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Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health
- Thread starter KK_RedM3
- Start date
I can only relay what Tesla service has told me. When I was only charging to 280 miles at 100%, I took it to the service center for a battery diagnostic... they said battery was fine.
My battery status from my Tesla Fi. unfortunately I signed up when I has 7k miles on my car so that's how far back my history goes...
This says 179. 179 is not 280. 179 is broken. 280 isn't.
Driving style has nothing to do with it. You are being lied to (or more likely someone who has no clue what they're talking about is telling you what they believe to be true. The only range displayed anywhere but within the energy app is EPA rating and doesn't vary based on how you drive at all.
AlanSubie4Life
Efficiency Obsessed Member
And....crickets...maybe @XLR82XS has me on ignore?
Would also be good to see a screen capture of that projected miles available showing ~322 in the app when you slide the slider to 100%, I suppose. Or some other way to show the 320 miles at 100%.
SleeperService
Member
Just charged from 11% to 90% a couple days ago. Still holding steady at 270 rated miles at 90% charge. Interestingly, at 11% it was showing 34 rated miles remaining, which calculates out to 310 miles at 100%. @AlanSubie4Life does the kwh charged actually mean energy into the battery, or is that wall energy? Because that calculates out to 58/79% = 73.4 kwh capacity, which seems pretty good. Are we certain on the actual nominal energy capacity of the LR Model 3 battery? Is it 75 kwh?
AlanSubie4Life
Efficiency Obsessed Member
You're subject to a lot of precision error when you have just two significant digits for both numbers (34 miles at 11%) - for example 33.6 rated miles at 11.4% works out to 295 rated miles at 100%.
This screen will always show ~245Wh per rated mile added as far as I can tell (for the AWD). This is roughly energy into the battery, and is definitely not wall energy.
The buffer is usually about 3.5kWh per the CAN bus. In discharge rated miles, that's 3.5kWh/234Wh/rmi = 15 rated miles
After accounting for the buffer, that calculates out to 245Wh/rmi*310rmi + 245Wh/rmi*15rmi = 79.6kWh for a full charge from fully exhausted, with a new battery. Presumably you'd see 325 rated miles added on the charging screen if you started with a completely depleted battery (and you'd have a terminal battery gauge reading of 310 rated miles). No one has described how this charging screen behaves when you start below 0 rated miles. But probably if you read the CAN bus back after such a charge you'd see you had 76-77kWh available including the buffer, not 79.6kWh.
The EPA test conducted by Tesla in their Fremont lab showed that the AWD battery capacity was 79.2kWh for a vehicle with 4000 miles on it.
So I guess it aligns sort of well, but to be honest it's super confusing, with all the charging and discharging constants, and depending on what you're looking at, the various numbers appear to represent kWh with slightly different scalings.
There's really just one small unknown for me that I can't make sense of right now and that's how a brand new battery can have 77kWh+ capacity - it seems like it should cap out at ~76kWh for the CAN readbacks with what we know about readbacks for vehicles whose batteries have aged slightly. But I've seen readbacks of capacity over 77kWh.
I'm down to 248 @ 90%. It was 262 for the longest time, but about 1 week ago there was a huge drop.
2018 Performance with 15k miles.
Not true. I saw a 4% range decrease within the first 4 months of ownership, and have seen a slow, but steady decrease in range. So, I reach out to Tesla every couple of months to inquire about my battery health, and I've been told this numerous times:
"Thank you for reaching out to Tesla Support. We do greatly apologize for the delay in responding to your email. There are many factors involved in the actual range of your Tesla, and why you may feel that your actual range or charge capacity does not match up to the high voltage pack capacity. The battery pack is sized to provide range. Our range is carefully calculated and measured according to rigorously reviewed standards. In contrast, a vehicle’s battery pack energy capacity varies with the rate of discharge and cell temperature. The range should not viewed as an Odometer as the range shown is an estimation of miles that can be driven after the Tesla has analyzed the outside environment, features normally used, and driving style."
jonquiljo
Active Member
That's a pretty large "sudden" drop. Anything you can think of to account for it?
Software version 2019.40.2?
Maybe Tesla is finally indicating the actual range you will achieve based on lifetime Wh/mi?
Honestly no clue why the sudden drop. I first noticed range loss within 4 months of ownership when the car would only get 268 mi at 90%. Since then, it fluctuated between 268-272 for a few months, then it went down consistently to 262 for a few months, and the other morning it was 248. I also charged it during warmer daytime hours, and it was still at 248.
I'm convinced that Tesla will say this is "normal", but I will still log it and have them review it, so I can keep the log/trail alive.
jonquiljo
Active Member
AlanSubie4Life
Efficiency Obsessed Member
Quickly answering this part of the question, since you have 300 miles at a full charge your battery per the CAN bus readback is probably at 73.5kWh. This is down from ~76kWh to 77kWh from that readback when new.
So you've got about 3.3% degradation. And your buffer might be 3.4kWh rather than 3.5kWh.
You've got about the same rated miles at 100% as I have.
AlanSubie4Life
Efficiency Obsessed Member
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