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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
All seems normal other than your 100% charge (which is ~478km instead of 520km) - which is also pretty common:
0.77*478rkm*146Wh/rkm / 277Wh/km = 194km
0.86*478rkm*146Wh/rkm / 262Wh/km = 229km
0.86*478rkm*146Wh/rkm / 244Wh/km = 246km
478 instead of 520 is 8% loss in the available energy estimate. Battery is probably about 3.1kWh + 478rkm*139Wh/rkm = 69.6kWh full available energy including the buffer (which you don't want to use, so call it 66.5kWh usable).
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On a long range 3 you're only getting 300km? SR+ has an advertised range of 400. That's concerning.
AlanSubie4Life
Efficiency Obsessed Member
No, he has 478km of rated range (430km at 90%). If starting at 77%, he drives at 277Wh/km, he gets about 196km of range (less than that to get to 0%), as one would expect.
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What I don’t understand is how my Wh/km is so high. I drive city speed and some high on my daily commute. My vehicle life energy is 43,755 km with 6,985 kWh and 160 Wh/km.
Also how can you tell it’s normal by looking at the graphs. How do you do the calculation.
AlanSubie4Life
Efficiency Obsessed Member
It is 4-6C outside and 23C in the car is likely the primary reason. Try prewarming your car, turning off climate control entirely, and compare again.
The formulas are in the above post. Just need to know that 146Wh/rkm constant (234Wh/rmi) for the LR RWD. You can actually back calculate the the value of this constant from that screen based on the three numbers available: Rated km remaining (next to battery gauge), average interval Wh/km (left side of graph), and the projected range (right side of graph).
5_+JqckQttqck
Active Member
It's winter time so heating will eat a chunk of battery, especially at 23°C!
If you're going to heat it to 20+, use recirculation with A/C. Heating is the most intensive Wh use.
Also change to 50km to get a more stable projected range for a road trip. Otherwise, little short trips in the city will zap more battery as the car systems need a warm up period to perform at optimal levels. Mostly battery temperature warm up.
Forgot where I grabbed these numbers from, (sorry to the original writer/poster):
Baseline (vehicle at rest but powered up): 247 Wh
Defroster (rear window & side mirror heaters): 285 Wh
Steering Wheel Heater: 95 Wh
Heated Wipers & Nozzles: 95Wh
1 Seat Heater: 57 Wh
2 Seat Heaters: 133 Wh
3 Seat Heaters: 171 Wh
4 Seat Heaters: 209 Wh
5 Seat Heaters: 247 Wh
HVAC at ‘HI’ or 82F (28C): 6,400 Wh
HVAC at 74F (23C): 342 Wh
Happy winter driving!
SageBrush
REJECT Fascism
5_+JqckQttqck
Active Member
You can say Watts.
Watt hour is just an alternative to say X device consumes Y Watts over 1 hour of time.
Watt hours (Wh) = work over time. Watts is just work (V *A; instant at x time). Similar but slightly different context.
Watt hours is being more precise. You can have a plug give you 240V * 32A and have either the voltage or amperage fluctuate. In the instant, you're getting 6.6watts of power. But to actually charge 6.6 watts into the battery. It takes 1 hour. Thus the car displays Wh.
EDIT: Example using the above numbers (even though their from a Model S, lets assume the 3 use similar parts).
It snowed overnight and in the morning I use the app and preheat cabin and turn on front and back defrosters for 15 minutes while getting up.
Baseline (vehicle at rest but powered up): 247 Wh
Defroster (rear window & side mirror heaters): 285 Wh
1 Seat Heater: 57 Wh
HVAC at ‘HI’ or 82F (28C): 6,400 Wh
Sum = 247+285+57+6400 = 6989 * 0.25hr = 1747Watts (for those 15minutes used)
Since my car was plugged into a 110V/12A charger; which is 1320Watt hour supply. multiply again by 0.25 = 330Watts from the wall.
So, 1747-330 = 1447watts that came from my battery pack.
Given the rated Wh/km = 150. 1447/150 = 9.65kms of "rated" range was used to preheat/defrost for those 15 minutes.
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SageBrush
REJECT Fascism
Sure, but then you have to clarify that the energy consumption is for an hour.
I just remembered a table for appliance consumption Tesla posted on their website a couple of years ago in the powerWall section. It said things like "fridge: 3 kWh per hour."
I imagine that the content author was fired by Elon.
296miles (476km) @100% for May 2018 build, LR RWD.
2019.32.12.2
Handful of super charges (~10). Only charged to 100% twice, right before a long trip to test/calibrate the battery capacity.
It was not a gradual drop.
I usually charge at home (32A) to 80% and get 383km. Extrapolating this to 100% gets to the same number I got when I actually charged to 100%.
I wish there was a better way to confirm the battery health is okay.
2019.32.12.2
Handful of super charges (~10). Only charged to 100% twice, right before a long trip to test/calibrate the battery capacity.
It was not a gradual drop.
I usually charge at home (32A) to 80% and get 383km. Extrapolating this to 100% gets to the same number I got when I actually charged to 100%.
I wish there was a better way to confirm the battery health is okay.
Your response aligns with comments service centre today when I spoke to them. They mentioned that it's probably using the energy to heat the battery, hence increase Wh/km usuage. I also learned that even though the charge finish charging at 6am in the morning before my commute, i still need to precondition the batteries for at least 20 mins. 30-45min is better. I'm going to leave it plugged in.
I'm going to try to precondition the batteries for the next couple weeks and see if it changes anything. I didn't know that the battery needs precondition even though it's like 8-10 degrees outside although I do park inside my garage. I do notice at times that the range increase when I have my ventilation system off. Will report back my findings. It doesn't seem like anything I need to be concerned with at this point though.
5_+JqckQttqck
Active Member
Check your VIN vs these two service bulletins. May affect range if certain cells have disconnected from the main pack.
https://static.nhtsa.gov/odi/tsbs/2019/MC-10154513-9999.pdf
https://static.nhtsa.gov/odi/tsbs/2018/MC-10148848-9999.pdf
SageBrush
REJECT Fascism
Interesting, although my read of the TSB is that the connects are missing from the factory.
Rojer Lockless
Member
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