Tesla sets charge limit to 90%

[AAKEE]

I have some strong caviats to that article.
I do not have the time to write a large pist at the moment.
But for starters:

• Similarly, precondition the battery before fast charging in extreme cold. Often, driving a bit before fast charging is enough to warm up the battery, or get to the fast charger using your car’s navigation.

For the bold part, no it will not. The battery warms quite slow from normal driving.


(Maybe if you live in a hot climate with the battery already almost warm enough before the drive. But even warm climates isnt warm enough in some parts of the year. But the question was in extreme cold).

• Avoid fast charging your EV at very low states or very high states of charge, since battery resistance will be higher.

There is no reason not to supercharge at low state of charge. The bad thing with supercharging comes from charging cold batteries and high currents at high SOC, if we read the research about fast charging and lithium plating.
The research shows that soft start with a ramp up of the current/power is good. Tesla already does this.

Speaking of lithium plating: Thats the main reason that causes bad things in batteries from fast charging.
Eventually it will cause shorts in the cells and then the battery is done.

Preconditioning will warm the battery ehichbis good.

I think the article sends a message that might not be that good.

 

[Rocky_H]

There is no reason not to supercharge at low state of charge.

I don't believe that's true, and it comes directly from Tesla. Do you remember the "Tesloop" service, where someone was running a car shuttle service from Los Angeles to Las Vegas? They had several cars and ran some of them up to 3 or 4 or 5 hundred thousand miles. Most of those did have to get battery replacements. Some of the articles about this included the quotes from Tesla service about the battery replacements. Tesla even said they were glad to get some of this data from the Tesloop cars because they were finding out a couple of things about extremely high usage on the batteries.

Here’s how a Tesla Model S holds up after 400,000 miles in 3 years - Perriott Partners

Tesla’s vehicles are becoming increasingly popular with taxi and shuttle services, which are pushing their vehicles a lot over short periods of time – giving us a good glimpse at how the cars hold up with high mileage. Tesloop, a Tesla-only shuttle service based in Southern California, recently...

perriottpartners.com

Tesla pointed out a couple of specific things that were causing the most harm to the batteries. Most of it we know, like tons of Supercharging, and frequently going to 100%, but the one that was a bit new to us was immediately Supercharging when the car had just been driven down to a very low state of charge.

"Found internal imbalance in HV battery due to consistent supercharging to 100% from a low state of charge (SOC) without any rest periods in between. "

"We also recommend that the customer use scheduled charging to start charge 3 hours after end of drive at low SOC."

Granted, I'm going to still do it, because that's what you do when traveling, but it was interesting to hear that Tesla recommended that it's healthier for the battery to have some time off when it has just gotten down to low SOC instead of immediate fast charging.

 

[tesluv108]

I have always charger to 90% for the eight years I have owned my model s.

Did your battery ever fail?

 

[tesluv108]

I don't believe that's true, and it comes directly from Tesla. Do you remember the "Tesloop" service, where someone was running a car shuttle service from Los Angeles to Las Vegas? They had several cars and ran some of them up to 3 or 4 or 5 hundred thousand miles. Most of those did have to get battery replacements. Some of the articles about this included the quotes from Tesla service about the battery replacements. Tesla even said they were glad to get some of this data from the Tesloop cars because they were finding out a couple of things about extremely high usage on the batteries.

Here’s how a Tesla Model S holds up after 400,000 miles in 3 years - Perriott Partners

Tesla’s vehicles are becoming increasingly popular with taxi and shuttle services, which are pushing their vehicles a lot over short periods of time – giving us a good glimpse at how the cars hold up with high mileage. Tesloop, a Tesla-only shuttle service based in Southern California, recently...

perriottpartners.com

Tesla pointed out a couple of specific things that were causing the most harm to the batteries. Most of it we know, like tons of Supercharging, and frequently going to 100%, but the one that was a bit new to us was immediately Supercharging when the car had just been driven down to a very low state of charge.

"Found internal imbalance in HV battery due to consistent supercharging to 100% from a low state of charge (SOC) without any rest periods in between. "

"We also recommend that the customer use scheduled charging to start charge 3 hours after end of drive at low SOC."

Granted, I'm going to still do it, because that's what you do when traveling, but it was interesting to hear that Tesla recommended that it's healthier for the battery to have some time off when it has just gotten down to low SOC instead of immediate fast charging.

I’m not trying to be a smartass here so don’t take it that way. What has Tesla said about low mileage failures when adhering to their guidelines? I’m gonna answer that and tell you that they’ve said nothing. They don’t want the negative press. They won’t release detailed failure numbers either. I’m pretty sure they have no idea why certain packs are failing. Also they’ve developed this ultra crappy stance towards individuals that purchased their ultra expensive earlier cars. As many have stated Tesla could easily replace a pack at cost and create a lot of goodwill. This doesn’t appear to be happening ever. What is my point? My point is even if you follow Tesla’s guidelines to the letter you are likely to have a battery fail on you just outside of their warranty window. As Stevie would say, very superstitious.

 

[AAKEE]

I don't believe that's true, and it comes directly from Tesla. Do you remember the "Tesloop" service, where someone was running a car shuttle service from Los Angeles to Las Vegas? They had several cars and ran some of them up to 3 or 4 or 5 hundred thousand miles. Most of those did have to get battery replacements. Some of the articles about this included the quotes from Tesla service about the battery replacements. Tesla even said they were glad to get some of this data from the Tesloop cars because they were finding out a couple of things about extremely high usage on the batteries.

Here’s how a Tesla Model S holds up after 400,000 miles in 3 years - Perriott Partners

Tesla’s vehicles are becoming increasingly popular with taxi and shuttle services, which are pushing their vehicles a lot over short periods of time – giving us a good glimpse at how the cars hold up with high mileage. Tesloop, a Tesla-only shuttle service based in Southern California, recently...

perriottpartners.com

Tesla pointed out a couple of specific things that were causing the most harm to the batteries. Most of it we know, like tons of Supercharging, and frequently going to 100%, but the one that was a bit new to us was immediately Supercharging when the car had just been driven down to a very low state of charge.

"Found internal imbalance in HV battery due to consistent supercharging to 100% from a low state of charge (SOC) without any rest periods in between. "

I guess you read in to much about low SOC (things that wherent written).
No rest period would be the number one cause to imbalance, as the balancing mostly will need to happen at rest.

"We also recommend that the customer use scheduled charging to start charge 3 hours after end of drive at low SOC."

Heres more of the same text:

Also recommend that customer does not Supercharge on a regular basis and does not charge to 100% on a regular basis. We also recommend that the customer use scheduled charging to start charge 3 hours after end of drive at low SOC.

The scheduled charging after three hours most certainly is put there to give the car/battery a three hour rest (as it never did, if we read the above “no resting periods).

Granted, I'm going to still do it, because that's what you do when traveling, but it was interesting to hear that Tesla recommended that it's healthier for the battery to have some time off when it has just gotten down to low SOC instead of immediate fast charging.

There is no support in the research for not going low on SOC.
Most tests is down to the real 0% (2.5V/cell) and most of them show that the real reduction in wear is by cutting the upper part of the cycle.

This is also in perfect line with the Tesla advice about reducing the high part of the high SOC. They did not recommend reducung the low SOC part.
These cars was doing multiple runs each day, so all they asked for was a three hour respit time + do not go 100% or so.

Below, I’ve already posted it perhaps 30 times with full description, I do not onow if I is up to write the description again. It is panasonic 18650 NCA, as close to model S cells as possible. 100/90/80%

Same type of cells, all was discharged to 2.5V (real 0%).
The lower the soc range, downwards the less cyclic aging.

Here we can se that discharging to 0% (2.5V) causes slightly more wear than stopping at 3.2V (about 10%), on the other hand it is a larger cycle (the comparable started at the same SOC so all the stop at 3.2V is expected to wear less, as smaller cycles do.

 

[Rocky_H]

I guess you read in to much about low SOC (things that wherent written).

Nope.

No rest period would be the number one cause to imbalance, as the balancing mostly will need to happen at rest.

Yes, that's the part I copied and pasted.

The scheduled charging after three hours most certainly is put there to give the car/battery a three hour rest (as it never did, if we read the above “no resting periods).

Yep, that is the part I posted.

There is no support in the research for not going low on SOC.

I didn't claim that it did, and therefore didn't need this last half of your post that you've done plenty of times.

This thing was specifically about immediate recharge when it had just gotten low. That's it. And Tesla said about this that they discovered they didn't have it accounted for in their firmware with really high usage batteries that had been repeatedly experiencing this, that they would get into this weird behavior of shutting off with significant energy still left.