What are people using to gauge their battery degradation\capacity? I have been using ABRP app, and it reports 7.1% battery loss, however my 90% rated range is around 251 miles on my 2018 stealth P3D with 18k miles. My calculation is that is around 280 miles rated range at 100%, which from the graph above looks pretty far below the fleet average, and probably closer to >10% loss? A lot of that loss seems to have happened over the last few months even though i haven't been driving it much (I super charged it a few times, usually at an urban charger). I just did a few ~2 hour trips and i was hoping it might rebalance, but it doesn't seem to have made any difference. I'm wondering if i should make a service appointment, but i'm guessing they will just tell me everything is within spec?
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health
- Thread starter KK_RedM3
- Start date
Candleflame
Active Member
Just look at the rated range. For kwh without tmc you can just charge to 100% and use the energy consumption meter by timing est remaining range times.average wattage.
The closer you go to 0% soc the less of the buffer gets taken into account though so its really only accurate above 70%
diamond.g
Active Member
Yeah you can do what @Candleflame said, or you get get a OBD2 reader and SMT which flat out tells you the Nominal Full Pack. But the SMT way costs money. The maths way is “free”.
Candleflame
Active Member
Abrp uses supercharger data only afaik.
I have done my 100% charge yesterday and then 14h of driving yesterday. I did get around 4km after the 100% of range back. Car unfortuantely only went to sleep for 15min and then woke for 3h and then started sleeping again but it was time to leave.... On SMT my Kwh only went up from 69.4 to 69.6 kwh. Even though the 69.4 was displayed for 452km range and the 69.6 from 457km.
I have done my 100% charge yesterday and then 14h of driving yesterday. I did get around 4km after the 100% of range back. Car unfortuantely only went to sleep for 15min and then woke for 3h and then started sleeping again but it was time to leave.... On SMT my Kwh only went up from 69.4 to 69.6 kwh. Even though the 69.4 was displayed for 452km range and the 69.6 from 457km.
Last edited:
Another reson for wanting higher SOC when doing the calculation is that the resulotion of 1 % is 1/100 at 100% but only 1/10 at 10% SOC.
That said, I did a lot of calcs and compared to SMT, so I have some down to 40% and these calcs was more or less spot on also
AlanSubie4Life
Efficiency Obsessed Member
Also the buffer being partially accounted for as capacity is reduced is corrected for by dividing by SoC %, so that is not a source of error for battery capacity calculation - it’s only an error source if you are trying to figure out how much energy remains (the value calculated will be low).
For full capacity calculations, the only significant source of error (other than the error in the estimate itself), assuming Wh/mi and projected range are 3 sig figs, is the SoC % rounding error that you mention. At 40%, it is kind of luck of the draw...the error could be close to zero. Various people have also posted methods using the trip planner page of the Energy screen to interpolate the exact % (one extra significant digit), but I have personally never tried that method to see how well it works. Seems like it might work.
Last edited:
Depends how exact your anticipation of a good enough number is ?
At 40% the maximum fault wouyld be 1/40, around 2.5%. So the average fault should be about half or 1.25%. On a 70kWh nominal pack thats 0.87kWh. For the sake of the degradation calculation if your car has some age and has lost about 8%, the fault on the degradation will average 0,87kwh out of 6.2kWh, so the degradation calculation ends between with 7% or 9% on average. Worst case, 6% or 10%.
I dont recommend using low SOC for the calculation, just to show that it isnt extremely of anyway. The 70% statement might be change to ”the higher SOC the more exact result.
eethan
Member
Why does the SR+ get 263 mile range, but the MR is stuck at 264 miles range? (And my Nov '18 MR with 27k miles has now degraded to 241 miles at 100% charge)
Because the SR+ is newer and comes with a bigger, than the original SR+, battery and other efficiency improvements that your MR doesn't have.
Candleflame
Active Member
Harvey Danger
Member
Switch to percentage display and don't look back.
As for the 14 "miles" overnight.. sentry mode perhaps?
As for the 14 "miles" overnight.. sentry mode perhaps?
The short answer is: Probably.
The long answer is: Make yourself a big pot of fresh coffee, and start reading the sticky threads on the Model 3: Battery & Charging subforum. With the information you can find there, you'll be able to determine exactly what your battery's health is.
The medium answer: You know how new cars have stickers on them with the government miles per gallon ratings, that always end with the "your mileage may vary" statement? This also applies to electric vehicles. The EPA assigns a certain energy usage per mile driven under specific temperatures, and obtains an estimated range for that vehicle. Assuming your battery is in 100% health, if you then drive the car in the EXACT manner and atmospheric conditions that the EPA did to obtain those range estimates, your car should do the same. But the second you drive it outside of those parameters, the estimates mean exactly nothing.
Honestly, I think it's worth the time to spend a few minutes per day reading through the sub forum I linked above, and learning enough to really understand why your car gets the range it does for the way you drive it, how it charges the battery both at home and at super chargers, how super chargers share the available power between stalls, and a lot more very nice-to-know information. Don't be intimidated by the length of the threads... there's a lot of posts that you can skip. You can start by skipping all of the posts made by me, but pay extra attention to posts by @AlanSubie4Life
Enjoy your car!
Last edited:
bjrosen
Member
Here are some tips
1) For daily commutes set your charge level to 80%, it's better for the battery. Use 90% for road trips.
2) Keep your car plugged in at home.
3) Unless you live in a bad neighborhood turn off Sentry Mode at home, it keeps the car awake which vastly increases the phantom drain.
4) Look at the trip computers to see how much energy you are using. To get them swipe right on the bottom of the screen or use the voice command "Show Odometer". There are four sections, Energy used on this trip, Energy used since plugged in and Trip A and B. Leave Trip B alone, if you never reset it you'll have your statistics since you bought the car. Use Trip A for specific trips.
Energy usage is a function of speed, weather, HVAC usage, tire inflation. For speed remember that K=1/2MV^2, i.e. kinetic energy is a function of the square of the velocity, loses due to drag and friction all reduce down to some variant of this equation. Heating and cooling can use a lot of energy. I live in New England so cooling is basically free for most of the spring and summer because our ambient temperatures are in the comfortable range most of the time, there are a couple of bad weeks where it goes up to the 90s but mostly it's OK. Winter is really expensive for those of us without heat pumps, we lose about a third of our range if we turn on our heaters. You have the heat pump so it won't be that bad but heat isn't free as it is on an ICEV. I keep my tires at 41psi cold.
One final suggestion, if you are interested in tracking yoir range and energy usage install Tezlab on your phone and link it to your Tesla account. The free version only looks back one week, the premium version looks back forever.
1) For daily commutes set your charge level to 80%, it's better for the battery. Use 90% for road trips.
2) Keep your car plugged in at home.
3) Unless you live in a bad neighborhood turn off Sentry Mode at home, it keeps the car awake which vastly increases the phantom drain.
4) Look at the trip computers to see how much energy you are using. To get them swipe right on the bottom of the screen or use the voice command "Show Odometer". There are four sections, Energy used on this trip, Energy used since plugged in and Trip A and B. Leave Trip B alone, if you never reset it you'll have your statistics since you bought the car. Use Trip A for specific trips.
Energy usage is a function of speed, weather, HVAC usage, tire inflation. For speed remember that K=1/2MV^2, i.e. kinetic energy is a function of the square of the velocity, loses due to drag and friction all reduce down to some variant of this equation. Heating and cooling can use a lot of energy. I live in New England so cooling is basically free for most of the spring and summer because our ambient temperatures are in the comfortable range most of the time, there are a couple of bad weeks where it goes up to the 90s but mostly it's OK. Winter is really expensive for those of us without heat pumps, we lose about a third of our range if we turn on our heaters. You have the heat pump so it won't be that bad but heat isn't free as it is on an ICEV. I keep my tires at 41psi cold.
One final suggestion, if you are interested in tracking yoir range and energy usage install Tezlab on your phone and link it to your Tesla account. The free version only looks back one week, the premium version looks back forever.
Last edited:
Worth mentioning that's your personal opinion. Lots of sources, including Elon, say 90% is just the same for the battery life.
Especially for folks who like me who have an SR+ that is supposed to get to 240mi on a full charge but only get 210 miles at 100%, 188 miles at 90%.
I did that for a while, and it works for short daily commutes. However, seeing the rated mile is good when planning longer trips, since a number of us have seen large enough degradation (15% in my case) that a trip the car can make previously may no longer be the case now.
AlanSubie4Life
Efficiency Obsessed Member
Totally not related to Tesla, but just as a data point, my 4.5 year old Chevy Spark EV is approaching 40% capacity loss. It’s quite low mileage too (22.5k miles). It’s down to substantially less than 12kWh capacity, from its start around 18.5kWh. Warranty replacement is 40% loss, so we will see. Have 3.5 years to go. I like my chances. Lol. As long as it doesn’t catch on fire in my garage and immolate my Performance Model 3 I’ll be happy. Need to install a networked smoke detector in there.
All the more reason to register, for free, with ABRP. It'll automatically pull your car's data, including deg, ambient temps, calibrate your car's efficiency, determine your speed overage, and calculate whether you can or cannot make your regular trip.
Similar threads
