How much is too much (charging to 100%)?

[Teefal]

Had my Model Y for six weeks. I've mostly been a good boy and not charged past 80% and rarely at superchargers. I've also not let it get below 20% except once. But I'm curious and want to learn, so charged to 100% three times at home and six times at superchargers.

The car started off showing 316 miles of range (official amount). My final big test I supercharged from 5% to 100%, after which the rated range showed 309 miles.

Did I squander 7 miles (2%) of my new car's range because I maxed out the battery 9 times?

Is it really that sensitive to supercharging at the high and low ends? Or was the 316 never real to begin with (my initial 100% charges hit 316 again, and later ones hit 313, etc)

Anyway, we supposedly got a 10 mile range boost tonight and I'm afraid to test it because I'll ruin as much as I gained by going to 100%.

 

[jcanoe]

The displayed range is just an estimate. Change the display option to show % of battery charge instead of estimated miles and that will give you an accurate readout. If you are at a SC and charging past 80% you are doing it wrong, wasting time and tying up a charging spot. It is not recommended to charge beyond 90% on a regular basis; 70% to 80% for daily use is better for the long term health of the battery pack. On the low end of the battery state of charge try and stay above 20% unless you have no way to charge. Charging to 100%, on occasion, just before you drive off will not cause any issue. Don't let the vehicle sit charged to 100% for a prolonged period.

SuperCharging does stress the battery pack more than other charging methods, i.e. 120V charging and 240V charging. When a lithium ion battery is charged at or above 1C (where C is the capacity of the battery being charged) this will shorten the useful life of the battery (the battery will eventually not be able to retain as much energy as when new.) SuperCharging, whether at 120kW or the newer 250kW charging rate can be well above 1C and in some cases almost 3C, although only for short part of the charging cycle. Supercharging is a great option, enables longer trips but frequent use of SuperCharging can result in Tesla throttling back the maximum SuperCharger charging rate if Tesla determines that as a result of frequent SuperCharging the battery pack in the vehicle can no longer safely charge at the higher charging level.

 

[Teefal]

Thanks. I knew all this already. My charges were experiments to see how fast supercharging happened at different levels (using teslafi, etc)

My question is whether 9 charges screwed up my car with only 2k miles. Kind of like the don't drive over 50mph for 100 miles thing for ICE cars

 

[jcanoe]

There is no way know for certain if your experiment affected the battery but it probably did no harm. I ignore the estimated range, choose to display the battery state of charge as a %. I charge whenever the state of charge (SOC) drops below 50%. I normally charge to 80% but would charge above 90% if leaving on a trip.

 

[Zoomit]

My question is whether 9 charges screwed up my car with only 2k miles.

Emphatically, no. You did not.

 

[Twiglett]

Tesla batteries are officially a black art.
There are many posts on here from folks claiming emphatically that their explanation is for sure the real one. There have been a seemingly equal number of posts from others expressing wonderment at how people can be so stupid as believe such nonsense. But I reckon they're all wrong, or at best they're accurate for the software released at the time. As they release a new version about every two weeks . . . .

For a sample size of exactly one car - my Model 3 was delivered to me with a projected 100% range of 309.8 miles.
Now, after 36k miles is has dropped as low as 288 and is currently projecting 310.43 miles for a slight increase on delivered range.

I honestly think it's exercise in futility to try predict what the BMS is doing with whatever software version you car is on. I'm sure some folks like to think that the BMS is somehow left untouched even when every other car system is updated - the chances of the BMS doing the same thing now as it was doing back in 2018 is not high

I'm happy to categorically state - I have no clue

 

[Teefal]

Ok, so I got one "probably no damage" from a guy who never supercharged or went over 90%, one emphatic no damage, and one no one really knows. I guess I'll take the range boost and stop worrying. At least 80% is again over 250 miles.

Thanks.

 

[LoudMusic]

I keep my battery between 10 and 85 %. Going that low on road trips is how you get the most out of the SuperChargers. I've visited about 20 SuperChargers in two and a half months, and we've put 5900 miles on it so far.

My understanding is that basically all lithium based batteries have an initial drop in capacity after a handful of cycles. 1 or 2 %. For us that could be 6 miles of range right there. Then it levels off for a long period, another hundred+ cycles, before beginning to lose capacity again. I unfortunately have no links to reference There were some great Model S capacity charts back in the day.

High power charging apparently accelerates capacity reduction, but we're talking hundreds of long sessions.

Furthermore, Tesla have made significant advances in battery management to minimize that effect. The charging curve is a good example. The vehicle only pushes high power to the battery when the battery can accept it, and tapers off as the battery fills. Along with temperature management.

Also, doesn't the estimated range fluctuate based on recent energy consumption? Maybe you were driving like a hooligan on the way to the charger

I think you're doing fine.

 

[CyberGus]

There was a thread here somewhere (can't find it, damnit) citing Tesalfi's fleet data, showing that all Teslas experience the most degradation initially. The rate of decline quickly tapers off.

So it seems like there's a "break-in" period what will lead to some range loss, regardless of behavior. But this is short-lived, and does not represent the rate of decline over the life of the pack.

 

[Teefal]

Thank you both. Two percent off at the start is easier to hear than damn-son-why-did-you-supercharge. Kind of makes me wish they'd factor that 2% in the rated range and say, initial range may be higher.

But, marketing.

 

[silverstoned83]

Based on your description, you've done no damage to your battery in my opinion.

From my understanding, the estimated range at a full charge becomes somewhat inaccurate over time, especially in the M3 and MY, because of the way it performs the calibration process. This process takes several hours to complete, unlike the MS and MX, and it often gets interrupted due to how much longer it takes. In order to have the most accurate range estimate, the calibration needs to be done at varying states of charge, which is easier said than done when you consider that it does not begin until it's asleep and can take a few hours to complete. This leaves a minimal amount of calibration points at various states of charge, except for the calibration that would often be completed successfully after the charge is complete. The problem is that without more calibration points, the battery management system loses calibration with the packs true capacity/range.

I highly recommend checking out the thread below, which goes into more detail about what I'm trying to explain.

How I Recovered Half of my Battery's Lost Capacity

 

[MorrisonHiker]

The temperature can affect the estimated range as well. Has the temperature gotten a lot colder recently?

Depending on the weather during the year, I noticed that my S90D would estimate a full charge between 289 (winter) and 295 (summer).

 

[pt19713]

The majority of the degradation will be in the first 10k-15k miles so it's something you'll have to accept. Try not to worry about it too much. As long as the batteries charge and discharge, it will happen. Try not and micromanage every decision you make.

 

[Matsayz]

Thanks. I knew all this already. My charges were experiments to see how fast supercharging happened at different levels (using teslafi, etc)

My question is whether 9 charges screwed up my car with only 2k miles. Kind of like the don't drive over 50mph for 100 miles thing for ICE cars

Ok, so I got one "probably no damage" from a guy who never supercharged or went over 90%, one emphatic no damage, and one no one really knows. I guess I'll take the range boost and stop worrying. At least 80% is again over 250 miles.

Thanks.

Thank you both. Two percent off at the start is easier to hear than damn-son-why-did-you-supercharge. Kind of makes me wish they'd factor that 2% in the rated range and say, initial range may be higher.

But, marketing.

You seem like you’ve read a couple things but don’t want to accept what’s been conveyed. Go read the Battery section for the other Tesla vehicles on the forums, you’ll see it’s all normal.

We all get it, the range drops in these vehicles from the advertised X amount, but did you have the same concern when your previous car wasn’t getting X amount of mpg’s? Probably never thought about it did ya? You leave every morning for work with a full tank, appreciate that fact and stop thinking about miles you haven’t actually lost.

Plug it in every day, set it to a number between 50-90% and enjoy updates about every two weeks making your car better than the day you bought.

Here’s our Model Y, info from TeslaFi (grain of salt). It’s supposedly “only” getting 288 (298 now w/ 2020.40.8). I’m changing the daily charge rate to 80% now that Summer is over here in Vegas and my wife’s job location is closer but meh, it’s just fine. My Model 3 SR+ is getting 8 less miles a year later, meh, enjoy the car man don’t worry about the number.

Oh and you’re in PA so don’t freak when your daily range drops through the floor this winter...

 

[Srad600Volt]

The displayed range is just an estimate. Change the display option to show % of battery charge instead of estimated miles and that will give you an accurate readout.

How is this achieved, I do not see that option? Thanks.

 

[jcanoe]

How is this achieved, I do not see that option? Thanks.

To access the option to display the battery state of charge (SOC) go to the Summary of Controls Menu; this option can be found under Display options. (Reference Model Y Owner's Manual page 118.) The option to switch between estimated remaining driving range and % of battery pack charge can be found under the Display options. Truly this display option should toggle simply by tapping battery icon instead of having to hunt for it.

 

[Rocky_H]

Change the display option to show % of battery charge instead of estimated miles and that will give you an accurate readout.

That's not being accurate; that's just sticking your head in the sand. I suppose you could say it's being technically "accurate" to just have a fuel gauge that says, "There is some fuel in there." But that's not really informative. The % is just a "fullness" reading, but doesn't say anything about how much energy that actually is. If the car's battery eventually gets really worn out and loses a third of the original battery capacity, the % will still say 100% when it's holding all the energy it's capable of storing, so that doesn't really tell you much, but does prevent people from seeing something that might make them concerned.

 

[pt19713]

so that doesn't really tell you much, but does prevent people from seeing something that might make them concerned.

That's what jcanoe is suggesting to avoid worry about 7 miles.
It could be something as simple as doing a battery calibration, or it could be the battery degradation that everyone gets at the initial portion of ownership. There's no avoiding it. Set it to percent and not worry about it.

 

[GOVA]

Those are always estimates. Keep driving and charge as needed. You will be fine.

 

[Darmie]

If sentry mode is used often, the battery can't properly balance and therefor can not get an accurate reading of full battery voltage.