Losing 2% charge over night

[455dan]

If your Tesla Model Y is new and you regularly maintain the battery state of charge between 40% and 50% the battery management system (BMS) does not have much data to work with when determining the state of the battery. Periodically charge to 95% or higher and drive (over multiple days if needed) until the battery state of charge is at or below 20%. At least some of the time park with Sentry mode set to be off so that the BMS can perform the open cell voltage measurement.

Interesting, I have about 3300 miles on the YP but have never let the battery get below about 35% usually charge to around 75% unless going on a 200 mile big city trip. Almost always just plug the car in when home and charge at 48 amps.
So it is a Good idea to at least every so often let the battery get down to under 20 % so the BMS can do some calculations??

 

[jjrandorin]

Why are you charging to only 50% ?

Short answer, because of @AAKEE 's data driven posts on the subject of battery maintenance, how to minimize degradation, etc. For more than that, you can search TMC for posts by @AAKEE who has provided a ton of information on this topic, across multiple threads (many multiples of threads).

 

[jcanoe]

Interesting, I have about 3300 miles on the YP but have never let the battery get below about 35% usually charge to around 75% and plug the car in when home.
So it is a Good idea to at least every so often let the battery get down to under 20 % so the BMS can do some calculations??

If you want to provide the BMS with more data for the BMS algorithms that are used to determine state of charge then charge and drive over a wide range. There is nothing special about 20% except below 20% Sentry mode and Cabin Overheat Protection will be automatically disabled. Leave Sentry mode set to Off (also Smart Summon if equipped with FSD) at least some of the time while parked for more than a couple of hours so that the BMS can perform open cell voltage (OCV) measurements. Do this and you may observe the estimated range increase by ~5%. The actual range will not increase or recover, what happens is the BMS algorithms become better (more accurate) at estimating the state of the battery over a wide range of charge.

 

[Abraham]

Hmm, yes I’d agree with the others that 2% is normal, however you said you were plugged in… is that normal? I don’t think mine has ever dropped while charging..

 

[GtiMart]

If the drop is NOT because of an energy expense, yes it could happen even while plugged. For example if the battery is at 50% (based on voltage) and the target SOC is 50%, the car might show 48% due to a cooler battery and it would not charge because the battery is at 50% (based on voltage).

 

[Abraham]

If the drop is NOT because of an energy expense, yes it could happen even while plugged. For example if the battery is at 50% (based on voltage) and the target SOC is 50%, the car might show 48% due to a cooler battery and it would not charge because the battery is at 50% (based on voltage).

I see, that makes sense, thank you.

There is something else I’m still confused on- OP said they set the limit at 50%, how come it didn’t come to near that in the morning?

 

[GtiMart]

10am departure, checked at 6:30, there's only around 12% to charge. It won't take 3.5h, I say it's normal that it hasn't started yet.

 

[Abraham]

10am departure, checked at 6:30, there's only around 12% to charge. It won't take 3.5h, I say it's normal that it hasn't started yet.

Ah gotcha, thank you. I’m only on a 120v outlet so that threw me off heh.

 

[AAKEE]

Why are you charging to only 50% ?

One example:

I recently sold my 2 1/2 year old M3P to a Swedish EV car trader. They evaluate the batteries.

My car is about the oldest M3P refresh in Sweden (got it a few weeks after the forst arrived). It has 66000km on the ODO.
Have been using low SOC (55%) formdaily driving.
According to this Company, my M3P has 94.4% State of health (SoH) on the battery.
The five other M3P refresh (2021-2022) with the same battery has all lower ODO, down to 1/3 of mine, and is built later.

These have 87, 87, 88, 90 and 93% SoH on the batteries.
These cars where driven in about the same climate as mine.

 

[flixden]

10am departure, checked at 6:30, there's only around 12% to charge. It won't take 3.5h, I say it's normal that it hasn't started yet.

Yeah, that. It had not started charging yet, as expected.

 

[ewoodrick]

One example:

I recently sold my 2 1/2 year old M3P to a Swedish EV car trader. They evaluate the batteries.

My car is about the oldest M3P refresh in Sweden (got it a few weeks after the forst arrived). It has 66000km on the ODO.
Have been using low SOC (55%) formdaily driving.
According to this Company, my M3P has 94.4% State of health (SoH) on the battery.
The five other M3P refresh (2021-2022) with the same battery has all lower ODO, down to 1/3 of mine, and is built later.

These have 87, 87, 88, 90 and 93% SoH on the batteries.
These cars where driven in about the same climate as mine.

Mine 5 year old Model 3 just showed 93.5%. I regularly charge to 80-90% and have gone to 100% many times.

Your point is?

 

[GtiMart]

...are you really going to argue with AAKEE? Have you read all the information he provided here and all the tests he's done? Explaining why it's good to keep your charge lower doesn't mean that a higher charge will systematically destroy your battery. You're inferring things the wrong way.

 

[ewoodrick]

...are you really going to argue with AAKEE? Have you read all the information he provided here and all the tests he's done? Explaining why it's good to keep your charge lower doesn't mean that a higher charge will systematically destroy your battery. You're inferring things the wrong way.

I was stating a point similar to what he did.

All I was seeing in his numbers was a pretty standard deviation. There was one that was within 1.4% (5 miles) of his "heavily managed" car.

I can drive over 200 miles whenever I want. He can't.

In his WORST CASE, the car had 24 miles less than his. Is it really worth the trade-off? Best case

So yeah, you may could get a FEW more miles doing it his way. Does it really matter for the trade-off?

SO MANY folks show how doing something one way can make a difference, VERY FEW actually quantify the results.

It doesn't seem to be worth it to me.

 

[AAKEE]

Mine 5 year old Model 3 just showed 93.5%. I regularly charge to 80-90% and have gone to 100% many times.

Your point is?

How did you determin the 93.5% ?

Most often its big differences how we do this.

Is it a M3LR 2018, then?
Range at 100% or did you do the energy graph calc.

My M3P has lost 3% range, and the others I refered to a lot more.

Different batteries behave different and the 82.1kWh do not reach even close to 82.1 in real life. This set the Numbers of a lot.

For the old 77.8 kWh I think it was normal to reach beyond 77.8, maybe 79 kWh (learned from this forum, it was before my time).
So you can loose 3 kWh ( = almost 4%) before the range drops.

 

[ewoodrick]

How did you determin the 93.5% ?

Most often its big differences how we do this.

Is it a M3LR 2018, then?
Range at 100% or did you do the energy graph calc.

My M3P has lost 3% range, and the others I refered to a lot more.

Different batteries behave different and the 82.1kWh do not reach even close to 82.1 in real life. This set the Numbers of a lot.

For the old 77.8 kWh I think it was normal to reach beyond 77.8, maybe 79 kWh (learned from this forum, it was before my time).
So you can loose 3 kWh ( = almost 4%) before the range drops.

I let it charge to 100%, 290 miles from an original 310 or 311 car.

 

[AAKEE]

I was stating a point similar to what he did.

All I was seeing in his numbers was a pretty standard deviation. There was one that was within 1.4% (5 miles) of his "heavily managed" car.

I can drive over 200 miles whenever I want. He can't.

I can, as there is Superchargers in range in all four main directions. ( also other brands of 200kW chargers in my town if needed).
Havent had an issue with the range even once in 2 1/2 years.

In his WORST CASE, the car had 24 miles less than his. Is it really worth the trade-off? Best case

The difference is that I had 492-495 km the last Full charges (15-17km loss/ 3%), while these other cars in Sweden had 464km at best, 449km at worst (9-11% range loss)This is loss in indicated range that is about 3-4 times more than my car.
These cars had less miles and is newer. A few of them was 2022 so much younger.

In the longer term the difference will be larger.

SO MANY folks show how doing something one way can make a difference, VERY FEW actually quantify the results.

I have, and I also have the research data from hundreds of battery research reports telling the same thing.

It doesn't seem to be worth it to me.

Of course this is a matter of personal choice. If you are going to keep the car very long, you might wanna keep the battery from getting tired. Look at model S batteries that are about 8 years. There is issues from tired packs.
—> For me it was worth it, and fun at the same time.

Just got me a Plaid and will do the same again.

I let it charge to 100%, 290 miles from an original 310 or 311 car.

Each mile is 245Wh.
290 miles is 71.1 kwh.
That battery was marked 77.8kWh full pack when new.
71.1/77.8= 9% loss.

From this forum I learned that it was not uncommon for the early batteries to reach 79 kWh, with this in mind your battery might be at 10% loss from the initial capacity.

 

[ewoodrick]

I can, as there is Superchargers in range in all four main directions. ( also other brands of 200kW chargers in my town if needed).
Havent had an issue with the range even once in 2 1/2 years.

The difference is that I had 492-495 km the last Full charges (15-17km loss/ 3%), while these other cars in Sweden had 464km at best, 449km at worst (9-11% range loss)This is loss in indicated range that is about 3-4 times more than my car.
These cars had less miles and is newer. A few of them was 2022 so much younger.

In the longer term the difference will be larger.


I have, and I also have the research data from hundreds of battery research reports telling the same thing.
View attachment 955727



Of course this is a matter of personal choice. If you are going to keep the car very long, you might wanna keep the battery from getting tired. Look at model S batteries that are about 8 years. There is issues from tired packs.
—> For me it was worth it, and fun at the same time.

Just got me a Plaid and will do the same again.

Each mile is 245Wh.
290 miles is 71.1 kwh.
That battery was marked 77.8kWh full pack when new.
71.1/77.8= 9% loss.

From this forum I learned that it was not uncommon for the early batteries to reach 79 kWh, with this in mind your battery might be at 10% loss from the initial capacity.

But I never had 317 miles to begin with (71100/245)

 

[ewoodrick]

I can, as there is Superchargers in range in all four main directions. ( also other brands of 200kW chargers in my town if needed).
Havent had an issue with the range even once in 2 1/2 years.

The difference is that I had 492-495 km the last Full charges (15-17km loss/ 3%), while these other cars in Sweden had 464km at best, 449km at worst (9-11% range loss)This is loss in indicated range that is about 3-4 times more than my car.
These cars had less miles and is newer. A few of them was 2022 so much younger.

Yes, there is loss. That's a given. No I'm not arguing your numbers. (Although I'd appreciate it if you didn't argue mine)

My point is that it's not really as big of a deal as your numbers suggest. And when you start with the 3-4 times worse stuff, that's not a good comparison. Give the facts.

You had 495km, the worse had 449km. That's not a huge difference. It is a difference.

And on both every day trips and on long distance trips, there really is no difference.

My point is yes, you can baby your battery and get maybe 10% more range (which you will never notice) or you can treat it the way that Tesla recommends and get essentially the exact same performance out of the car.

The difference being is that your method tends to scare the crap out of EV owners and prospective owners (You can only use 50% of the car's range or the battery will self-destruct. Yes, that is the way people hear your story)
Or they can hear Tesla's story and realize that the battery isn't anything to worry about.

There are posters on the forums that make other users feel bad that they are treating their battery badly and make them think that the lifespan of their battery is going to be significantly reduced, partly because of your numbers.

But in reality....

• Did you get a better selling price because of your numbers?
• How many times did 50km make a difference in your travels?

 

[AAKEE]

But I never had 317 miles to begin with (71100/245)

71100/245 = 290 miles. (Current, right?)

Themax range 310 is reached at about 76000 Wh, the same 245Wh/mile.

Whenbthe car is new and have higher capacity the car still shows 310. Each mile then contain more energy.

So initial cap, at least 77.8. Matbe up to 79.
Todatys capacity 71.1. Thats the base for the calculation.

You can check the current capacity if you like with the energy app procedure.

 

[AAKEE]

Yes, there is loss. That's a given. No I'm not arguing your numbers. (Although I'd appreciate it if you didn't argue mine)

I only argue them as I know the calculation is not right for degradation.

Lost miles percentage is not the same as lost capacity as the car hides about 2% or more in your car.

So to compare degradation, if we use lost miles on your, we need to use lost miles on mine. Still not compareble as the old panasonic often reached well above the marked capacity in the same time as the new panasonic never ever reach it. In most cases, at best 2% below.

But in reality....

• Did you get a better selling price because of your numbers?
• How many times did 50km make a difference in your travels?

I actually live in an area with long distances and very very cold weather (down to well below -30C)
Driving to my mother in law and all the relatives in winter time is 260km and it oftwn is -25C to -35C, there is no descent charges for the last 210 km and when se arrive we often need range to go visit people. In some cases it has beennon the margin to have enough for the visiting relatives, or the family cabin 45km further away.

Yes, I need the range until they build superchargers on that road.
(They recently did it on an alternate 1 hoyr longer drive, so Its possible to charge nowadays if I go the 1 hour longer drive).

I’m sure I had gotten more for the car with the better rabge as it is known on a swedish forum that it has low degradation.
Also all M3 / M3P that is delivered in euope start with a LG battery that has more or less the same capacity as mine.
The difference is that the new batteries will have much faster calendar aging than mine, so mine would be one of the M3P’s with the best range.

But, there was an opportunity to get a new Plaid for much less (about 10 grand and three years of free SuC) which I could not not keep the fingers from.
Had to do it quick and the “loss” from a quick sell was much less then 10 grand pkus the 3 years free suc