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Model 3 Performance Battery Degradation One Month (Story)
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The following is what I posted originally from my discussion with the tech:
Talked to Tesla software tech at the Gigafactory for about a half hour today and feel very good now about what I learned. After hearing about my charging patterns, logged battery levels, and driving experiences plus my time owning a Leaf and a Prius, he had me try some recommendations that others here may want to try. First he said that my short daily drives of 5-40 miles and then charging back to 70% can stop. He recommends only plugging in when I get down to maybe 100 miles range before charging back to 70-80%. Next he recommends running the car down to about 10 miles of range and charging back to 100% once a month. He wants me to take the car off a scheduled start time as it will prevent the car from using line power after reaching the set charge limit until the next charge time. That would explain why my range dropped while still plugged in. He said theymay address that in an OTA update in the future. We talked about several reasons foe these recommendations but most of my own problem sound self induced without meaning to.
So not quite a week and my results are great. Could be unrelated but that advice is what I started following and in my own use patterns, it is working for me.
Supercharged twice this weekend after a long road trip and hard driving over back roads. Went from 80-247 Miles the first time, stopped itself at 80% The second time went from about 120-230 before I stopped as I didn't need more for the rest of the weekend No other charging since friday at work when i did a 90% charge for 278 Miles before leaving, since I knew I was going to drive a lot.
Charged today at work again, to 80% and got 248 miles when it stopped itself. 1031 miles on the car, 4 supercharges in now and happy to see such a strong pack.
I do not plug in at home at all, only work. My commute is about 80 miles round trip so I charge each day at work and supercharge on the weekends.
Charged today at work again, to 80% and got 248 miles when it stopped itself. 1031 miles on the car, 4 supercharges in now and happy to see such a strong pack.
I do not plug in at home at all, only work. My commute is about 80 miles round trip so I charge each day at work and supercharge on the weekends.
Y'know, as a Model S owner since 2012, now with 2 model 3s as well... 310 miles range is such a luxury, I just don't sweat anymore. I don't always plug it in every night. When I go out of town, I set it down to 60%, and sometimes don't remember to set it back for weeks. Because, for many people (including me) getting up with 200 miles is plenty. A 3 at 65% is the same as my P85 at 80%. Just much less need to be anal. When I KNOW that I'm going somewhere that requires range, I just pump it up to 80, 90 or 100% as required. Even for long drives, I often don't start with 100%... I'd much rather arrive at first Supercharger near 10% so it charges faster.
I didn't start questioning my range until closer to 2000 miles and then it was more of asking why range was dropping while still plugged in and not driving the car. Tesla tech told me to start a log and report back. After that was when I started seeing the extrapolated numbers drop to less than desired. My 70% charge was down to 196 miles so I was getting concerned. After following the advice of the tech, my reported range is back up. He said it was to do with my such limited use of the car and such shallow daily charges so I quit charging that way and it seems to be working for me.
While I appreciate the "Unknown Tech" input I really would feel a lot better following advice that percolated out of official channels.
Is this truly a case where the manual is "Less Right" than the physics? This could be a case where the manual instructions are better for Tesla than the consumer.
For instance, an easy solution like "always plug in" might give 95% of the good effect that tesla wants, but the 5% (maybe charging longer than strictly needed) is better than the alternative of dealing with several thousand confused customers who aren't looking to tweak things, just looking for an easy rule to follow.
For the other people who really want to discuss 0.5C vs 1C vs 2C charge rates and the various degradation, and benefits from occasional deep discharges and 100% recharges, it would be nice if there were advanced instructions that were official.
FWIW, I also did a deep discharge (56 miles available) and 100% range charge during my first 2 weeks of ownership. I got 309 Miles from my first 100% charge.
That makes no sense. If you arrive with a higher state of charge, it will always take less time to get to the charge you need than if you arrive with a lower state of charge. When you arrive at 10% SOC, sure you start off charging faster than you would at 50%, but your total charge time will be longer.
Think of it this way-- if you plan to depart the supercharger with 250 miles range, for example, would your charging stop be faster if you arrived with 30 miles range or 100 miles range?
Your first supercharging stop will always be faster if you start from home with 100% charge.
You may be confusing higher accuracy of what the battery management system reports with actual improvement in the battery.
Not sure what you're saying here. I was just adding a data point, which may reinforce what JeffnReno reported, that deep discharges and charges keep the rated range either accurate, or looking accurate.
Whatever the reason or reasons my battery seems happy. Whether that is luck in getting a strong pack, by taking care to zero the algorithm by deep charging and discharging I don't know. I certainly am not following the manual though as I don't "Always Plug in".
Impossible to tell in just a few weeks what is best long term from the data we have.
I for one appreciate the additional input. I think we’re all just trying to uncover the truth. If the tech is correct then the manual seems wrong and Tesla should update. It also seems possible that the tech’s advice applies in a certain context but not generally. Thanks for posting your experience.
For the first couple months and 2k miles all was exactly 310 extrapolated and twice charged to 100% and was 310 displayed, then things started changing so I started questioning. Coming from a 2012 Leaf that had lost 3 capacity bars, I am probably more anal than I need to be.
I think if I was going to obsess about something, the Battery capacity is appropriate. Not only the most expensive replacement component but also the component we have the greatest control over its long term health by our daily schedules. We also get an extremely accurate capacity bar, so the tendency is to pay attention to it. Imagine if we only got our capacity bar in increments of 5 or 10 miles!
No, that's not what I meant.
I charge mine exactly as you say is the best: daily to 70-80%. And currently I've got an observed/displayed range decrease of slightly over 7% at 6,000 miles, 4.5 months out - which is a concern, especially if you're telling me (as I've seen on the Net as well) that 10's of 1000's of other Tesla owners have only a 5% range loss after 5 years, and yet I'm already exceeding that degradation in less than 5 months, following the exact same charging strategy as that vast population.
My comment was directed at what I believe is slightly ambiguous language of the manual, which recommends keeping the car "plugged in" every day but isn't clear to me whether that means it would be charging every day. I was thinking it would be clearer if the manual specifically addressed whether charging daily or not is a good/bad/no change idea (because there are circumstances where the car could be "plugged in" but not charging.)
1. You probably haven’t lost range, you’ve probably lost accuracy of the estimated range that’s reported. Try charging to 90% routinely, not 70-80%, and over time I expect your reported range will increase.
2. The manual does address what you ask. “There is no advantage to waiting until the battery level is low before charging. In fact, the battery performs best when charged regularly.”
Eno Deb
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Personally I'm more interested in the real capacity than the reported one.
All research I have seen indicates that lower peak charge voltages increase the longevity of the battery, see e.g.:https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
"Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles."
So it's better to cycle, say, between 50 and 70% than between 70 and 90%. On the Model 3 70% is still over 200 miles which is probably more than enough for the daily use of the vast majority of people.
Yep. Here's another quote from the source above:
"Cycling in mid-state-of-charge would have best longevity."
1. I hope you're right. I have an appointment with the Dublin SC about the apparent battery degradation, based on displayed range. My hope is that the answer is that there is no degradation, or much less, and indeed it's some sort of calibration thing. I might wait until the appointment on Friday before changing my SOC to 90%, and ask the guys there what they think of doing that. Definitely going to address this rebalancing/recalibration thing with them, as I'd much rather all of this be about simply the accuracy of the estimated range.
2. Right, I see what you mean. Thanks for that!
diamond.g
Active Member
85->90 were chemistry changes, 90->100 there are physical changes (or at least I think that is the case).
If I am not mistaken the 90/100 chemistry is the same as the 3's. I don't think that means the BMS is the same though as the modules are layed out differently.
OK, your logic is fine. We are getting into fine points of road trip strategy. What I meant was that if I can start out the day aiming for a supercharger that is 250 miles away, and after that I’ll be stopping at 125 mile intervals, there’s no huge value in starting the day at 310. I want the buffer to be 10% or so and always be working from bottom of the battery after that. You are right, the first SC stop of the day would be marginally shorter.
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