Is this normal range loss within a single drive?

[hcdavis3]

I do too. I pay $0.26 / kWh and SuperChargers are $0.32 / kWh.

It is worth understanding how to best optimize your car and understand the trade offs, it's not just about your wallet either.

Eversource is wickid expensive. I think here in MA our rates are second only to Hawaii.

 

[SoManyM3s]

It is normal, really...and the above is a key difference in addition to the huge temperature difference.

If he had driven the EXACT same drive as you at 255Wh/mi, he would have used:

223/209 * 150rmi. = 160 rated miles (not your 150 rated miles). To travel 120. So that is part one.

But he did 299Wh/mi - but he was using the heat!!! At 40 degrees outside that is a steady state 3kW or so. At 70mph that is 3kW/70mph = 43Wh/mi

255Wh/mi + 43Wh/mi = 298Wh/mi

QED?

If he had done the same distance drive you did at 299Wh/mi, he would have used 172 rated miles.

Also by my calculations you should have used closer to 140 rated miles, not 150. Obviously pretty common to be a bit higher in reality with time spent in park and prewarming the cabin.

255Wh/mi/223Wh/rmi*120mi = 137 rated miles.

Thank you for the analysis. I totally missed where outside temperature was 40F. I thought it was 68F, but that was his set temperature.

Appreciate your calculations. I mapped it and apparently it's a 129 miles drive for me and not 120. And I used about 150 so your calculations are correct.

 

[Mikedrives]

Thanks all for your thoughtful replies. This is my wife's car and I have little time to drive it or goof around with it/learning it, but having some fun along the way. I will go a little deeper in the sticky threads to bone up.

FWIW, it was my wife driving while I was spying on her from the app, sitting at home. The 105 miles was done in the middle of her drive, no idling, no pre-heating, no traffic. Tire pressure was 1-2 lbs above recommended. I see now from my screengrabs she was at 70ºF cabin temp- she's a bit cold-blooded, but only uses the seat heater at the start of cold morning drives, when she leaves for work in the dark- can't blame her!

Burning through 150 miles in 105 miles just seemed a little beyond normal when not hotrodding it, and made me wonder if you ever get the miles represented under the best of conditions. Wouldn't have guessed that heating to 30º above exterior temps costs you 30% range, all other things being *almost* equal. Will try to do something similar in warmer temps when they come. Thanks again - the hive mind wins again.

 

[AlanSubie4Life]

Wouldn't have guessed that heating to 30º above exterior temps costs you 30% range, all other things being *almost* equal.

It's possible empirically to measure this. I've measured heating the cabin to 70 degrees with outside temp of 55. That takes 2kW, continuous, after the car is fully warmed. It's not unlikely that 70 vs. 40 would take 3kW. At an average speed of 60mph, that's 3000W/60mph = 50Wh/mi. For a trip of 105 miles, that's 5.25kWh. That works out to be 5.25kWh/245Wh/rmi = 21 rated miles over the course of this trip. That's a minimum number; initially the draw will be higher. If the AC was in use, it will be higher still.

It matters.

and made me wonder if you ever get the miles represented under the best of conditions

You can. You just have to repeat the conditions of the EPA test, and that certainly does not include driving at 70mph.

 

[garth_angst]

I usually figure 70% efficiency at this time of year. 70% of 150 = 105, so you are right on the mark.

(You will learn over time that the energy consumption is very sensitive to temperature, heat/AC use, speed, and elevation gain).

I noticed almost no range loss during the summer with my A/C use. I do not recall the temp I used and I didn't use it every single trip.

 

[coconutboy84]

Lol mass disliking my posts. How childish.

 

[HopeToGolf]

A few times a quarter I need to take long trips (>350 miles). These trips require that I use a Supercharger along the way. Generally, in winter while on snow tires, keeping a cabin temp of 70 degrees, and driving 79 in a 65, I will budget an additional 33% of distance when looking at my range needed for my trip. This is true if I have to cut it razor thin to hit my destination but more likely 50% to be safe for diversions, hitting higher speeds, potential issues at the Supercharger, and just to be totally safe and comfortable.

The point is, if you want to optimize efficiency, there is much to think about with respect to the way you drive, outside conditions (elevation, temperature, wind, etc.) and the creature comforts you use while driving. This is true especially in colder geographic locations.

The best thing I read before buying the Model 3 was to buy as much range as I could afford. This is especially true for those of us who are less green and less willing to compromise on our driving style and habits.

 

[Mikedrives]

Can you direct me to those? I've looked around some and not found anything except that it's done on a dynamometer. Nothing concerning temperature, except one mention of it being done at room temperature.

The EPA site has tons of interesting stuff, including a test of two steam-powered VWs built by a guy in Tennessee in 1976, boiling water on a 50/50 gas/kerosene mix. (The cars performed well on the emissions test!)

But I couldn't find anything indicating how I might approach replicating the EPA conditions. TIA.

 

[AlanSubie4Life]

This document is an example of one that contains all the information needed to understand what they did. You will probably have to look up additional SAE documents referenced, on the details of the drive cycle (it's a standard cycle). The formulas in the spreadsheet are not visible, but they are standardized formulas (including weights of the different UDDS cycles, etc.), used by manufacturers - which can also be looked up.

https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=46075&flag=1

Highway cycle quick pic:

Emission Test Cycles: EPA Highway Fuel Economy Test Cycle

You can dig into this arbitrarily deeply, really.