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Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health
- Thread starter KK_RedM3
- Start date
AlanSubie4Life
Efficiency Obsessed Member
And tires - and alignment! EVs are sensitive to tires and alignment - put the wrong tires on the car and efficiency will take a big hit 10-15% is not unusual!
FWIW my '18 Model 3 is about the same in the same climate.
Smaller wheels are great for extending range!
My experience with the Crossclimate 2s is that you will get a significant hit in range at highway speeds - about 10% and it gets worse the faster you go. They tread pattern is pretty knobby and I suspect they have high wind resistance more than high rolling resistance.
They do work great in the rain and snow, though, but honestly I can't recommend them if you want to avoid a big range hit. I do need to double check alignment, though to make sure they are in spec.
Thats right, increased range means the BMS thinks the capacity is higher. The real range will not increase as the battery capacity in real life only goes one way = down.
AlanSubie4Life
Efficiency Obsessed Member
While true in general under standardized conditions, can’t you extract more energy from a battery at warmer temps? (This is a question, not rhetorical.)
That being said, no idea how Tesla accounts for small fluctuations like this, if at all. (Of course at low temps they make the available energy smaller and make that clear with the snowflake and whatnot.)
I mean, I know that doesn’t technically mean the capacity has actually increased. But if available energy is higher…
Ok.. I will be controversial (because I am bored)..if we look at the energy graphs…there are two horizontal lines..a dotted line called the average…and a solid line with no name..I will call it the EPA line…if you drive until your average line overlaps the EPA line and then read the range. If you then compare the range to the battery icon range then the difference is the amount of miles lost.
Am I wrong?
Am I wrong?
AlanSubie4Life
Efficiency Obsessed Member
SilverString
Member
I have a 3 1/2 year old MS with 56k miles. For a long time I worried about battery degradation as I lost range in the first few months of ownership. There was a steady decline in the first two years from 333 (never did have the 335 advertised when new) down to around 300, which is where it has stayed. This all according to the BMS, while at the same time Tesla telling me not to really believe the figure - that the BMS in my car has calibration issues that will likely be resolved with future software updates (not), and that my battery is is excellent condition.
I actually believe Tesla now because I have recently completed several 308 mile trips on a 95% charge with a few percent left over on arrival. This is in Iowa/Missouri on flat highways with few elevation changes, and at an average of 70mph, A/C on with outside temps in mid to high 80's. At home I charge at 11kW, but regularly use my FUSC at nearby chargers and on road trips, and to date my total number of charge kilowatts is nearly 50% from superchargers.
I actually believe Tesla now because I have recently completed several 308 mile trips on a 95% charge with a few percent left over on arrival. This is in Iowa/Missouri on flat highways with few elevation changes, and at an average of 70mph, A/C on with outside temps in mid to high 80's. At home I charge at 11kW, but regularly use my FUSC at nearby chargers and on road trips, and to date my total number of charge kilowatts is nearly 50% from superchargers.
A (really) cold battery wont be able to deliver all energy. Thats the snow flake (cell temp about freezing or colder). But the energy comes back when the battery warms.
The energy possible to deliver from a battery with normal temperature or higher temperature does not really differ.
Higher temperature will lower the internal resistance = slightly less heat loss( means slightly more energy out) and also, more power. At very low SOC you might feel the difference as less reduction of power.
For the increase of range when the BMS changes the cars on screen range due to a bms calibration etc, the real range the car can travel will not increase.
The battery has a starting capacity when we buy it, and from this the capacity will only go down.
The indicated range might go up and down but the capacity (= base for real range) will not go up and down, only down.
I did a simple read line(not an exact drawing) of my batterys reduction in capacity to my measured 79kWh capacity a month or so back.
I do not plan to perform a BMS calibration but if I did or if the range comes back it will only be a on screen range change, the real capacity will still be about 79kWh and tge real range will be according to this both before and after the increased range.
Ok...here is a variation of my theory....first take the energy graph, and find the value of the solid horizontal line (do this by driving until you can get the dotted line to cross the solid line and read the Wh/mile)...then drive until the range on the energy graph equals the range on the battery icon. Read the Wh/mile.Yes
The dotted line Wh/mile is divided by the solid line Wh/mile....the result equals the remaining percentage in the battery.
Am I wrong
AlanSubie4Life
Efficiency Obsessed Member
Yes, you are wrong.Am I wrong
That ratio will be equal to x / (x+5 Wh/mi) where x is in Wh/mi. For my car x is 245Wh/mi.
Will have nothing to do with % remaining in battery.
(Projected Range * Recent Wh/mi) / Battery "Range" = Vehicle Charging Constant
So if Projected Range (mi) = Battery Range (rmi), then Recent Wh/mi = Vehicle Charging Constant (Wh/rmi).
QED.
Those numbers will take me a month to digest...Yes, you are wrong.
That ratio will be equal to x / (x+5 Wh/mi) where x is in Wh/mi. For my car x is 245Wh/mi.
Will have nothing to do with % remaining in battery.
(Projected Range * Recent Wh/mi) / Battery "Range" = Vehicle Charging Constant
So if Projected Range (mi) = Battery Range (rmi), then Recent Wh/mi = Vehicle Charging Constant (Wh/rmi).
QED.
Ok Vegas guy here..back again for questions to make us think.
2022 MYP with 7500mi. These days 50% SoC gives me 134mi. Battery indicator is always set to % and never miles.
Planning weekend roadtrip to Disney in CA this Sat AM. I think we concluded from a few months ago that my BMS is miscalibrated. My 12% degradation cant be real. My max charge has been always to 50% SoC at planned AM departure since week 3 of owning car. 7 Supercharging sessions in life.
Two questions:
1. Since I plan to Tesla level 2 charge at home to 95% (maybe 100%?) before I depart, anything special I should do here to get some good top end BMS calibration data. Thinking at least have it sit at this charge for a few hours.
2. Could miscalibration impact my actual driving range when I get to the lower SoC on the drive? There is a Supercharger on the way that has a Starbucks that I have only been to once but prefer to stop at since I can top up nicely there and even avoid charging again around disney for few nights before driving back home. When I drove to this supercharger only one time from my home, I went from 100% to 10% at arrival and shitting bricks in the desert the last 30 miles driving below speed limit. Its 185 miles to that supercharger. Strong 20mph headwind, elevation, and AC impacted range with speed around 72mph. My miscalibration is worse now from that time (was ~2000mi odometer). Will my current worse miscalibration hurt my arrival SoC/batt available reading and making it seem lower that it may be? Could I actually be at a higher available battery then the indicated 10%? (And I know I can add a super quick earlier charging stop but I feel the car should be able to handle this one stopper without making me uncomfortable.)
2022 MYP with 7500mi. These days 50% SoC gives me 134mi. Battery indicator is always set to % and never miles.
Planning weekend roadtrip to Disney in CA this Sat AM. I think we concluded from a few months ago that my BMS is miscalibrated. My 12% degradation cant be real. My max charge has been always to 50% SoC at planned AM departure since week 3 of owning car. 7 Supercharging sessions in life.
Two questions:
1. Since I plan to Tesla level 2 charge at home to 95% (maybe 100%?) before I depart, anything special I should do here to get some good top end BMS calibration data. Thinking at least have it sit at this charge for a few hours.
2. Could miscalibration impact my actual driving range when I get to the lower SoC on the drive? There is a Supercharger on the way that has a Starbucks that I have only been to once but prefer to stop at since I can top up nicely there and even avoid charging again around disney for few nights before driving back home. When I drove to this supercharger only one time from my home, I went from 100% to 10% at arrival and shitting bricks in the desert the last 30 miles driving below speed limit. Its 185 miles to that supercharger. Strong 20mph headwind, elevation, and AC impacted range with speed around 72mph. My miscalibration is worse now from that time (was ~2000mi odometer). Will my current worse miscalibration hurt my arrival SoC/batt available reading and making it seem lower that it may be? Could I actually be at a higher available battery then the indicated 10%? (And I know I can add a super quick earlier charging stop but I feel the car should be able to handle this one stopper without making me uncomfortable.)
I dont think you need to let it sit at 100% for a few hours, I think you just need to plan enough time for it to charge to 100% and actually finish charging / balancing. Its possible (likely in your case I would think) that when your car gets to 100% it wont stop charging, it will continue to show charging as it will be balancing the cells.
Set your 100% charge to finish something like 1.5 to 2 hours before you are going to leave, to give it plenty of time to actually stop on its own. That should be fine for the balancing part of that.
I dont have any feedback on point 2, I will leave that to someone more versed than I am.
AlanSubie4Life
Efficiency Obsessed Member
I think it definitely could. At least part of it is real so your battery certainly has less capacity than it did when you last made the trip.
You should have no problem doing one stop assuming no vicious headwinds. Just start at 100%. You can see if you can make Hesperia, but if not just stop south side of Barstow - you’ll know by Barstow.
If possible, take pictures (showing miles on the screen) at:
1) Start
2) At each Supercharger stop
3) Trip page details at each (and every) stop before it resets (when you get out of car it will start the reset process, and will complete when you put in drive).
If you get all the details, should help get details on whether this is miscalibration or not. If some of the info is missing it will remain a mystery!
Run some simulations in ABRP, to test some of your ideas. If the goal is to make Hesperia for coffee and to top up for extra charge around Anaheim, why not just make 2 stops, the first stop being a short one, that'll allow you to start with a lower charge. Seems like less risk and worry if you just plan on 2 stops.
Okay, I just did it, Vegas to Anaheim, start at 80%, get to Anaheim with 30%, 16min stop in Baker, 12min stop in Hesperia. Drive fast, 13% over speed limit, and get there in 5hrs, 4h33m driving, 28min charging. And, I threw in 12% deg.
Thanks for the feedback from all.
2022 MYP. 7600mi. Purchased April 2022.
Vegas To Disney AM Pre Drive:
I did charge to 100% overnight. Felt very stupid and crazy to do this but overnight temps are thankfully in the mid 60F now in Vegas and left the car outside to charge for max cool effect instead of garage. Car has been sitting like this for about 2.5 hours asleep (no sentry mode at home but still plugged in and app not touched).
Range at 100% shows 271.
That is the same number I have been calculating within a couple miles with basic math using miles and %SoC through the battery graphic. Miles Divided by %SoC Multiplied by 100.
271/303 = 89.4%
10.6% degradation for a very babied battery. Hope actual is half.
Enjoying my coffee and will be hitting road soon. Have not decided where I want to charge yet between Hesperia or Barstow but will probably be Barstow to 80% and then to Disney parking lot.
2022 MYP. 7600mi. Purchased April 2022.
Vegas To Disney AM Pre Drive:
I did charge to 100% overnight. Felt very stupid and crazy to do this but overnight temps are thankfully in the mid 60F now in Vegas and left the car outside to charge for max cool effect instead of garage. Car has been sitting like this for about 2.5 hours asleep (no sentry mode at home but still plugged in and app not touched).
Range at 100% shows 271.
That is the same number I have been calculating within a couple miles with basic math using miles and %SoC through the battery graphic. Miles Divided by %SoC Multiplied by 100.
271/303 = 89.4%
10.6% degradation for a very babied battery. Hope actual is half.
Enjoying my coffee and will be hitting road soon. Have not decided where I want to charge yet between Hesperia or Barstow but will probably be Barstow to 80% and then to Disney parking lot.
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