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90% the new recommended SOC?
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They didn’t forget it, they never knew it. It’s not like when we ordered the Model S and we read most of the posts here. Don’t you know that for most Model 3 owners history begins on the day they get their car? I’ve posted about this and the crazy EPA rule that prompted Tesla to introduce the slider in a firmware update several times in recent months but no one seems to read posts that are dated before their Model 3 ownership.
saltsman
Member
Eno Deb
Active Member
Back in the day, we had to drive 150 miles to the next Supercharger! In the snow storm! Uphill ... both ways! Now get off my lawn.
Seriously, when Tesla introduced the charge limit slider that was probably in part because of what the EPA did to the Nissan Leaf, although that was never confirmed. But that wasn't necessarily the only reason. We have Tesla battery researchers and Musk himself recommending charge limits of 70-80% for daily use. Couldn't be any clearer?
Atari2600
Active Member
Charge to 70 to 80% of the battery or 70 to 80% on the sliding scale in our Tesla cars? I don't think those are the same thing.
Eno Deb
Active Member
As far as we know the buffer between total and usable capacity is only a few percent on Teslas (with the exception of the software-limited Model S 60), so it doesn't really matter.
voip-ninja
Give me some sugar baby
So I’ve always followed the TMC folklore advice and kept my car charged to 70-80% since I got it three months ago.
After reading this new info I have been charging to 90% the last two weeks but I don’t charge daily as I get free charging at my work and it’s difficult to charge every day.
I did my first charge to 100% the other night before driving 100 miles round trip.
The car only showed 304 miles in a full charge.
Has my car lost 2% range in 2,000 miles of ownership or is this a residual effect of me not regularly charging the car to 90%
?
After reading this new info I have been charging to 90% the last two weeks but I don’t charge daily as I get free charging at my work and it’s difficult to charge every day.
I did my first charge to 100% the other night before driving 100 miles round trip.
The car only showed 304 miles in a full charge.
Has my car lost 2% range in 2,000 miles of ownership or is this a residual effect of me not regularly charging the car to 90%
?
Eno Deb
Active Member
It's most likely just a small estimation error. If it bothers you try discharging the battery to <20% so the car can calibrate the estimator on both the higher and lower voltages. But I don't think this small error is worth it.
Atari2600
Active Member
If 4.1v is the optimum voltage, as stated earlier, there should be an option to charge to that.
I just did my first 100% charge on my Model 3 performance (that has 240 miles on it), just to see if it would charge to 310 at 100%. It charged to 306. This is on my recently installed Tesla Wall connector, 60amp circuit charging at 48amp.
There a bunch of different Lithium Ion chemistries though all used for different purposes. If your car's battery was made up of the same thing as in your cell phone, you would not get the same performance or longevity.
I've got about 8,500 on my M3 RWD. I was regularly charging to mostly around 70% at first, and within the first 4,500 miles or so, my extrapolated full-charge rated range dipped all the way down to 285 miles. Then, after looking at these forums, I started charging to 90%. Within a week, my rated range, 100% full charge, went back up to 300 - 307. Now, I charge to 80% for a while, and the range invariably drops down to just under, 300 at full charge (extrapolated), then I charge to 90% for a week or two, and my range pops right back up to 310.
It is my personal experience that the BMS is not good at giving you an accurate rendition of your estimated full 100% rated range when you regularly charge to 70-ish% and you maybe use 10,15% of that on a daily basis (like me).
There is a firm conviction in these forums that charging to 90% doesn't appreciably affect your long-term degradation rate adversely, as it has not seemed to do with the S/X cars. Model 3's have slightly different batteries than the S/X's so it's not clear if the same dynamics will or will not hold here. But one thing is clear: Charge to 90% regularly, and your rated range at 100% SOC will increase back to or back close to 310 (for a RWD LR model at least).
This is good data, but keep in mind that the measurement is just OFF. There is no guarantee that re-calibrating will bring it UP every time. It often goes down, too.
This is good data, but keep in mind that the measurement is just OFF. There is no guarantee that re-calibrating will bring it UP every time. It often goes down, too.
I haven't experienced it going down when charging to 90%. It does go down when I start a regime of 70-ish% SOC though. Honestly, I haven't heard of it going down when one charges consistently at 90%, only up. But I'm sure there's somebody out there who has.
I do appreciate that all one is doing is re-calibrating the BMS's estimate, and not literally the battery (though there does seem to be some "rebalancing" of the charges of the cells/packs that happens when one charges to higher percentage SOC). There is some info out there that suggests that if your BMS's "estimate" starts to turn downward like mine did, the BMS actually will limit charge to that lower extrapolated 100% SOC range, but I don't know how true that is. (E.G., by charging to 70% over time, one's estimated 100% SOC rated range might show, as mine did, 287 miles. The idea is that, if this is what the BMS thinks, then indeed that's the range (rated) you'll be getting - it's reading the cells inaccurately, in other words. Don't know if that really is happening, but I've seen on the forums some discussion about that)
halfricanguy
Model 3 - LR RWD - MSM
Just continuing to add my data, after charging to just under the 80% line for about 5 months, I charged to 100% for the first time for a trip (via standard 120 volt outlet). I can’t wait for it to finish completely, but it looks like it’ll come to exactly 310 miles.
Update - it finished right at 309. Somewhat related question- does anyone know if slower charging speed equates to more time for the battery to rebalance or whatever, and display a more accurate SOC?
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Doesn't matter on the S and X. Balancing starts when the pack hits 93% and continues until done, regardless of pack state of charge or if the car is plugged in or not. Essentially, the BMS top balances the pack by calculating how much power needs to be drained from each group of cells, and goes until it has drained the requisite amount from each. It doesn't matter if charging stops during the process, or if you drive 100 miles while the balancing is happening.
I don't see why they'd change it for the 3.
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