Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Performance not getting 310 miles promised

This site may earn commission on affiliate links.
Status
Not open for further replies.
I've been paying a bit closer attention to this just for geek data on this charge, and I'm now curious what the wh/m target would be for the stated range.

Last Friday I charged the car to 90%, I haven't charged since, so I'm also dealing with vampire drain which based on checking the app isn't that bad. The car is now at 37% battery and I've driven ~130 miles. The average for this period is 262 wh/mile which to me represents fairly efficient driving. That means 53% battery usage yields 130 miles of driving. That means that 100% range in these conditions is 245 miles. Reducing that to 80% (as you'd ideally charge to 90% and recharge at 10%), yields a 196 mile range. This doesn't factor in the idle/vampire drain which is probably 3-5 miles per day. I don't pre-warm the car as the weather this week in Austin has been fabulous, so it's really just driving and vampire in ideal weather conditions.

I don't drive a lot and I bought this car with the intention of charging once per week, so for me 150-175 miles of range with a lot of comfort-level is fine for me, but I really have been driving the car very efficiently. I get 180-200 wh/mile on my 8 mile commute to work and 300-320 on the way home (uphill). Add in some weekend highway driving and I'm at 262 for the charge period.

Additionally, the car states in this 53% usage, 262 wh/mile that the car has used 34 kwh of power. So that math doesn't add up as I thought these things had like 85 kwh packs. One hypothesis is the 34 kwh usage reports only driving miles and doesn't include the idle/vampire drain. I've recently switched from remaining miles to energy % as I find it a better barometer and better allows me to try to calculate usage, but I'm finding I can't really make any of the math work out. It doesn't really bother me, just posting for another data point. I've only got 500 miles on the car and this is the first charge that I've been monitoring.
 
I've been paying a bit closer attention to this just for geek data on this charge, and I'm now curious what the wh/m target would be for the stated range.

Last Friday I charged the car to 90%, I haven't charged since, so I'm also dealing with vampire drain which based on checking the app isn't that bad. The car is now at 37% battery and I've driven ~130 miles. The average for this period is 262 wh/mile which to me represents fairly efficient driving. That means 53% battery usage yields 130 miles of driving. That means that 100% range in these conditions is 245 miles. Reducing that to 80% (as you'd ideally charge to 90% and recharge at 10%), yields a 196 mile range. This doesn't factor in the idle/vampire drain which is probably 3-5 miles per day. I don't pre-warm the car as the weather this week in Austin has been fabulous, so it's really just driving and vampire in ideal weather conditions.

I don't drive a lot and I bought this car with the intention of charging once per week, so for me 150-175 miles of range with a lot of comfort-level is fine for me, but I really have been driving the car very efficiently. I get 180-200 wh/mile on my 8 mile commute to work and 300-320 on the way home (uphill). Add in some weekend highway driving and I'm at 262 for the charge period.

Additionally, the car states in this 53% usage, 262 wh/mile that the car has used 34 kwh of power. So that math doesn't add up as I thought these things had like 85 kwh packs. One hypothesis is the 34 kwh usage reports only driving miles and doesn't include the idle/vampire drain. I've recently switched from remaining miles to energy % as I find it a better barometer and better allows me to try to calculate usage, but I'm finding I can't really make any of the math work out. It doesn't really bother me, just posting for another data point. I've only got 500 miles on the car and this is the first charge that I've been monitoring.
EPA docs says the car has an 80 kWh battery, Tesla says 75. So doing some math from Teslas number yields 242 Wh/mi as the number needed to meet stated range 258 Wh/mi from the EPA number. In the energy app I believe rated line is a little below 250 Wh/mi.
 
  • Informative
Reactions: hoang51
I've been paying a bit closer attention to this just for geek data on this charge, and I'm now curious what the wh/m target would be for the stated range.

Last Friday I charged the car to 90%, I haven't charged since, so I'm also dealing with vampire drain which based on checking the app isn't that bad. The car is now at 37% battery and I've driven ~130 miles. The average for this period is 262 wh/mile which to me represents fairly efficient driving. That means 53% battery usage yields 130 miles of driving. That means that 100% range in these conditions is 245 miles. Reducing that to 80% (as you'd ideally charge to 90% and recharge at 10%), yields a 196 mile range. This doesn't factor in the idle/vampire drain which is probably 3-5 miles per day. I don't pre-warm the car as the weather this week in Austin has been fabulous, so it's really just driving and vampire in ideal weather conditions.

I don't drive a lot and I bought this car with the intention of charging once per week, so for me 150-175 miles of range with a lot of comfort-level is fine for me, but I really have been driving the car very efficiently. I get 180-200 wh/mile on my 8 mile commute to work and 300-320 on the way home (uphill). Add in some weekend highway driving and I'm at 262 for the charge period.

Additionally, the car states in this 53% usage, 262 wh/mile that the car has used 34 kwh of power. So that math doesn't add up as I thought these things had like 85 kwh packs. One hypothesis is the 34 kwh usage reports only driving miles and doesn't include the idle/vampire drain. I've recently switched from remaining miles to energy % as I find it a better barometer and better allows me to try to calculate usage, but I'm finding I can't really make any of the math work out. It doesn't really bother me, just posting for another data point. I've only got 500 miles on the car and this is the first charge that I've been monitoring.

Meters don’t included energy used when car is in park.

We have 75kWh packs (usable; actual pack is probably slightly larger). So Tesla’s scalar should be 75kWh/310mi =242Wh/mi. You’ll see this is about where the “target” line is on the energy display. (Maybe some debate on the EXACT numbers, but it doesn’t matter. The line is below 250Wh/mi and above 235Wh/mi, for sure.)

0.9*75kWh = 67.5kWh
0.37*75kWh = 27.75kWh

Used energy: 39.75kWh

130mi*262Wh/mi = 34.06kWh

Used Energy = Driving Energy + Other Losses

Other losses = 39.75kWh-34.06kWh = 5.69kWh

You’ve lost 14% of your consumed energy to heating while parked, sitting while parked, vampire drain, etc.

Tesla says you should expect 1% loss per day, which is 0.01/day*310mi * 242Wh/mi = 0.75kWh/day, so you’d expect at least 3kWh loss from that over 4-5 days (and that assumes no touching of the car I would think). I’d expect more; 4kWh seems totally possible over that timeframe. That’s just 1.69kWh unaccounted for, which is easy to burn just sitting in the car for a bit, running heat for a few minutes while parked, or whatever. EDIT: there is also rounding error on the %, that’s why displaying rated miles is about 3x better for these calculations.

It all checks out. Easy stuff, just have to know how things are counted.
 
Last edited:
  • Informative
Reactions: hoang51
Meters don’t included energy used when car is in park.

We have 75kWh packs (usable, actual pack is probably slightly larger). So Tesla’s scalar should be 75kWh/310mi =242Wh/mi. You’ll see this is about where the “target” line is on the energy display. (Maybe some debate on the EXACT numbers, but it doesn’t matter. The line is below 250Wh/mi and above 235Wh/mi, for sure.)

0.9*75kWh = 67.5kWh
0.37*75kWh = 27.75kWh

Used energy: 39.75kWh

130mi*262Wh/mi = 34.06kWh

Used Energy = Driving Energy + Other Losses

Other losses = 39.75kWh-34.06kWh = 5.69kWh

You’ve lost 14% of your consumed energy to heating while parked, sitting while parked, vampire drain, etc.

Tesla says you should expect 1% per day, which is 0.01/day*310mi * 242Wh/mi = 0.75kWh/day, so you’d expect at least 3kWh loss from that over 4-5 days (and that assumes no touching of the car I would think). I’d expect more; 4kWh seems totally possible over that timeframe.

It all checks out. Easy stuff, just have to know how things are counted.

Perfect, that helps and does all add up. As stated, I tend to lose ~3 miles per day sitting in my garage.
 
View media item 119269
This is from a trip I recently did in one day

Started at 100% 75000 watts
drove 126 miles
stopped 2 hours
drove back 126 miles
finished with 11% 8250 watts

trip shows i used 62000

so 4750 watts or 6.3% of battery went to vampire drain in 2 hours?? that can't be right. There must be some kind of buffer where there is still watts available but state of charge shows zero.

I was impressed with the efficiency ... average 72-75 mph on freeway 98% of trip. 55-60 degrees outside. LR RWD aeros
 
View media item 119269
This is from a trip I recently did in one day

Started at 100% 75000 watts
drove 126 miles
stopped 2 hours
drove back 126 miles
finished with 11% 8250 watts

trip shows i used 62000

so 4750 watts or 6.3% of battery went to vampire drain in 2 hours?? that can't be right. There must be some kind of buffer where there is still watts available but state of charge shows zero.

I was impressed with the efficiency ... average 72-75 mph on freeway 98% of trip. 55-60 degrees outside. LR RWD aeros



I've heard our battery was 73.5kWh usable. I've heard 75kWh usable. I've also heard 80kWh usable. Honestly, your numbers make me believe we have 80kWh, and you were calculating for 75.....which would explain the "missing" 4750.
 
I know if it was sitting then having the heat on HI will use nearly that amount of energy if used for 30 minutes and will not show up on that meter as the car wasn't moving.

My heat on HI uses nearly 8 kW so in 30 minutes you'd use about what you lost. Did you preheat the car at all?
 
No preheat. Did not lose any percentage during the 2 hour stop.

When leaving the car showed 100% for maybe a block before going to 99%

I'm not complaining btw - I'm amazed by the range and efficiency of this car. We know they have at least 70 kWh available.
 
View media item 119269
This is from a trip I recently did in one day

Started at 100% 75000 watts
drove 126 miles
stopped 2 hours
drove back 126 miles
finished with 11% 8250 watts

trip shows i used 62000

so 4750 watts or 6.3% of battery went to vampire drain in 2 hours?? that can't be right. There must be some kind of buffer where there is still watts available but state of charge shows zero.

I was impressed with the efficiency ... average 72-75 mph on freeway 98% of trip. 55-60 degrees outside. LR RWD aeros

I can't comment on why your numbers show up this way. Just do your own experiments and make absolutely sure you spend ZERO time in park. If you spend time in park the numbers can be off by a lot.

My experiments done this way indicate that the extrapolated value for a full discharge is right around 75kWh. It's possible if the battery state of charge is a little off it might meter it wrong? Or more likely, you spent some time in park.

Case in point (you'll have to take my word for it), I started at 91% charge for this trip pictured below (P3D+). So 0.81*75kWh = 60.8kWh. (There is rounding error here due to just 2 sig figs on the %.)

The meter shows I used 59.9kWh. I did spent a certain amount of time (probably about 10-15 minutes) in park with the AC (and also the heat) on.

In my experience, you can't spend ANY time in park if you want to make these numbers add up; or you have to be 100% sure your climate control is off while you're parked. Even then any time spent in park will introduce error.
IMG_3735.jpg
 
However, we don't need to debate the usable capacity that Tesla gives, or do experiments to determine it. All you need to know is the position of the "rated" line in the energy graph, and multiply by 310 miles (Tesla's stated rated range for 100% - though some cars may have slightly more or less).

70kWh/310mi = 226Wh/mi
80kWh/310mi = 258Wh/mi
75kWh/310mi = 242Wh/mi

I think we can all agree on which number the line is closest to. Just keep an eye on it during driving and look for a time when your actual average is such that it lies very close to the line. You're going to find it is closer to 242Wh/mi than those other numbers.

Whether the line is actually EXACTLY 242Wh/mi, I do not know. You can't zoom in so you can't tell. But the resolution is such that you can tell when your actual economy is above or below that line, within a few Wh/mi.
 
  • Like
Reactions: ModelNforNerd
You should check your elevation at work and at home, by the way. To me it looks like this is largely a downhill run, for that economy & speed (though drafting could have been helping too). But for the P3D+ I doubt it is just drafting. So if you see more on the way home you know why.

It is 1.6kWh (6.6 rated miles) or so per 1000 feet for the AWD/P3D, unless you are carrying rocks. You have to distribute it by number of miles and add/subtract to your drive economy to correct for it.

Yea elevation might the thing, the way back got 300 Wh/mi. Got some business matters now, can't wait to 10% and supercharge for now, will do next time. Yesterday I charged from 12% to 97% this morning, oddly not 100%.... it said 10 hrs and I let it charge more than 12-14 hrs.. I know last % takes longer, but didn;t have that issue with previous LR RWD. Anyway will be posting back once I supercharge it and drive more, as now is only 1,300 miles.
 
Status
Not open for further replies.