Frequent supercharging killing my battery range? Only 1800 mileage.

[darth_vad3r]

1 or 2 deep discharge damage battery longevity or chronic deep discharge?

This is like asking if 1 or 2 times in the sun without sunscreen gives you cancer, or chronically going out in the sun?

Or smoking.

It’s not the best for the battery, so it’s better to do it only when necessary if that works for you. Each time you do something bad for the battery it accumulates.

 

[Saghost]

Hi all, I'd love some advice here.

I have a Model 3 SR+ (well, technically it's a model 3 SR, but the software downgrade hasn't been pushed to me yet). I bought the car in May 2019 and only have 1800 miles on the car.

Previously, at 80% charge I have 192 miles. Today, at 80% charge at the supercharger, I saw only 190 miles as opposed to the usual 192 miles. I thought maybe I didn't put the slider exactly at 80%. I went back into my car and toggled the energy display in % vs miles, and at 173 miles it is 73% full, which translates to 237 miles of charge at 100%, instead of the 240 miles I expected.

I live near a supercharger, and since I have 5000 bonus miles I have to use up in 6 months, I charge almost exclusively (95% of the time) at the supercharger. I always only charge to 80% SOC when I'm at supercharger (or at home). I charge about once or twice a week. I almost always charge between 30-80% SOC. Only once did I charge to 100%, and only once did I let it go down to 19%.

I've searched threads on this site but I'm curious what others think. Is it a battery calibration issue, so should I charge it to 100% and drain to 20% and see if that fixes it? Is it a software update issue (I upgraded to 28.3.1 a few days ago)? Or is it a true battery degradation caused by frequent supercharging ?

I know it's not a whole lot of range loss at 3 miles loss, but I expected the degradation to be much slower, maybe like 3 miles loss at 10000 miles, not 1800 miles.

Should I be changing my charging practice? Leave it plugged in at night every night, or charge every few nights (keeping SOC between 80% and 30%)? Stop charging at Supercharger routinely?

I would love to hear opinions or advice.

Thanks

You've been mentioning 80% a lot, which makes me think you may not be charging higher than that.

The thing is, 80% is in the constant voltage section of the discharge curve, so the car can get confused about where that is pretty easily. 90% has a higher cell voltage so the BMS can clearly see it.

Try charging to 90% for several days and see what the prediction looks like - just this week I had it predict a 4 mile loss at 80% charge (stopped at 236 instead of the usual 240,) but when I stepped it up to 90% a couple hours later the loss was gone (stopped at 270 as usual.)

 

[Tam]

1 or 2 deep discharge damage battery longevity or chronic deep discharge?

Tesla battery is very robust so you should not hesitate to use it as needed.

What we are talking is like: when you don't need to leave it unplug, then why leave it unplug?

If we don't need to do a deep discharge, then why do we do it?

Thus, if I am on a road trip and the next Supercharger will require a deep discharge, then do it! No hesitation at all. Do it because we need it!

However, it is an abuse when we do a deep discharge because we are busy to go to work every day and we want to supercharge once a week which results in a deep discharge. Don't do it!

I would also consider an abuse to do a deep discharge not because of a road trip, but because I want to re-calibrate the battery gauge so I can feel good that I would gain few miles on the meter.

 

[Tam]

...You've been mentioning 80% a lot...

I think Tesla prefers you to charge to 90% as much as possible if you want to minimize calibration drift.

You can set below 90% but the calibration drift will be greater and Tesla doesn't think there's a greater benefit to set it below 90%.

 

[KrenGrl]

OP, expecting a 0.5% accuracy where there area also other variables ?

 

[BZM3]

Hi all, I'd love some advice here.

I have a Model 3 SR+ (well, technically it's a model 3 SR, but the software downgrade hasn't been pushed to me yet). I bought the car in May 2019 and only have 1800 miles on the car.

Previously, at 80% charge I have 192 miles. Today, at 80% charge at the supercharger, I saw only 190 miles as opposed to the usual 192 miles. I thought maybe I didn't put the slider exactly at 80%. I went back into my car and toggled the energy display in % vs miles, and at 173 miles it is 73% full, which translates to 237 miles of charge at 100%, instead of the 240 miles I expected.

I live near a supercharger, and since I have 5000 bonus miles I have to use up in 6 months, I charge almost exclusively (95% of the time) at the supercharger. I always only charge to 80% SOC when I'm at supercharger (or at home). I charge about once or twice a week. I almost always charge between 30-80% SOC. Only once did I charge to 100%, and only once did I let it go down to 19%.

I've searched threads on this site but I'm curious what others think. Is it a battery calibration issue, so should I charge it to 100% and drain to 20% and see if that fixes it? Is it a software update issue (I upgraded to 28.3.1 a few days ago)? Or is it a true battery degradation caused by frequent supercharging ?

I know it's not a whole lot of range loss at 3 miles loss, but I expected the degradation to be much slower, maybe like 3 miles loss at 10000 miles, not 1800 miles.

Should I be changing my charging practice? Leave it plugged in at night every night, or charge every few nights (keeping SOC between 80% and 30%)? Stop charging at Supercharger routinely?

I would love to hear opinions or advice.

Thanks

its the software adjusting to your driving habits. dont worry about it, just drive it and charge it when you need to. try turning your range indicator to percentage rather than actual miles in settings, might cool you down.

 

[vickh]

This is like asking if 1 or 2 times in the sun without sunscreen gives you cancer, or chronically going out in the sun?

Or smoking.

It’s not the best for the battery, so it’s better to do it only when necessary if that works for you. Each time you do something bad for the battery it accumulates.

good points. Even one bad sunburn can cause cancer. But as long it's not chronic it's relatively low probabilty. I guess lesson learned (it was on a trip when we were running low, not good for me or the battery

 

[Rocky_H]

its the software adjusting to your driving habits.

No, it's not. I know where you get this idea, because every other auto maker except for Tesla does that, which is where that nickname "Guess-O-Meter" comes from. But the rated miles number on that battery gauge of a Tesla never takes any driving history into account. It is a conversion of an estimated energy amount in the battery, scaled by a fixed consumption factor.

 

[M3SRdude]

You've been mentioning 80% a lot, which makes me think you may not be charging higher than that.

The thing is, 80% is in the constant voltage section of the discharge curve, so the car can get confused about where that is pretty easily. 90% has a higher cell voltage so the BMS can clearly see it.

Try charging to 90% for several days and see what the prediction looks like - just this week I had it predict a 4 mile loss at 80% charge (stopped at 236 instead of the usual 240,) but when I stepped it up to 90% a couple hours later the loss was gone (stopped at 270 as usual.)

Saghost. you're right. I've always charged to 80% because I thought it saves battery longevity. I've only charged once to 100%, and once to 90% for longer trips since I've owned the car.

I'm not so concerned about the BMS not displaying the correct charge, but rather I'm more concerned about the true underlying longevity of the battery itself. Seems like the consensus here is that the 3 mile drop that I found is a calibration issue rather than true range loss.

 

[Rottenapplr]

I relocated my 14-50 input specifically so I can step out of the car and plug in. My car is plugged 100% when I am at home. I charge whenever I want. I’m not gonna stress about mileage lost. It’s long range rwd so f it. I charge to 50-60% when I’m not using it. 70-80 for work. 90 for road trips.
I have the battery settings set to show percentages and not mileage b/c the computer is highly inaccurate and it’s really not worth my time.

 

[M3SRdude]

Since it sounds like you are interested in the subject, and you also mentioned that you searched the forums, did you see this particular thread that talks about battery degradation being scientifically explained? The poster of the video works in the battery industry. Watch the video that poster @Zoomit links to.

Battery Degradation Scientifically Explained

Back on topic of the thread... The manual on the car that is provided by tesla specifically says that there is NO BENEFIT in running the battery down, and then charging it back up. Its also very (very very very very) likely that you have no actual range loss, but have calculation in BMS (battery maintenance system) loss.

You said you searched the forums... so you should have seen pages and pages and pages and pages (and pages and pages and pages and pages) of posts about this topic. The "simplest" thing to do is what the company that makes the car tells you to do, if you can, and that is plug in when you get to your garage.

If you want to focus on getting that free electricity, thats up to you as well. People in the industry to design these type of batteries say that in general, more damage to the battery happens at "higher charge speeds" . Supercharging is "higher charge speeds". Its also "better" for the battery to keep it closer to 50% state of charge. No one knows what the ACTUAL long term effect on Model 3 batteries are from running it down and not plugging in, and then charging up every time you get to 20% or something. We dont know the actual long term effect from only supercharging. We just know that there will likely be some sort of measurable effect. it could be "measurable, but insignificant".

One thing I have noticed from reading most of those "pages and pages" I mentioned above. Far more people seem to have "issues" with rated range reporting when they dont plug in every day in their garage. This is not necessarily battery degradation, but rated range display inconsistencies. It still bothers people, and many more people that charge "every few days" seem to have it.

In my specific case, I have zero rated range loss in 12k miles. I charge to 90% I plug my car in every time it hits my garage (every single time, regarldess of distance driven). I drive 80ish miles a day round trip to work, and plug in when i get home. If I run errands, I unplug, go run my errands and plug back in when I get home. I use a tesla Wall Connector with a 60amp circuit and my car charges at 48 amps which is the max it can.

My 90% charge is still 279, and my 100% charge is 309 which is the best its ever been since I picked up my car (it was 306 when I picked up the car for 100% charge).

I personally believe that, because I plug in every day, and drive a "decent amount" every day, the BMS in my car has little issues calculating my rated range. There is almost assuredly nothing wrong with OPs car.

If you want to "keep the battery healthy for 7-8 years" then watch the video in that link, and make your decisions about what you are going to do based on what the science says. With that being said, its my belief that tesla has designed the battery around the fact that human beings are stubborn, and many are not going to listen to the specific instructions they put in the manual about how to charge the car.

I would imagine there will be a measurable difference at some point, but it will not be a significant difference (meaning that maybe if you supercharge for the first 2 years or something, maybe you "lose" 10 miles of range, and someone who doesnt, doesnt... to make up numbers). 10 miles means almost nothing in the range of this car over 5 years... and is no different than older ICE cars getting less gas mileage the older they get.... its just that people focus heavily on the battery because its "different'.

hey jjirandoran,

thank for that link. Good info from a legit sounding guy. Sigh. I've done my car some disservice. I sometimes drive longer distances, aggressively, up a long hill (many miles), blasting the AC, in 100 degree weather, and run the battery down to 30%, then plug in the supercharger and quickly charge to 80%, then head home. Heat, high charging speed, all bad for the battery.

I'm going to change the way I charge from now on. Saving that $20 a month is not worth degrading even 1% over 1 year.

I now have two questions. My daily commute is pretty short (<10 miles round trip), and I don't really care if the battery calibration (remaining battery mileage displayed) is off, but I'm really interested in the longevity of the battery.

1) Is it better to charge within (1) 65-75% SOC range, or (2) 80-90% SOC range? Would doing (1) noticeably improve battery longevity?

2) I have a NEMA 15-40 plug with mobile charger at home. I don't need to charge quickly, and my car is parked at home at least 12 hours a day. Should I dial down the charging amp from the 32amp max to let's say 20, or even 10amp and trickle charge it to improve battery longevity?

I'd welcome any thoughts on this.

 

[darth_vad3r]

I now have two questions. My daily commute is pretty short (<10 miles round trip), and I don't really care if the battery calibration (remaining battery mileage displayed) is off, but I'm really interested in the longevity of the battery.

1) Is it better to charge within (1) 65-75% SOC range, or (2) 80-90% SOC range? Would doing (1) noticeably improve battery longevity?

2) I have a NEMA 15-40 plug with mobile charger at home. I don't need to charge quickly, and my car is parked at home at least 12 hours a day. Should I dial down the charging amp from the 32amp max to let's say 20, or even 10amp and trickle charge it to improve battery longevity?

I'd welcome any thoughts on this.

Not sure it would make much difference on (2) since they are all WAY friendlier to your battery than DC fast charging at much higher power. See if any relevant posts on that thread?

For (1) I think closer to 50% seems to be the consensus. Again, see that thread... there may be some uber-crazy thresholds you might worry about for transitions?

I would pick 60-50% over 75-65% over 90-80% ... but bump up to whatever min. you need for a last-minute trip so you can still get to a supercharger in any direction with a nice buffer of say 20%.

Whether this will be *noticeable* or not is yet to be deterimined. It *might* be I figure, if I don't need to sit at 90%, and I don't care if the range looks "off" a bit in the interim, and it MIGHT help the battery ... why NOT leave it lower on a daily basis?

Through occasional longer-range use and dips down and charging up to 90% for a trip, the recalibration will let you know where you are "really" at once in a while, and for the rest of the time you can just not sweat the slight changes in the range.

That's my take.

 

[jjrandorin]

hey jjirandoran,

thank for that link. Good info from a legit sounding guy. Sigh. I've done my car some disservice. I sometimes drive longer distances, aggressively, up a long hill (many miles), blasting the AC, in 100 degree weather, and run the battery down to 30%, then plug in the supercharger and quickly charge to 80%, then head home. Heat, high charging speed, all bad for the battery.

I'm going to change the way I charge from now on. Saving that $20 a month is not worth degrading even 1% over 1 year.

I now have two questions. My daily commute is pretty short (<10 miles round trip), and I don't really care if the battery calibration (remaining battery mileage displayed) is off, but I'm really interested in the longevity of the battery.

1) Is it better to charge within (1) 65-75% SOC range, or (2) 80-90% SOC range? Would doing (1) noticeably improve battery longevity?

2) I have a NEMA 15-40 plug with mobile charger at home. I don't need to charge quickly, and my car is parked at home at least 12 hours a day. Should I dial down the charging amp from the 32amp max to let's say 20, or even 10amp and trickle charge it to improve battery longevity?

I'd welcome any thoughts on this.

All home charging is considered "slow" from what I understand. The only benefit of turning down the amps would be some lost efficiency.

Closer to 50% state of charge is "best" for long term battery health... but no one is suggesting that anyone set their charging to 50% for daily usage.

Also, as I mentioned, there may be a difference, it might even be a measurable difference, but it likely will have little effect on usage of the car. In your previous ICE cars (if you had them before, which I would assume most people who can purchase a new tesla have at least owned some sort of ICE car before) did you ever worry about the fact that 5 years in your MPG were down some 2 MPG or some figure on average?

Probably no.

That "i want to do everything I can to take care of the battery" is your range anxiety talking. You say you dont care about the BMS calculation but you actually do. Its going to drive you crazy watching that rated range number go down.. because you will always think you are doing something to hurt your battery. You will tell yourself "this is just miscalculation of the BMS..... isnt it???"

If you need to supercharge, do so, if you dont, then dont. If you are going on a trip, charge to 100%, if you arent charge to some set percentage that covers your daily drive plus mileage for emergencies.... 80% seems like a good number many use. I charge to 90% every day, and have zero rated range loss after just about 12k miles over 9 months.

Try to let it go and just plug in. If you enjoy digging into this stuff as some do, have at it, but your posts dont seem like you are enjoying digging into the numbers. They seem like you are razor focused on some mythical "maximum health of battery", where I doubt when you had an ICE car you were razor focused on "maximum health of engine". You likely did your regular maintenance (oil changes, recommended maintenance) and drove the car.

This isnt a rare porsche or something, its a car ment to be daily driven, and if for some reason your car has 10 miles less max range in 5 years, its not going to effect you at all... because you are almost never going to drive the car down to where that 10 miles makes a difference.

 

[gecko10x]

This isnt a rare porsche or something, its a car ment to be daily driven, and if for some reason your car has 10 miles less max range in 5 years, its not going to effect you at all... because you are almost never going to drive the car down to where that 10 miles makes a difference.

I'm not the OP, and for the most part I agree with you, however, some of us become a bit paranoid because we aren't seeing 10 mile loss over 5 years, but more like 10 mile loss in the first 6k miles!

So, I totally get where the OP is coming from. We see any change and want to know if it's "real" or a BMS calculation error, or Tesla intentionally handicapping our cars (this is my hunch, based on my personal data).

 

[KenC]

hey jjirandoran,

thank for that link. Good info from a legit sounding guy. Sigh. I've done my car some disservice. I sometimes drive longer distances, aggressively, up a long hill (many miles), blasting the AC, in 100 degree weather, and run the battery down to 30%, then plug in the supercharger and quickly charge to 80%, then head home. Heat, high charging speed, all bad for the battery.

I'm going to change the way I charge from now on. Saving that $20 a month is not worth degrading even 1% over 1 year.

I now have two questions. My daily commute is pretty short (<10 miles round trip), and I don't really care if the battery calibration (remaining battery mileage displayed) is off, but I'm really interested in the longevity of the battery.

1) Is it better to charge within (1) 65-75% SOC range, or (2) 80-90% SOC range? Would doing (1) noticeably improve battery longevity?

2) I have a NEMA 15-40 plug with mobile charger at home. I don't need to charge quickly, and my car is parked at home at least 12 hours a day. Should I dial down the charging amp from the 32amp max to let's say 20, or even 10amp and trickle charge it to improve battery longevity?

I'd welcome any thoughts on this.

I would think 1-1 would be best for battery longevity, ie 65% to 75% SOC. There's a thread by some battery expert, he details where the battery chemistry problems are, you can read that thread if you're interested. As for dialing back the AC amperage, no, that won't matter.

 

[Rocky_H]

1) Is it better to charge within (1) 65-75% SOC range, or (2) 80-90% SOC range? Would doing (1) noticeably improve battery longevity?

There is "best/most ideal", but that is always balanced with what is your own practical use needs. Sure, more toward the middle is more ideal, but you need to have enough range to use. As to the second part, "noticeably improve"? Maybe not. From the study data, it is not a linear improvement with every same sized step away from the edge. In other words, that first 10% difference away from the top makes a really big difference. The next 10% down makes a lot less difference. The next 10%, even less difference. So using 90 instead of 100 is the most bang for the buck and has gotten away from the most damaging stuff. 80 instead of 90--probably a bit more helpful, but probably not too noticeable. If you don't drive much, though, 80% is probably still plenty of range, so you wouldn't be inconveniencing yourself to get that little extra benefit.

2) I have a NEMA 15-40 plug with mobile charger at home. I don't need to charge quickly, and my car is parked at home at least 12 hours a day. Should I dial down the charging amp from the 32amp max to let's say 20, or even 10amp and trickle charge it to improve battery longevity?

No, that makes no difference. Supercharging is in the level of 100kW+. Any of this at home charging you are talking about is asking about the difference between like 7kW or 9kW. It's all so slow that those differences are unnoticeable from the battery's perspective. The only possible thing might be if you are using a mobile charge cable that is rated for maximum 32A, it could get kind of warm at that level, so turning it down a couple amps saves some heat loss and may let your cable last a little longer from less heat cycling of hot and cold.

That "i want to do everything I can to take care of the battery" is your range anxiety talking.

What?! No, of course it isn't. That doesn't make any sense--it's actually the opposite of range anxiety. This is people intentionally giving themselves less daily range on purpose. If they were worried about it, they wouldn't do that. I have no range anxiety about this at all, but I still like going for the 75% or 80% level simply because it's sensible. I do very little driving around town. This behavior is about: "This doesn't inconvenience my use of the product at all, but will give some long term benefit to making it last better." That logic isn't about electric cars specifically at all. I would make the same decision about how I use a piece of clothing or appliance or furniture or anything.

 

[jjrandorin]

Your right, I said "range anxiety" when I ment to say "anxiety". Specifically "anxiety over the battery". Thats what I was thinking but thats not what came out of my fingers when I typed it. thanks for the correction.

 

[darth_vad3r]

Your right, I said "range anxiety" when I ment to say "anxiety". Specifically "anxiety over the battery". Thats what I was thinking but thats not what came out of my fingers when I typed it. thanks for the correction.

Range anxiety — being overly concerned with if you have enough range for your driving needs.
Range display anxiety — being overly concerned with if the range displayed in the car is accurate, and if it is dropping is that permanent degradation or a temporary calibration issue.

 

[vickh]

Range anxiety — being overly concerned with if you have enough range for your driving needs.
Range display anxiety — being overly concerned with if the range displayed in the car is accurate, and if it is dropping is that permanent degradation or a temporary calibration issue.

Maybe we need therapists that specialize in EV disorders But that's what this forum is for ..

 

[Rocky_H]

Maybe we need therapists that specialize in EV disorders

Hmm... Speaking of "therapists", I could not believe the name that other car company picked for their electric car. It was small and not very capable, and they called it the "Smart ED". *ahem* Are you trying to get people to have negative connotations thinking about electric vehicles?!