That's an invalid comparison - I have trips that one way consume over 350 Wh/m, and on the way back around 210 Wh/m.
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Maximum charge level for daily use
- Thread starter dhoonlee
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If you reread the post the round trip (with Aero wheel covers) was 284 and 249 for an average of 266.5Wh/mi. For the same trip (without Aero wheel covers) the energy consumption was 304 and 278 for an average of 291Wh/mi. The Model Y used an additional 9.19% Wh/mi without the Aero wheel covers. If the test was performed on different days conditions, i.e. prevailing winds or wet versus dry roads could have been a factor.
The test was performed on a Model Y with the 19" Gemini wheels. The Aero wheel covers for the Model Y only come, fit the 19" Gemini wheels.
Yes, missed that. Still hard to believe the difference is really that much. And indeed would be good to compare 19" (with and without covers) vs. 20" and 21" wheels.
I'm surprised people get surprised by this (grin). Stick your hand out the window at 60 mph and feel the force of the wind. The car is using most of its energy to push the air out of the way, and aerodynamics thus make a huge difference. Look at the car design; smooth, very few shape edges. Even the underside is smooth (one of the places BEVs can do better then ICE). So those wheels stirring up the air and creating lots of nasty eddy swirls can REALLY mess with the sleek airflow.
Constantly using the higher state of charge causes more damage. That eventually leads to the battery not being able to hold as much energy. It's not more complicated than that.
And if you don't need all that extra range every day, you can avoid that battery damage at no inconvenience.
HenryT
Active Member
My point was simply that in the ranges I quoted the effect even long term will be minimal.
I accept that using a battery means it will ultimately diminish in its effectiveness, but again, my point is that the value achieved by limiting the charge from 90% to say 70% will be miniscule.
HenryT
Active Member
I think you misunderstand my position - I don't doubt higher charge limits have an effect, (that said, presumably an increased number of charging cycles has an effect too?) but my question is simply about the significance of the gain/loss.
In my first post on this topic (#75) I was trying ask what exactly are the consequences, not state that there are none. There is a weight of argument that 'less is better' but in my ignorance I have been trying to establish by how much?
Again, my question of the extent of gain/loss is also raised in my second post #80.
This thread: Is it ok to charge Tesla Model 3 only once or twice a week? has a lot of useful discussion of different charge methodologies. Be careful of the chart though, and see my post later in the thread about correct interpretation. Basically it shows that a 75/25 model does extend the battery life compared to a deeper charge cycle. The difference is not dramatic, but not negligible either. I think the basic take-away is that, all other things being equal, you are better charging to 70-80%, but should not be worried about using deeper charges when necessary.
And there has been a lot of research done on the physical degradation of the battery structure and how that correlates to deeper charge cycles (my apologies I cannot find the references to those right now).
My feeling overall is that its prudent to be gentle on the battery, it does it no harm, and it may do it some good, but not to fret over deeper cycles once in a while. Which is pretty much the same way you treat an ICE car really
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Yes, from what I’ve read, it is best to keep the average at 50% state of charge. However, this is diminishing returns, so the effect of keeping it at 60 or 70% state of charge is less significant compared to someone that keeps at at 90 or 100% state of charge.
if you were someone that uses 20% state of charge per day, ideally, you would want to charge to 60% and when you arrive home you are now at 40%. The median here his 50%. However you may want extra power just in case you decide to be spontaneous or whatever, so 70% may make more sense.
worst case scenario if you were out, you would just have to find a Supercharger somewhere. I wouldn’t let the minutiae of battery management stop you from enjoying your car.
if you were someone that uses 20% state of charge per day, ideally, you would want to charge to 60% and when you arrive home you are now at 40%. The median here his 50%. However you may want extra power just in case you decide to be spontaneous or whatever, so 70% may make more sense.
worst case scenario if you were out, you would just have to find a Supercharger somewhere. I wouldn’t let the minutiae of battery management stop you from enjoying your car.
Keep in mind that velocity squared component of drag. At 65 MPH, the top of the areo cap is moving forward around 88 MPH, the vertical moving components at the front and back edge are moving around 44 MPH, and the bottom is going 0. It's easier to understand using Calculus, but this is an easy way to visualize the concept. Given the complex fluid dynamics of this system, it is hard to accurately predict the real world drag difference the caps make.
The top of the wheel is going 130, and the top of the areo cap is going about 19/28th of that speed. The spokes don't quite go that fast at the tips since they are a little bit smaller than the 19" wheel, but they are certainly going faster than the ground speed.
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