Is it better for my car to spend more time at 50% or have shallower discharge cycles but spend more time at a higher state of charge.

[Owner4523]

Rhan

You will always be able to charge to 100% but each percent will be less worth.

The range indication by the battery symbol that you can use instead of % will drop.

For a 3 LR it might start at for example 358miles. (Just grabbing a number as I do not se your cars spec).
When you have lost ~2% battery capacity the range will start to decrease for a full charge. After loosing 12% battery capacity , you will have lost 10% of the range (as the forat 2% are hidden from displayed range loss).
In this case you still have 100% on a full charge but each percent give you 12% less range.

Thanks. Let's say you have 150 miles of range at 50%. If you battery lost 10% would you still have 150 miles at 10% or would just loose max range (if that makes sense.)

 

[AAKEE]

Thank you for all of this great info. I read somewhere that when you change to 100% you can physically see the battery swell or stress or something like that, which caused me to be a little anxious to change to 100 as I don't want to stress the battery casing or anything.

I’ll try not to get going on this but myths about lithium batteries in forums…huhh!

If you read or hear something about lithium batteries it’s actually a higher probability that what you read or heard is not true than it actually is true.

Here on TMC it actually starts getting better and better probability to read the truth!

 

[AAKEE]

Rhan

Thanks. Let's say you have 150 miles of range at 50%. If you battery lost 10% would you still have 150 miles at 10% or would just loose max range (if that makes sense.)

If the new car had 300 miles range, and 150 at 50% it would have 135 miles at 50% after loosing 10% displayed range.

 

[Owner4523]

@AAKEE - "
Low SOC is nice for the battery. It will not be bad for the battery to be at low SOC overnight, it avtually is better to have low SOC.

It is a really good choice to charge late so the battery spend more time at low SOC."

Is there any limit to this? If you arrive home at 10% is it ok to leave it that way over night? What about driving? Ok to drive under 20%

 

[AAKEE]

@AAKEE - "
Low SOC is nice for the battery. It will not be bad for the battery to be at low SOC overnight, it avtually is better to have low SOC.

It is a really good choice to charge late so the battery spend more time at low SOC."

Is there any limit to this? If you arrive home at 10% is it ok to leave it that way over night? What about driving? Ok to drive under 20%

I guess I already posted this chart:

You can see that 0% causes the least calendar aging. (0% is not completely empty but instead it is the point where the battery manufacturer says to stop discharging, so it is the safe low point).

Our Teslas use a 4.5% buffer so when we read 0% on the display the real SOC is 4.5%. For reasons other than the big lithium battery pack it is best to not go below the 0% on the screen, but down to that level is very safe for the battery. You might want to have a little extra margin if you drove a lot and charge a lot just before the parking, to allow for that the car has miscalculated the SOC ( overestimated the SOC). The risk is that the SOC is lower than the estimate and the car shut down the big battery. If you onow your BMS i well “calibrated” then the risk is small, and you can go lower.
On a 10 year old battery with possibly not that good BMS calibration, a higher margin would be recommended.

Imarrived at home with <2% a week back after towing a trailer. The car was parked with 1.75% for 5hrs or so; then the charging needed to be started for the next day. Normally it would have been started ~ 0300-0400, and if I haden’t needed much energy the day after I had let it Sleep at 1.75% until 0300.

I often leave my car with low SOC, single digit is not umcommon, and I regularly have it at 10-20% for a whole week at work.

Its ok to drive under 20% and the lower limit should be your personal limit notmto get range anxiety.

 

[Owner4523]

I guess I already posted this chart:
View attachment 1022645
You can see that 0% causes the least calendar aging. (0% is not completely empty but instead it is the point where the battery manufacturer says to stop discharging, so it is the safe low point).

Our Teslas use a 4.5% buffer so when we read 0% on the display the real SOC is 4.5%. For reasons other than the big lithium battery pack it is best to not go below the 0% on the screen, but down to that level is very safe for the battery. You might want to have a little extra margin if you drove a lot and charge a lot just before the parking, to allow for that the car has miscalculated the SOC ( overestimated the SOC). The risk is that the SOC is lower than the estimate and the car shut down the big battery. If you onow your BMS i well “calibrated” then the risk is small, and you can go lower.
On a 10 year old battery with possibly not that good BMS calibration, a higher margin would be recommended.

Imarrived at home with <2% a week back after towing a trailer. The car was parked with 1.75% for 5hrs or so; then the charging needed to be started for the next day. Normally it would have been started ~ 0300-0400, and if I haden’t needed much energy the day after I had let it Sleep at 1.75% until 0300.

View attachment 1022648

I often leave my car with low SOC, single digit is not umcommon, and I regularly have it at 10-20% for a whole week at work.

Its ok to drive under 20% and the lower limit should be your personal limit notmto get range anxiety.

Thank you for taking the time to share this helpful information!

 

[LostVector]

Thank you for all of this great info. I read somewhere that when you change to 100% you can physically see the battery swell or stress or something like that, which caused me to be a little anxious to change to 100 as I don't want to stress the battery casing or anything.

I have been making this point ... the way you are stating what you read is not quite correct (I do not think the expansion is "visible" to the naked eye), but is heading in the right direction (the effects of expansion / contraction are real and significant if repeated excessively on the margins).

 

[Owner4523]

I have been making this point ... the way you are stating what you read is not quite correct (I do not think the expansion is "visible" to the naked eye), but is heading in the right direction (the effects of expansion / contraction are real and significant if repeated excessively on the margins).

View attachment 1022666

@AAKEE - thoughts on this?

 

[J-a-x]

Thank you for all of this great info. I read somewhere that when you change to 100% you can physically see the battery swell or stress or something like that, which caused me to be a little anxious to change to 100 as I don't want to stress the battery casing or anything.

I've charged to 100% 11 times in my first year of ownership. The trick is I never let it sit too long at 100%. Usually I'll either top it off before a big trip or else if I'm doing something while its on the charger (eating while supercharging on a roadtrip for example) I might let it get to 100% if I'm leaving immediately after.

My car has lately been constantly reporting my range around 320 miles which is what the current EPA range is for my MYLR so the battery is fine so far.

I try to let it sit around 50% when I'm not using it for long periods of time but don't have a 100% record on that. Just trying to keep it around there.

I'd love to see that calendar aging chart with more temperature points. For example at around 5 C is it going to degrade less at say 80% charge than at 25C?

 

[Owner4523]

I've charged to 100% 11 times in my first year of ownership. The trick is I never let it sit too long at 100%. Usually I'll either top it off before a big trip or else if I'm doing something while its on the charger (eating while supercharging on a roadtrip for example) I might let it get to 100% if I'm leaving immediately after.

My car has lately been constantly reporting my range around 320 miles which is what the current EPA range is for my MYLR so the battery is fine so far.

I try to let it sit around 50% when I'm not using it for long periods of time but don't have a 100% record on that. Just trying to keep it around there.

I'd love to see that calendar aging chart with more temperature points. For example at around 5 C is it going to degrade less at say 80% charge than at 25C?

Thanks. I saw someone on one of these threads share a screen shot from a YouTuber video on batteries that alluded to some concern of charging to 100% as it physically stressed the batteries, caused some sort of cracking. Have you heard of this? That sort of gives me pause charging to 100.

 

[Owner4523]

I have been making this point ... the way you are stating what you read is not quite correct (I do not think the expansion is "visible" to the naked eye), but is heading in the right direction (the effects of expansion / contraction are real and significant if repeated excessively on the margins).

View attachment 1022666

I'm curious what @AAKEE thinks about this. If there is really micro cracking happening at 100% of charging, I don't want to do that.

 

[AAKEE]

I'm curious what @AAKEE thinks about this. If there is really micro cracking happening at 100% of charging, I don't want to do that.

I think there is a misstake to talk about what the researchers see in microscopes and discuss things on their level. I have seen example here before when we discussed the ”damage” caused at 100% and some people did read some reports and the words was not interpreted even close to how the authors ment.

We can not see our 2170 or 4680 swelling. Not possible.

I have seen lithium polymer Pouch cells swell from the gases released at high C-rate discharge. This was all cheaper cells, and the high quality cells of the same type has never swollen so I could see this.

My tip is to disregard the microcracking theories and focus on what happening from our perspective. We will never know if we did get microcracks, we only see the capacity degradation mostly.
The ones here afraid of microcracking probably do not even know what this means to us and our car…?

At normal temperatures, 100% overnight is not that bad, it just doubles the degradation rate. Like one night degrading like two nights.
I guess most people know that high SOC is not optimal so we do not need to talk about not to leave the car at 100% for very long periods…
The combination of 100% and high ambient temps is not the best, so if we can avoid long times at 100% during hot periods. This serms extra valid for NMC, where NCA is not as sensitive to heat.

 

[Owner4523]

I think there is a misstake to talk about what the researchers see in microscopes and discuss things on their level. I have seen example here before when we discussed the ”damage” caused at 100% and some people did read some reports and the words was not interpreted even close to how the authors ment.

We can not see our 2170 or 4680 swelling. Not possible.

I have seen lithium polymer Pouch cells swell from the gases released at high C-rate discharge. This was all cheaper cells, and the high quality cells of the same type has never swollen so I could see this.

My tip is to disregard the microcracking theories and focus on what happening from our perspective. We will never know if we did get microcracks, we only see the capacity degradation mostly.
The ones here afraid of microcracking probably do not even know what this means to us and our car…?

At normal temperatures, 100% overnight is not that bad, it just doubles the degradation rate. Like one night degrading like two nights.
I guess most people know that high SOC is not optimal so we do not need to talk about not to leave the car at 100% for very long periods…
The combination of 100% and high ambient temps is not the best, so if we can avoid long times at 100% during hot periods. This serms extra valid for NMC, where NCA is not as sensitive to heat.

Thanks! What I hear you saying is, charging to 100% is fine if you need it and are going to use it right away. Also, any sort of 'micro cracking' that may/may not happen wouldn't even cause any sort of noticeable issue for us in regards to driving our Tesla. I think I also hear you saying there is no need to charge to 100% to 'balance your cells / battery.'

For me, running mock trips through the app. / on board computer, there isn't really a huge difference if I charge to 90 or 100% before a road trip. It may only save me a few minutes at the first super charger. My guess would be 2 extra minutes at the Super Charger is probably 'better' than 100% charging. So I may likely not ever charge to 100% if I don't need to.

 

[jefferrrson]

- Do not charge more than you need* until the next charge. (Reduces the average state of charge)
- Charge often. (Reduces the needed level per above, and the cycle size).
- Charge late, so the car is ready shortly before the drive. In many cases, ready in the morning instead of starting the charge at arrival at home before dinner.
This reduces the average SOC and by that the calendar aging.

For cars with NCA chemistry, 55% displayed SOC or below is good.
For NMC, 60% or below.
For LFP, 70% or below.
(Could be slight differences within the same chemistry, but as a good base these will work).

*)The lithium batteries are not hurt by low SOC. Thats a myth. So, the lower limit should be your own reference for not getting range anxiety, and maybe safety precautions if very cold in the winter.
The battery is happy down to 0%, if you are.

( I do actually not think I wrote what not to do. I think I wrote what parts was not correct, with corrections and also examples from research)

how do i know what type of battery my 2024 Model Y Long Range is?

 

[AAKEE]

how do i know what type of battery my 2024 Model Y Long Range is?

It has been the Panasonic 82.1 kWh before but the recent 2024 EPA test showed only 78.8-78.9 kWh was delivered from the pack (both LR and P).
This indicate a change, as the Panasonic pack always delivered 80.7-82.1 kWh before.
It is possible (logical) that they changed to the LG NMC/NMCA packs with 78.8-79kWh capacity in the Y as well, for the same reason as in the 3.

It need to be checked, preferably by looking on the battery label (info somewhere on TMC where to look, on 3 it can be seen by looking into the center of the car via the wheel well).

From a “preserving the battery” perspective its not a big issue:
Panasonic NCA is happiest below 55% displayed SOC and (LG) NMC below 60% so if you set 50 or 55% your safe.

I use 55% for the daily (model S, and model 3 before) as there is not really a difference between 50 and 55%, so 55% gives the max range at the same degradation.

Set it to 50-55% until you know. If you find out its the LG you can use 60% or below.

@ucmndd: Ping! this thread also covers the batt type, you might have more info on this?

 

[KenBlub]

I am going to predict it is the LG battery. Isn’t the long range model Y no longer eligible for a tax credit in the United States. The tax credit is available if the Panasonic battery is used because the Panasonic is manufactured in the United States.

 

[E90alex]

I am going to predict it is the LG battery. Isn’t the long range model Y no longer eligible for a tax credit in the United States. The tax credit is available if the Panasonic battery is used because the Panasonic is manufactured in the United States.

All US market Model Y still eligible for tax credit. Model 3 lost the tax credit.

 

[AlanSubie4Life]

All US market Model Y still eligible for tax credit. Model 3 lost the tax credit.

Yes, this EPA document is odd. Lookup website is down at the moment so cannot look at the document myself, though I trust @AAKEE is correct.

Will need to keep an eye on this to see what happened. Maybe they decided to go back to the regular 2170s (rather than 2170L) for the faster charging!

 

[AAKEE]

Yes, this EPA document is odd. Lookup website is down at the moment so cannot look at the document myself, though I trust @AAKEE is correct.

Will need to keep an eye on this to see what happened. Maybe they decided to go back to the regular 2170s (rather than 2170L) for the faster charging!

It’s similar capacity to the US M3LR.

 

[AlanSubie4Life]

It’s similar capacity to the US M3LR.
View attachment 1032620

Yeah the M3 LR is expected. But the Model Y is surprising since it gets the POS credit. I told my dad he was getting a Panasonic with his 2024 Y LR. Guess I was wrong? His energy screen method gives 79.5kWh, for what it is worth (probably the threshold). And he got similar numbers on three 2024s on the lot.
Anyway this is high enough it is not likely to be LG or old 2170.