WilliamG
Active Member
Unless you're driving down a huge hill the entire way I simply can't see that possible. You're saying you recouped 5% of your battery? How long is your drive, and how much elevation change is that?
Charging beyond 90% daily
- Thread starter Turlejay
- Start date
Unless you're driving down a huge hill the entire way I simply can't see that possible. You're saying you recouped 5% of your battery? How long is your drive, and how much elevation change is that?
And so therefore a warm battery at departure is more important than the extra 5%
ElectricIAC
Devil’s Advocate
The initial part of my drive is on city streets and with bad regen levels sees around 400wh/mi. With proper regen it’s closer to 250wh/mi.
AlanSubie4Life
Efficiency Obsessed Member
I'd strongly consider verifying this yourself rather than trusting one datapoint on a forum. If you are in a flat area and can avoid the use of the brakes, it is going to be more efficient to drive that way than it would be to drive and rely on regen, as that is not a 100% efficient process. So you should get the best (or equal to other levels best efficiency) efficiency when your battery starts at 100%, as long as you do not use the brake at all. Which is obviously a huge caveat and in many situations may not be possible. The advantage of a 100% full battery is it completely disables regen, which means that as long as you drive in a way as to completely avoid using the brakes, your drive should be as efficient as is possible. Just saying that the hypermiling talents of predicting light changes, and not racing from light to light, and predicting the future speed of traffic, are not pointless, even if you have a car with regen which makes it "not needed." (People who rely on regen to slow down will get worse efficiency than those who coast to a stop.)
Personally, I can't employ this strategy, because San Diego and my commute is simply too hilly to allow it, and I have to be careful not to charge too much at home, as I am at relatively high elevation.
The reason this is relevant to this discussion is that you may well need to charge to 100% next winter, when your car has 50kWh of capacity (228rmi at 100%) rather than its current ~53-54kWh. And you should not fear that somehow charging to 100% is going to automatically lead to worse efficiency - unless you and your wife live on top of a hill or your wife has to deal with a lot of downhills before hitting the freeway, 100% can be ok.
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AlanSubie4Life
Efficiency Obsessed Member
Not sure if you have a 2020 or a 2019 SR+ (it matters).
To get the rated range (to 0%, not including using any of the buffer) in a 2019, you'd like to see around 205Wh/mi on the trip meter.
To get the rated range (to 0%, not including using any of the buffer) in a 2020, you'd like to see around 200Wh/mi on the trip meter.
It will not be possible to achieve anywhere close to this when traveling at 75mph. You'll be closer to 250Wh/mi absolute best case (not this time of year!), which means with no HVAC, you'll have about 195 miles of range real world at those speeds.
To be able to complete the trip of 100 miles round trip, starting at 100%, and ending at 0%, you must see a trip meter average of less than 500Wh/mi. But that does not include any losses at work, so you must be lower than that.
We do have a few hills to climb and go down before the freeway. Once there it's pretty flat. As of right now I'm comfortable with the standard 90% or even the 85 I had been as she's getting better at conserving energy. She was at about 70% efficiency today in 15F weather. The car had a little over 50 miles left on the screen when she got home
AlanSubie4Life
Efficiency Obsessed Member
If you post the round trip data, including: 1) starting rated miles, 2) ending rated miles, 3) round trip "since last charge" stats, and 4) Trip meter stats for the work->home leg, from a trip your wife makes, it could be analyzed. Note the trip meter resets every time you have exited the car and then put the car back in drive. (You can check it after the car has been left sitting, as long as you do not leave Park.)
Extra bonus is for your wife to take a picture of the trip meter when she gets to work along with the rated miles upon arriving at work. Bonus because having your wife take this picture may be more than you want to request of her...don't want to let on that you have concern...
But that would allow easy tracking of typical energy loss at work. You'd have to switch to distance display rather than energy display.
If you post the round trip data, including: 1) starting rated miles, 2) ending rated miles, 3) round trip "since last charge" stats, and 4) Trip meter stats for the work->home leg, from a trip your wife makes, it could be analyzed. Note the trip meter resets every time you have exited the car and then put the car back in drive. (You can check it after the car has been left sitting, as long as you do not leave Park.)
Extra bonus is for your wife to take a picture of the trip meter when she gets to work along with the rated miles upon arriving at work. Bonus because having your wife take this picture may be more than you want to request of her...don't want to let on that you have concern...
You'd have to switch to distance display rather than energy display.
Teslastics does this for me, no? Also, she knows we are experimenting. All is well at casa turtle
AlanSubie4Life
Efficiency Obsessed Member
No idea! It depends on whether they stay on top of the various changes in constants, etc., and how they manage all that data.
AlanSubie4Life
Efficiency Obsessed Member
The rated line has changed position. It sounds like the charging constant is around 213Wh/rmi. That's based on people's reports (pictures of Energy screen). Previously it was 219Wh/rmi.
If you look at my post about 2020, 2019, 2018 Model 3 Battery Capacities & Charging Constants, you'll see that the SR+ for 2020 is a little odd. The test vehicle had very low capacity (only 52.7kWh vs. 54.5kWh for the 2019 test vehicle). So I hand adjusted the energy value in the numerator of the Wh/rmi constant calculation UPWARDS by 0.6kWh for the rated mile constant, to get to the 213Wh/rmi observed value, in that spreadsheet. All the values in orange are direct unmodified from the EPA submission.
But note also the 2020 SR+ is EXTREMELY efficient. About 8% more efficient than the 2019 SR+. Totally unrelated to the capacity... But the constant was only adjusted by 3%.
For this thread, though, this improvement may not be as relevant, as those are drivetrain improvements and the big issue here is HVAC usage (which will not have changed). It's also possible those efficiency improvements have been retroactively applied to the 2019 SR+ (no idea). But that would not change the constant on that 2019 vehicle most likely.
ElectricIAC
Devil’s Advocate
Do you feel this applies also to the SR or will this just be slightly more SW limited to keep in current step?
AlanSubie4Life
Efficiency Obsessed Member
No idea. Also no way to know (no way to measure efficiency without a calibrated dyno). They won't change any constant values on the old SR I don't think. They have not retested the SR for 2020. And I don't know whether they will sell the SR in 2020.
If I get bored this weekend I will crank my heat on for 30 minutes so I can have regen on right away when I leave. I think I would lose 30+ miles of range(10% of the battery). I just find it impossible to believe that I'd make that up with regen on a trip that is less than 200 miles.
It's not 15 cents of shore power to get 30 miles of range.
Right, you’ll never make it up. You won’t make it up on a short or long trip.
AlanSubie4Life
Efficiency Obsessed Member
If you set temp to max and have AC on for 30 minutes, you’ll probably use 12.5kW (maybe only 9kW), based on that other post here. So 4.5-6.25kWh, which is 19-27 rated miles for your LR AWD.
It definitely makes no sense unless you are going to start with 2500 feet of steep downhill. Seems like kind of a corner case! There’s 4kWh of energy to reclaim there so might just start to make sense.
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