Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

how bad for the battery is supercharging?

This site may earn commission on affiliate links.
1. I think there are a lot of self-righteous posters in this thread. If I'm going to the mall, which has a SpC, I park at the SpC instead of taking a regular spot. If I'm going to the store that has a charger, and it's free, I park at the charger instead of using a regular spot. Do I need to do it? No. Am I saving something? Maybe 1-2 cups of coffee a year. Why do I do it? Why not, the chargers are there. If I don't use them, no one will.

I wouldn't explicitly go out of my way to charge though. And it doesn't sound like OP is either.

Also, before I decided to make the plunge and get home charging, I'd drive up to the mall and charge there a couple times a month (usually I could do all my charging at home at 120V, those few times when something comes up, I'd be low on charge). Was I using the system in a way it was not meant to be? Maybe. But it's also not explicitly against the rules, so... whatever.

B. Don't overthink this too much. I charge to whatever level I need, whenever I need. If I need 100%, I don't think twice about it. If I need to SpC, I don't think twice about it. I think people are way overthinking this.

The battery will degrade with time and use regardless, so by putting in a ton of effort you might save yourself a tiny percentage of that degradation (which is already low) a year? Eh... not worth the effort.
 
Last edited:
I'm 99% sure it doesn't charge the 12V battery from the wall socket, only from the big battery and only when the contactor is enganged which is, I believe, during 1) driving and 2) charging (of the big battery). So in other words you plugging in the car to the wall socket when you are above your set charge limited accomplishes nothing. The only two instances where it would turn out smart to do this is:
1) You realize at night that you will need a 90% or 100% charge the next day, through the remote app you bump up the charge limit and the car starts charging (without the need for you to go to the garage to physically plug in)
2) Something happens and you need to suddenly leave, leaving the car unattended for a long time, during which the vampire drain eventually makes you reach your charge limit.

I use it for scenario #1 and also to pre cool the car as @HankLloydRight mentioned. I didn't know it would have no impact on the 12V but it sounds like it doesn't hurt either.

Ok, this doesn't make sense to me (not that it doesn't make sense at all, just doesn't to me), but this seems like overkill. If you are plugging in every night anyway, I would just set the charge to 70% or 80% and leave it at that all the time -- except when I need to do a range charge for a long trip.

I leave mine set to 70% most of the time, and plug in every day.. some days it charges for 30 minutes, other days maybe an hour or three depending on how much driving I've done the day or two before (yes, sometimes I forget to plug in and it doesn't charge that night).

I'm not sure I see the logic is resetting it to 90% once a week just so it doesn't "charge every day". When Tesla said "a plugged in Tesla is a happy Tesla" I think that's what they meant -- that recharging to a set % every night is OK.

I've had extensive discussion on this topic with Tesla based on a complaint I had that I was rapidly losing Rated Range from the day the car was delivered last September until last December. I'm not going to get into the details of that because it's complicated and probably boring for most people but the end result was that the advice from Tesla (via an email from an engineer to the Manager of the SvC) was that for my limited daily driving habits and keeping a high SOC and then just using 2 or 3 percent of that was causing the algorithm to go off. He asked why I was charging up to 90% every day instead of letting it use up more and charging less frequently. I told him that's what I was told to do when I picked up the car. They recommended that I run the battery down below 10% and then do a trip charge to balance. After that and a couple of firmware updates I got almost my entire Rated Range back to what it was when new. So, it worked for me significantly better than daily 90% charging had done.


Where did you speak to a Tesla engineer? I find this alleged advice very odd since anyone with a basic knowledge of how lithium ion batteries work would never say cramming in electrons is good for the cathode in a lithium ion battery. It makes no sense since the more electrons you put into a lithium ion battery (after about 80% especially), the more the cathode degrades. Now, I know Tesla's 100% is not each individual cell battery's actual 100%, but it's high enough that Tesla tells you not to go past their 90% unless needed for range. They say that because high charge levels hasten capacity loss.[88]

How can you know good results after 3 months? It takes longer than that to start to notice cathode degradation. That like saying my three year old child is nice and healthy and will live a long life even though I feed him McDonald's every day.

I'll let the "alleged advice" comment slide but as stated above it came from someone I trust at Tesla relaying comments in an email about my situation from a Tesla engineer. I believed him and, most importantly, it worked. Last month I went on vacation for a couple of weeks and as a test went back to my original charging method of daily 90% charging. When I got back my Rate Range and dropped by mile or two. After another balancing it came back and I resumed using up the battery to 50/60% and then charging back up to 90% method as stated in my post. I do not think putting 30% charge in the battery is "cramming electrons" and therefore bad for the battery but perhaps I'm misunderstanding what you are trying to say here.

Agree 3 months is not a long enough tests but given that I started with 256 miles of Rated Range at 90% and lost 10 miles within 12 weeks originally and that was a continuing pattern the fact that I've regained all but two miles (my current Rated Range is a consistent 254 with Range Mode off for 12 weeks) by following the advice I was given tells me it's going in the right direction. I think since this seems to be working and it is the advice from the manufacturer i should stick with it and see where it goes, agree?

I agree the plugging in and not charging routine doesn't make sense and it isn't best for the battery. If you only do enough driving every day to knock off 7% of your charge, then set the charge to 60% and leave it there and plug in every night. You'll go from 60 to 53% daily and back up to 60 every night when you charge. This is better for the battery than exercising 40% of it's range weekly plus it's better to not charge to 90% unless you have to. Yes 100% is WAY worse than 90% but 60% is still better than 90% as long as you don't need to dip too low.

Also, say you do 4 cycles of 50 to 60% over 4 days(i.e. 1 10% range cycle per day). This is better for the battery than 1 40% range cycle every 4 days.

This seems to be contrary to what the manufacturer advises and most of the time I do not use even 7%, more like 3% on average unless I take a trip and since this method didn't work for me when I was doing the same thing but at 90%.
 
Last edited:
  • Like
Reactions: Johan
I'll let the "alleged advice" comment slide...

Sorry, that does sound bad. I didn't mean to insinuate that you were not told that advice. I meant to suggest that the advice itself, which you said was good advice, was "allegedly" good advice but, in fact, was bad advice, at least from my research of how lithium batteries work. I apologize for the rude way I tried to say that.

I do not think putting 30% charge in the battery is "cramming electrons" and therefore bad for the battery but perhaps I'm misunderstanding what you are trying to say here.

It was the "charging to 100% every month or two" that you do (without needing to for range) that I say is bad for the battery -- that is what I was referencing with "cramming electrons" -- not the 30% issue that you raise above. If you don't need 100% don't do it is the best advice, and if Tesla says anything else then they are going against the established research on this issue:

How to Prolong Lithium-based Batteries - Battery University

"Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this."
 
In fact if you do two or three range (100%) charges in a row, the car gives you a warning message about battery degradation.

The advice I've heard (and follow) is that a 100% charge is OK once in awhile if you need the range, but you must use that energy as soon as possible. It's not the charge to 100% that does the damage, it's leaving it a high SOC that does due to internal heat buildup.
 
  • Like
Reactions: Jeff N
Sorry, that does sound bad. I didn't mean to insinuate that you were not told that advice. I meant to suggest that the advice itself, which you said was good advice, was "allegedly" good advice but, in fact, was bad advice, at least from my research of how lithium batteries work. I apologize for the rude way I tried to say that.



It was the "charging to 100% every month or two" that you do (without needing to for range) that I say is bad for the battery -- that is what I was referencing with "cramming electrons" -- not the 30% issue that you raise above. If you don't need 100% don't do it is the best advice, and if Tesla says anything else then they are going against the established research on this issue:

How to Prolong Lithium-based Batteries - Battery University

"Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this."

No worries on the "alleged" we're cool. Yes the advice about the trip charge "every month or two" did, in fact, come from Tesla as a means to keep the Rated Range calibrated and it works but I agree it's contrary to what I know also.
 
Wow - I've been pinged to the left;ponged to the right. When my MS arrives, will there be a manual that says "Tesla says charge this way". Is the best information about how to operate my car sourced in these great conversations? I see the honest contradictions from informed sources and end up ping-ponged.
 
This seems to be contrary to what the manufacturer advises and most of the time I do not use even 7%, more like 3% on average unless I take a trip and since this method didn't work for me when I was doing the same thing but at 90%.

Exactly what are you saying is contradictory to what the manufacturer claims?????

If you only use 3%, great, but stay plugged in and charge it every if you can so you exercise a smaller charging range of the battery.
 
Wow - I've been pinged to the left;ponged to the right. When my MS arrives, will there be a manual that says "Tesla says charge this way". Is the best information about how to operate my car sourced in these great conversations? I see the honest contradictions from informed sources and end up ping-ponged.

This guy is one of the industry's foremost experts. Watch this video and you'll learn a ton + stuff you don't need to know :)

 
  • Like
Reactions: HankLloydRight
Exactly what are you saying is contradictory to what the manufacturer claims?????

If you only use 3%, great, but stay plugged in and charge it every if you can so you exercise a smaller charging range of the battery.

You say charge to 60% daily in this scenario Tesla says 90% is best. You say charge daily even if it's a small amount Tesla told me otherwise. Wouldn't you say that is contradictory?
 
  • Like
Reactions: SSD420
Isn't this more of a function as to where the physical maximum charge is compared to where the manufacturer defines it? I.e., 100% on the display may be 90% of physical capability, and perfectly safe? Or the display might show 100% capacity whereas, really, the pack has been eating one third into its, say, 10% pre designed reserve?

Charging every evening to 100%, my iPhones 3, 4 and 5 handed down to family use have no battery issues that were not there from day 1. Manufactured in 2009, 2011 and 2013. Those Li batteries pose fewer problems in real life than in theory?
 
I've read the research, watched the videos, own a Leaf (no thermal management) and a Tesla. This is what I recommend: (1) Put the charging slider anywhere in the daily driving range that works for you, and that you feel comfortable with, and don't think twice about it. Anywhere in that range is fine. (2) Plug it in whenever you can because shorter cycles are best for lithium ion batteries. Longer (or "deeper") cycles cause faster degradation. Plus, the car will use the wall, rather than the battery, to operate certain things, causing less battery wear. For these reasons, Tesla says:

Battery Reminder.jpg


(3) Whenever you need more range than the daily driving range, charge it to 100% (and don't be concerned about doing so!). The only thing to think twice about is making sure you don't let it sit too long at 100%. The ideal is to drive it right when it hits 100% but that's not always realistic and leaving it sit for a few hours at 100% isn't something to be concerned about.

That's it. Don't overthink it. As someone here said some time ago, it's a car, not a bomb. Don't sweat it.
 
Last edited:
You say charge to 60% daily in this scenario Tesla says 90% is best. You say charge daily even if it's a small amount Tesla told me otherwise. Wouldn't you say that is contradictory?

Tesla told you not to charge every day????? Who at Tesla told you that?? They say 90% assuming people want the maximum range. They say 90% is ok to do every day. They did not say that is the best possible way to extend the battery life as long as possible.
 
Isn't this more of a function as to where the physical maximum charge is compared to where the manufacturer defines it? I.e., 100% on the display may be 90% of physical capability, and perfectly safe? Or the display might show 100% capacity whereas, really, the pack has been eating one third into its, say, 10% pre designed reserve?

Charging every evening to 100%, my iPhones 3, 4 and 5 handed down to family use have no battery issues that were not there from day 1. Manufactured in 2009, 2011 and 2013. Those Li batteries pose fewer problems in real life than in theory?

Yup, but 100% on an iphone isn't really 100%. If you remove an iphone battery that has been charged to 100% and then charge it on a lithium ion hobby charger, it will take another 20% or so.
 
How does one collect this "i'm down" data? Charge to 100% and read range - do this on the first of every month and start a log?
{see, I just gotta have something complex to do with this new battery...}

1. The only real way to see is not that great for the battery, so very few do it (discharge to zero and charge to 100% a few times).

2. When you do a range charge set the display to Ideal miles and take the value and divide by 300 (for an 85 kWh battery).

3. If you're just doing a daily charge, set the display to Ideal miles take the 90% number divided by 90 times 100 and divide the result by 300.

Ideal miles seems to be more constant than Rated Range, which they fiddle with all the time.
 
Tesla told you not to charge every day????? Who at Tesla told you that?? They say 90% assuming people want the maximum range. They say 90% is ok to do every day. They did not say that is the best possible way to extend the battery life as long as possible.

One thing I've found is that if you ask 100 different Tesla personnel you'll get close to 100 answers.
 
That's it. Don't overthink it. As someone here said some time ago, it's a car, not a bomb. Don't sweat it.

That's right. If you don't want to overthink it, then do what Tesla says and it's *nearly* as good as you could get.

When they say 90% is fine it doesn't mean they think it's best. If 70% is fine for your daily needs, set the slider to that and leave it there.

If you're the type that just can't handle any planning at all and every now and then you need more than 70% and if you can't remember the night before that you'll need that, then just set it to 90% and leave it there....even if it isn't quite as good for the battery as leaving it at 70% but it probably won't make a difference of more than a few % degradation over the life the the car.

It's too bad the 12v battery can't be charged from shore power.
 
  • Like
Reactions: Canuck and Jeff N
Tesla told you not to charge every day????? Who at Tesla told you that?? They say 90% assuming people want the maximum range. They say 90% is ok to do every day. They did not say that is the best possible way to extend the battery life as long as possible.
That's correct. The SvC Manager said with my pack it would be better to let the battery run to the mid ranges 40-60% before charging it back to 90%. My compromise was to set the daily charge to 50% as stated upthread.
I've learned through other users experiences that the Tesla DS's were trained or scripted to tell customers what I was told and that was to charge to 90% daily. They didn't say it was to extend the battery life or any other reason just that 90% was best. I'm sure you've seen other people say that too. Anyway, there's no sense arguing, Tesla is known to have communication issues and are often inconsistent in what they tell owners and there's dozens of views on this forum on what is best. My view is there may not be one right answer just whatever works best.