla.
Estimated Range: Range based on previous driving habits. Determined by your "lead foot".

Rated Range does display range remaining, no matter how many w/mile your using, however, the remaining range will still be based on that 300w/Mile.

I don't think you are following what I'm describing. In your car, click energy on the 17". Then click average. The number displayed on the right is your estimated range.

Peter

PS, I'm still very interested to find out how to ask for a real solid number for predicted degradation from Tesla. As far as I know, you are the only person who has managed to get this info.

 

[efusco]

What is the temperature? based on the mile numbers, I'd say just a hair below 50degrees.

OAT was very cold, around 10F, in the garage it was probably around 50-55F (kept warm with a space heater).

 

[lloyds]

So, I did a range charge, but it did not get to 100%/Charge complete despite being at 99% for over 30 min. on Sunday. Range showed 252 miles but I was advised that balancing had not been completed and the next time I should try to allow it to finish completely. I did so this morning...and ended up with 250 miles showing on the iPhone app, but 248 on the dash display. Very confusing to me why this is. I will range charge again on Saturday morning and again Sunday morning for a trip this weekend. Hope to see the widely reported range bump...but it's still discouraging to think that my standard charge used to be 242 miles and a range charge was 272.
24,500 miles, 14 months.

That's actually pretty darn good considering the mileage.

 

[islandbayy]

I don't think you are following what I'm describing. In your car, click energy on the 17". Then click average. The number displayed on the right is your estimated range.

Peter

PS, I'm still very interested to find out how to ask for a real solid number for predicted degradation from Tesla. As far as I know, you are the only person who has managed to get this info.

Ah, I see, yes, that is your estimated range based on the last XXX (Select 5mi, 15mi or 30 mi).


It was phone support, while going back and forth with engineering. Engineering pulled the info, phone support did not have it. they were trying to figure out why my vampire losses doubled during the 5.6 firmware.

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OAT was very cold, around 10F, in the garage it was probably around 50-55F (kept warm with a space heater).

I'd chalk that up to temperature still. Do you have a Supercharger around you?

 

[AmpedRealtor]

For me, Balancing is regularally, as I range charge often. In my opinion, i'd say Monthly with Lithium.
Having a balanced pack is important for longevity as well. In a out of balance pack, the lower voltage cells are getting cycled deeper then the higher voltage cells, causing them to go to a lower state of charge.

I was under the impression that every cell in the battery pack was individually heated/cooled and monitored. If that's true, why would the BMS not be intelligent enough to know when certain cells are out of balance, etc.? The fact that Tesla has not stated that packs need to be balanced would indicate that they are already handling this behind the scenes, and without the customer's need to intervene. I would be shocked if Tesla allowed any individual cell to drain or fill into a range where it would damage the cell or become detrimental to the cell's long term capacity or viability.

I'm confused by the question-reponse-thanks about how often one should balance the pack. No recommendations from Tesla that one should do it at all (if anything, conflicting advice from them to not max charge unless needed). Folks seem to do it to see what absolute max they can squeeze out of the battery, to try to determine whether it appears they've had capacity degradation, etc. Not to help the battery itself.

^^ this

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One other question... what's a P120?