90% the new recommended SOC?

[skhenry81]

I picked up my Model 3 LR RWD from Tesla Oakville this past Tuesday and during orientation they told me day to day should be 80% with 90% if you are going on a road trip. I’m so confused...

I'd go 90% in our climate.

 

[SpudLime]

I’m confused also.
Since taking delivery of my Model 3 in Sep. I have been charging to 80% then driving until battery is down to about 30%, this sometimes taking a week or a few days. What if I only drive a few miles in a day, not uncommon, should I always have the car plugged in, charging from like 70% to 80%?

You should be plugging in every day.

 

[omgwtfbyobbq]

Tesloop found that their Model S battery degradation over the course of the first 194,000 miles was ~6% with multiple supercharges a day to 95-100%, instead of the recommended 90-95%. Between 194,000 and 324,000 miles Tesloop experienced battery degradation of ~22%, but those are extreme conditions
Tesloop’s Tesla Model S Surpasses 400,000 miles (643,737 kM)

Some research has shown < 10% battery degradation after 160,000 miles, and from what I understand 10% is a majority of the degradation that would occur, with the rest happening much slower. It’s going to be much, much better than your typical Leaf that doesn’t have thermal management or whatever. It might be even better for the Model 3 than the Mode S. Don’t quote me on that lol.

For my personal data points: I charge to just under 80% and it finishes around 244-247 miles which sounds just about right. I’ve never charged to 100%. I rent and can’t install level 2 charging so my car is plugged in and charging for about 10 hours which covers my commute, but if I drive more, the car is sometimes charging for a few days straight until it eventually catches up, or I top off at a Supercharger. Car has 17,000 miles on it since July. I routinely drive down to 20-30 miles on long distance trips.

My personal advice is to just keep it plugged in when you have the chance to, charge to what feels right and just let the car manage the battery. Keep an idea of what your typical charge is and if something seems off ask. Apparently for the battery warranty to apply there’s got to be under 70% retention of battery capacity but based on the data no car will get to that point unless something was really wrong
Vehicle Warranty

I personally think climate, overly excessive Supercharging, and maybe constant +90% charge affects battery longetivity the most.

TLDR DO WHAT FEELS RIGHT!

Battery capacity fade will hopefully be minimal after 10%, but it can accelerate in certain conditions (page 9 of this pdf).

https://www.nrel.gov/docs/fy14osti/61037.pdf

That won't matter for 5 years, but it could for 30 years.

 

[jasdelta]

Yes. I often get flamed for asking this, but have you RTFM? Especially the battery section which addresses your question IN UPPER CASE LIKE THIS so Tesla must think it’s important?

Thanks, so After reading it looks like a happy battery is one that is at 90% SOC the majority of the time. I will stay plugged in from now on, but I wonder how many new owners do.
Having never owned an EV and only had this one for 3 months I am pretty new at this.

 

[roblab]

As someone who has a couple 35+ year old vehicles, I'm interested in battery pack lifespan over a lot more than 5 years.

Me too! I'd bet those 35+ year old vehicles don't have any large number of lithium ion batteries with any of the 26 or so chemistries available, and I'd bet you've changed the old PbA battery in them many times. 90% for lithium ion is standard. There is no need to do any less. The batteries are guaranteed for 8 years, meaning they will most likely last twice that. For all you know, any less will shorten battery life. These aren't lead acid.

 

[Eno Deb]

The batteries are guaranteed for 8 years, meaning they will most likely last twice that.

The warranty only covers a 70% capacity retention. Unless you're OK with losing around 100 out of the 310 miles of range I wouldn't necessarily rely on that.

 

[SemiS3XYR]

I’m going to throw wrench in here because its the internet haha...
The more cycles a battery experiences the shorter the battery life.

I support the previous suggestion of changing it up depending on weather, season, and trip specifics. Confuse the hell out of the computer like this topic confuses us. Don’t flame me either but I find that channel annoying because it’s quite superficial.

FTR I’ve never left my electric cars plugged in even if I am gone for a couple weeks. I only top off the Teslas to 70-90 to right before I leave the house by using app or setting a timer. Higher battery SOC only sits a little bit and I naturally start with a warm battery which is good for general performance and great cold weather performance. If I am away on a trip I just charge to 80 and unplug. OTOH In regards to safety something doesnt sit well with leaving all that power plugged into my house if it is not being used. Not everyone can leave their cars plugged in daily or charge daily so they shouldnt sell those users electric cars then if that is the case.

 

[brianman]

90% has ALWAYS been acceptable. The early Model S firmware had two charge settings— daily (92%) and trip (100%). It wasn’t until Tesla introduced the slider to get around stupid EPA rules about averaging two mileage ratings (search if you want details) that if was even possible to set a lower charge limit. All the talk about 70% or 80% being “better” means statistically significant difference in degradation in the laboratory, but it’s never been shown to have a meaningful difference over the time that someone usually drives a car. You can find numerous posts here from Model S owners ( including myself) who continued to charge to 90% every night for five years with no ill effect.

Another data point:
6+ years with the default (Standard then Full) on Sig P85. 226 rated miles at 90%. Never charged above 90%. At least 50 supercharges. 47k miles.

 

[woodisgood]

We've been doing 30 to 80% every weeknight with charging on a 30A circuit (24A actual), car charges to 247 or 248. Now have 10K miles/4 months, so very similar to Kim's car in the video. Will try charging to 100% for the first time this weekend and see what we can get to.

I suspect, and this is kind of reading between the lines because I don't think she explicitly stated this unless it's in the comments somewhere, part of the issue in the video above was not just that they were charging to 70%, but also that the discharges were shallow. In other words, if every time you charge you're going from 60 to 70% or 50 to 70%, it's a lot more confusing for the car's interpretation of its battery capacity than if you're going from, say, 30 to 70%.

Just to update, car charged to 279 at 90% and 302 at 100%, for a degradation of 2.5%.

Then it jumped to 307 a few hours later after it had stopped charging (according to app notification) but was still plugged in.

 

[tread]

What this video and the ensuing dialog illustrate is that (1) Tesla is nearly silent on best practices in their actual instructions to owners, namely the owners' manuals, and (2) there are many opinions expressed here and in other forums by people who seem to think they know the right way to care for the battery, and may or may not have the expertise to give advice to the rest of us. So I for one have always been confused by all the confusing information. The whole discussion of "re-balancing" is a good example. I have always been skeptical of the need for it, because Tesla does not even mention the term in the manuals. Now Kim's video quotes Tesla people talking about guidance for re-balancing, so is it really a "thing?" Do we do it? What is really Tesla's guidance. As in, what guidance would they put in writing and stand behind? It's one thing to put something in a tweet or in a conversation with an individual owner, but quite another to state it unambiguously in a written form for everyone to read, not just whoever happens to be on a particular social media site at a particular moment.

This pretty much sums up why I even posted the video. I've done plenty of reading on best charging practices, and long before I received my vehicle was using the 30 - 80% as my gold standard. I know there are going to be marginal improvements from 80% - 90% limit charging, but it's all very confusing when Elon posts separate numbers himself. He seems like a person that makes definitive statements, so when it shifts from 80% then back up to 90%, I just want a clear reason why.

Yes, I know that he has mentioned that 90% isn't going to harm the batteries that much, and that he's also said that 30% - 80% is the best if you want to eek as much longevity out of the battery as possible, even saying that 70% is what is recommended for users that want the least degradation as possible, etc...

But, when most people talk about how advanced the BMS is, and then I see what is happening to Like Tesla and several users that have similar charging practices, it makes me antsy. I know they're not actually losing any mileage, it's just the BMS being confused, but it's still troublesome to see it happen when those very same charging practices have been okay'ed. Makes me lose confidence even though the battery chemistry is technically not being affected.

 

[Big Dog]

I guess you didn't watch the video?

Actually I did, a couple of times. And it really helps to listen and read with critical analysis skills. What do folks really say and importantly, what are they not saying?

While Kim's thesis maybe correct, there is ZERO corroborating evidence (except her word). Elon's tweet at the 4:48 mark neither confirms nor denies her pov. "Going to 90% is fine" is not the same as 'charging to 90% is recommended.' Not sure why that is so difficult to understand?

Just bcos she says that someone at the Service Center told her x, y, and z doesn't make it official policy, nor does it make it necessarily correct. (I bet we could survey a dozen SC's and get a dozen different answers. I know I did at my SC recently. They are always helpful at the SC, but helpful does not mean knowledgeable expert.)

OTOH, Elon's tweet does represent charging policy. And his tweet at 4:48 is clear.

 

[omgwtfbyobbq]

Me too! I'd bet those 35+ year old vehicles don't have any large number of lithium ion batteries with any of the 26 or so chemistries available, and I'd bet you've changed the old PbA battery in them many times. 90% for lithium ion is standard. There is no need to do any less. The batteries are guaranteed for 8 years, meaning they will most likely last twice that. For all you know, any less will shorten battery life. These aren't lead acid.

Not having "X" is no excuse for a major component being less reliable, especially comparing a battery chemistry that's been around for a century to one that's been around for a decade or so.

I also wouldn't bank on 90% being best for lifespan, but you can do whatever you want with your car.

90% the new recommended SOC?

I'm sure everyone can charge/maintain the battery however they want and it'll be fine over it's warrantied lifetime, but that doesn't mean certain things won't reduce it's functional lifetime.

 

[TexasEV]

This dispute over whether to charge routinely to 80 or 90% reminds me of Henry Kissinger’s quote that academic politics are so vicious because the stakes are so small.

The reason for the debate is because the difference in outcome is so small. If there was a big difference, it would have been obvious long before now and most everyone would agree on what’s right.

Do whatever makes you happy. The battery will be fine either way. I’ve been in the 90% camp since 2013 and plan to stay there. Others say they won’t charge above 80% because if they do they might have a few less miles of range when it’s time for their newborn to start driving. We’re not going to convince each other to change.

 

[Ficheh]

I charge to 90%. The reason being is that, that is where it was set when I picked up the car. I figured Tesla would leave it where they felt it was best. I have charged to 100% when I went on a couple of trips to Tahoe (I'm in SF). I found it no problem to get there with traffic or not (with traffic I had 83 miles of range left (207 actual miles), without traffic 61 miles of range left (206 actual miles)). Coming home with traffic I had 128 miles of range left (205 actual miles), without traffic 144 miles of range left (203 actual miles). Luckily in Tahoe there's level 2 chargers available without cost (they charge my M3 @23 miles/hour, just like my home 240 volt outlet (24A). While home I generally only plug in to charge when available range drops to 100 miles or less. Most days, if I'm not using the car, I get a drain of 2-3 miles of range (very rarely I get no loss). My typical daily commute is 32 miles so I don't really worry about not having charged the night before. From what I've read, the biggest contributor of capacity loss is using Superchargers, which I've yet to do (especially since they're going to charge me for it anyway). For those who care, charging @ Tahoe put 61.24 kWh back into my car and took 11:12, coming home I put back in 41kWh. So the massive elevation change (0-7200-5000 ft going up and 5000-7200-0 ft coming home) makes a huge impact on energy consumption (as it should). Coming home, energy consumption was 199wh/mile.

 

[gh0001]

I am confused regarding shallow charging. Some people say shallow charging is good so you should plug it in whenever possible but some say you need deeper charge so not to confuse the system?

 

[BerTX]

I am confused regarding shallow charging. Some people say shallow charging is good so you should plug it in whenever possible but some say you need deeper charge so not to confuse the system?

You can find anybody who says anything. Welcome to the Internet.

I would say shallow charging is best, with occasional deep charging to calibrate the systems.

 

[Knightshade]

I am confused regarding shallow charging. Some people say shallow charging is good so you should plug it in whenever possible but some say you need deeper charge so not to confuse the system?

Owners manual says leave plugged in as much as possible, FWIW

 

[TexasEV]

I am confused regarding shallow charging. Some people say shallow charging is good so you should plug it in whenever possible but some say you need deeper charge so not to confuse the system?

Who cares what some people say? Have you RTFM? Especially the battery section which answers your question IN UPPER CASE LIKE THIS so they must think it’s important?

 

[Big Dog]

This pretty much sums up why I even posted the video. I've done plenty of reading on best charging practices, and long before I received my vehicle was using the 30 - 80% as my gold standard. I know there are going to be marginal improvements from 80% - 90% limit charging, but it's all very confusing when Elon posts separate numbers himself. He seems like a person that makes definitive statements, so when it shifts from 80% then back up to 90%, I just want a clear reason why.

Yes, I know that he has mentioned that 90% isn't going to harm the batteries that much, and that he's also said that 30% - 80% is the best

Your title is misleading. There is no change to "recommended" (yet), as your research shows. Just bcos Kim opines it and Kim has a blog, does not make it so.

 

[TT97]

Who cares what some people say? Have you RTFM? Especially the battery section which answers your question IN UPPER CASE LIKE THIS so they must think it’s important?

Well, they either think it is important or they are trying to reduce their liability. Telling people to plug in reduces the likelihood that someone messes up and runs out of electrons but is not necessarily the best solution for long term battery health.