Lifetime Average Wh/mi

[jerry33]

can you please share the 30-mile energy graph from one of these days that you do your 25-mile commute at 200 Wh/mile?

Here's today's. Note that the going home part raises it a bit because it's 40C today and so A/C takes a bit, plus there is more traffic and the going home route has higher speed limits as well. Also, I didn't go straight home so the way back is a bit longer. I usually take the monthly picture when I arrive at work because that's when I remember to take it. Too bad the graph only does 30 miles, it would be better if it did 60 or 90, then you could see an entire day on one graph.

 

[gg_got_a_tesla]

Beautiful, Jerry; that's as flat as it can realistically get. My graph typically is so jagged that I can cut myself on it

 

[mknox]

Still... the far more important metric is "how far can I get with a given charge". By watching wh/mi over time you get a sense of how the car performs on a given road at a given speed, and vampire losses are almost irrelevant on the road. After a while you can predict what your wh/mi would be for a given trip, which helps in planning.

I think if someone really care about every kWh that is poured into the battery, you'll also care about the power loss in the cable and UMC as well. In that case what you need is a second meter - nothing the car can do will help with that.

I think brianman hit the nail on the head with the suggestion of two values. Even if the Trip Meter values were left as is, but they just added a "kWh In" register, that would be helpful.

We all pay for electricity based on the current at the meter, so yes there would be some losses in building wiring and the UMC, but I can assure you that these are vanishingly small in comparison to what we're talking about here. (In a typical town or city's electrical distribution system, the total system losses from transmission through distribution down through the local transformers and service wires is around 5%, and this even includes unmetered loads and theft of power on the system).

 

[schueppert]

Electricity companies reduce losses by using high voltages. Moving large amounts of power around at 240V results in losses that are certainly not "vanishingly small". For example, the 200' run from my meter to my garage results in losses of 4% when charging at 40A. I normally cut these losses in half by charging at 20A.

I agree that providing an easy way to measure vampire losses would be handy. It might even get Tesla focused on solving the problem! But I doubt they will do it because it just would focus on an issue of which many are blissfully unaware.

 

[jpasqua]

After charging for a few minutes (just testing something) I headed out to the store which is downhill from our house. I took the attached picture when I was initially surprised to see a negative number for wh/m. Makes perfect sense in this situation, but it was still surprising to see.

 

[schueppert]

1,066 miles, 332 Wh/mi, TX, 85, 19"

 

[FalconNinetyD]

Old average from April 1: mcornwell 351 4074 CA 85 21 1
New average from August 5: mcornwell 343 9575 CA 21 1

Reason for decrease in energy usage: Less test drives, longer commute/traffic on the freeway with new job/getting better at anticipating amount of regen required to stop...

 

[cschock]

Here's our data lifetime: S85, 19" wheels, 4701.3 miles, 1506.4 kWh, 320 Wh/m - Northern CA

It's going to go down a lot in the next few months, our garage door broke and we've been parking outside in 100+ degree heat for two months out of the four we've owned the car. The A/C load, especially for shorter around town trips was insane. I expect it to gravitate toward 310 Wh/m over time.

 

[AC1K]

Beautiful, Jerry; that's as flat as it can realistically get. My graph typically is so jagged that I can cut myself on it

at least your's isnt sawtooth

EDIT: crap the image was way too big

 

[mknox]

Electricity companies reduce losses by using high voltages. Moving large amounts of power around at 240V results in losses that are certainly not "vanishingly small". For example, the 200' run from my meter to my garage results in losses of 4% when charging at 40A. I normally cut these losses in half by charging at 20A.

I am involved in the distribution loss calculations for my utility. For our secondary metered customers, our distribution losses are 2.86% and this is the entire circuit including 27.6 kV feeders, distribution transformers and the 120/240 volt lines that feed homes and small businesses. (i.e. from the transmission system to your meter)

Since the Tesla Model S will maintain the current at your setting (20 amps or 40 amps or whatever you have set), I assume the losses you refer to are a reduction in voltage you're seeing at the car. 4% at 240 volts is nearly 10 volts which is excessive and if this is only occurring on the 200' circuit, I would suggest you have a problem. That would mean you're dissipating almost 400 watts of heat in your wiring!

Are you measuring voltage at your panel and at the car to verify this? If you simply see the voltage as reported by the car drop, then more likely you're seeing a voltage drop that goes right back to the utility distribution transformer. In this case, your meter would also be "seeing" a lower voltage and would therefore register lower watt-hours (meaning this wouldn't be costing you anything).

In the grand scheme, building wiring losses should be trivial.

 

[schueppert]

The NEC spec for #6 wiring (rated to 75A) is 0.49 Ohms per 1,000ft. A 200' run is actually 400' there and back so the total resistance is 0.2 Ohms. Put 40 amps through that and you get an 8V drop dissipating over 300W or about 4% losses depending on the voltage you started with. The NEC spec does cap voltage drop and hence losses at 5% - you need to move to thicker cable if you are going to go over that.

As I said, utilities keep losses low by using high voltages and a short drop from the transformer to the meter. Building wiring losses are not trivial. Have one of the utility guys explain it to you if your don't believe me!

 

[DFibRL8R]

60kWh, 19" wheels, Virginia. 9345miles, 2782kWh, 298Wh/mi.

Taking the car to Richmond International Raceway for Tesla event today so wanted to post before my numbers go up:biggrin:

 

[mknox]

The NEC spec for #6 wiring (rated to 75A) is 0.49 Ohms per 1,000ft. A 200' run is actually 400' there and back so the total resistance is 0.2 Ohms. Put 40 amps through that and you get an 8V drop dissipating over 300W or about 4% losses depending on the voltage you started with. The NEC spec does cap voltage drop and hence losses at 5% - you need to move to thicker cable if you are going to go over that.

Right. I missed the 200' run comment from before. My run is a bit under 50' and the voltage at my car is usually within a volt of what I see at the panel.

But my earlier point was that wiring losses are a small component of the overall difference between the 384 kWh the car's trip meter shows and the 495 kWh I actually put into the car.

If I charge at 40 amps/240 volts, that equals 9.6 kW. To put my 495 kWh in to the car at this rate would take about 52 hours over the month. Adding your 300 watts for building wiring losses, that would add another 16 kWh to the 111 or so kWh discrepancy I've reported.

Maybe not "vanishingly small" in your case, but still not a huge number. I think if it were me, I would have opted for a larger wire size for a run of that length, although you might never make up the difference in copper prices with the reduced wiring losses.

I still think using the kWhs at the charge port is the best way to look at how much the car is using. As we've demonstrated here, there are a lot of variables in building wiring between the meter and the outlet. To use an ICE analogy, a car's fuel consumption meter cannot account for any fuel that I might have spilled at the gas station, yet that spilled fuel would have gone through the pump and been paid for. These wiring losses are kind of like spilled fuel.

As I said, utilities keep losses low by using high voltages and a short drop from the transformer to the meter. Building wiring losses are not trivial. Have one of the utility guys explain it to you if your don't believe me!

No need. I've been a utility guy myself for 34 years. Typically, our concern ends at the meter (demarcation point) and we don't deal a lot with behind the meter building wiring :smile:

 

[schueppert]

With hindsight, I agree about using larger wire. Like most folks, I just went with code. I haven't done the math, but I suspect the payback on larger wire could be quite fast. This would especially be true for people installing the HPWC.

As others have noted, aren't the majority of the losses you are reporting from the vampire loss? This seems to average about 3kWh a day for me. I do believe Tesla will be able to significantly reduce this through firmware updates. The rest is internal battery losses, which I understand are around 8%. I believe the EPA mileage numbers assume total system losses of 16% (meter to drive train). Most of us are doing worse than that at the moment because of vampire losses, but I expect in the end all of us will do better.

 

[mknox]

As others have noted, aren't the majority of the losses you are reporting from the vampire loss? This seems to average about 3kWh a day for me. I do believe Tesla will be able to significantly reduce this through firmware updates. The rest is internal battery losses, which I understand are around 8%. I believe the EPA mileage numbers assume total system losses of 16% (meter to drive train). Most of us are doing worse than that at the moment because of vampire losses, but I expect in the end all of us will do better.

Over a two week or so vacation, my car came to life and topped up exactly 5 kWh every two days, so 2.5 kWh a day for me. Maybe it'll be a bit higher in winter. I'm noting a just under 30% discrepancy between the car's trip meter and my energy monitor data. So that would be vampire losses, internal battery losses and charger losses as far as I know.

 

[schueppert]

A quick correction to my earlier comment. I checked the EPA website here:

Electric Vehicles

and the actually assume 10% losses in the battery and 10% in the charger. So I would guess the losses you are seeing are roughly equally divided between the three loss types you mention.

 

[Cottonwood]

After charging for a few minutes (just testing something) I headed out to the store which is downhill from our house. I took the attached picture when I was initially surprised to see a negative number for wh/m. Makes perfect sense in this situation, but it was still surprising to see.

How is this for a first mile...

This is the everyday first mile down the hill from my house in Pagosa Springs, CO; I have no other way out of the property. I'll have to check, but it is something like 500 feet vertical down the hill in the first mile from my house.

 

[Jeff Miller]

Total Miles 664,052

Total Drivers 138

Summary

wh/mile
avg 343
median 341
stdev 38
dist_wt_avg 340

State / Province

State Wh N Miles
1 AB 300 2 610
2 AK 376 1 3285
3 AZ 329 6 20868
4 BC 336 3 20626
5 CA 339 39 195024
6 CO 354 4 14512
7 FL 320 5 34326
8 GA 312 3 27256
9 IL 362 14 38872
10 IN 354 3 15306
11 MA 364 2 6130
12 MD 368 1 21971
13 MI 331 1 2421
14 MN 338 6 23008
15 MO 292 2 15570
16 NC 315 2 9682
17 NJ 381 3 9239
18 NV 301 1 5000
19 NY 339 3 13059
20 OH 381 1 6028
21 ON 362 1 6208
22 OR 397 4 8230
23 PA 370 2 15149
24 QC 304 2 18100
25 TX 323 9 52810
26 UT 357 1 2015
27 VA 326 5 22508
28 WA 375 10 41180
29 WY 293 1 6659

Battery

Battery Wh N Miles stdev
1 40 306 3 4750 55
2 60 313 27 89372 24
3 85 351 99 512714 36

Wheels

Wheel Wh N Miles stdev
1 19 330 76 328745 37
2 21 359 42 217936 33

Battery and Wheels

Battery Wheels Wh N Miles stdev
1 40 19 274 2 4000 12
2 60 19 313 27 89372 24
3 85 19 341 46 230494 37
4 85 21 359 42 217936 33

Battery, State/Province, and Wheel

State Battery Wheels Wh N Miles
1 AB 60 19 296 1 235
2 AB 85 21 305 1 375
3 AK 85 19 376 1 3285
4 AZ 60 19 330 2 5980
5 AZ 85 19 309 1 4250
6 AZ 85 21 318 2 9888
7 BC 60 19 331 1 3386
8 BC 85 19 335 1 10040
9 CA 60 19 311 10 38674
10 CA 85 19 329 10 51054
11 CA 85 21 360 14 80712
12 CO 85 19 346 2 8900
13 CO 85 21 343 1 2765
14 FL 85 19 338 1 5165
15 FL 85 21 317 3 15176
16 GA 85 19 303 2 16256
17 IL 40 19 283 1 2000
18 IL 60 19 328 2 8790
19 IL 85 19 364 5 12420
20 IL 85 21 379 5 13862
21 IN 85 19 347 1 2881
22 IN 85 21 311 1 3425
23 MA 85 19 384 1 5230
24 MA 85 21 345 1 900
25 MD 85 21 368 1 21971
26 MI 60 19 331 1 2421
27 MN 60 19 309 3 4144
28 MN 85 19 358 1 12579
29 MN 85 21 373 2 6285
30 MO 40 19 266 1 2000
31 MO 85 19 318 1 13570
32 NC 85 19 266 1 2059
33 NC 85 21 364 1 7623
34 NJ 60 19 340 1 900
35 NJ 85 19 380 1 4739
36 NV 60 19 301 1 5000
37 NY 60 19 281 1 4297
38 NY 85 19 368 2 8762
39 OH 85 19 381 1 6028
40 ON 85 19 362 1 6208
41 OR 85 19 397 1 1565
42 OR 85 21 380 2 5979
43 PA 85 21 370 2 15149
44 QC 60 19 310 1 3000
45 TX 85 19 318 6 28017
46 TX 85 21 339 1 11793
47 UT 85 19 357 1 2015
48 VA 60 19 302 2 11345
49 VA 85 19 308 1 3144
50 VA 85 21 342 1 3600
51 WA 60 19 294 1 1200
52 WA 85 19 369 3 15668
53 WA 85 21 396 4 18433
54 WY 85 19 293 1 6659

Data

Wh Miles State Battery Wheels N LastUpdate
aaron.s 352 7000 NY 85 19 1 05/13/13
AC1K 305 375 AB 85 21 1 07/31/13
Al Sherman 311 3425 IN 85 21 1 08/02/13
AMN 345 1176 MN 85 21 1 07/22/13
Andrew Wolfe 333 4600 CA 85 21 1 05/13/13
AnOutsider 409 8567 PA 85 21 1 05/13/13
araxara 297 7969 AZ 85 21 1 06/07/13
Banahogg 310 4500 CA 60 19 1 06/11/13
bbmertz 348 2200 CA 85 NA 1 o
Beavis 343 2765 CO 85 21 1 o
Ben W 370 5000 CA 85 21 1 o
Bifff67 377 4419 VA NA NA 1 o
bigsmooth125 299 4000 TX 85 19 1 05/23/13
bob_p 326 3000 TX 85 NA 1 o
bosgig 345 900 MA 85 21 1 o
Brad-isa 365 1490 IL 60 19 1 o
brianman 386 12498 WA 85 21 1 07/16/13
BriansTesla 294 1200 WA 60 19 1 06/14/13
BryanW 357 2015 UT 85 19 1 06/09/13
Bucket22 387 1244 IL 85 21 1 o
captain_zap 385 4004 WA 85 21 1 o
Cattledog 348 6400 TX 85 19 1 o
ChadS 361 6000 WA 85 19 1 o
Chgd Up 353 8400 <NA> NA NA 1 o
ckessel 426 3000 OR 85 21 1 o
Cliff Hannel 345 4100 CA 85 19 1 o
cschock 320 4701 CA 85 19 1 08/05/13
Darmok 301 5000 NV 60 19 1 06/01/13
davecolene0606 310 13985 FL NA NA 1 06/15/13
David Trushin 378 1100 IL 85 19 1 o
DavidM 338 5165 FL 85 19 1 05/19/13
ddenboer 346 13000 CA 85 21 1 o
DfibRL8R 298 9345 VA 60 19 1 08/07/13
dfitz206 325 7901 WA 85 19 1 08/02/13
dflye 364 7623 NC 85 21 1 o
digitaltim 368 21971 MD 85 21 1 07/04/13
dlmorgan999 397 1565 OR 85 19 1 o
drbradfo 430 686 OR NA NA 1 o
drp 339 6100 IL 85 21 1 05/13/13
dtich 402 1300 CA 85 21 1 o
dwegmull 308 1800 CA 85 19 1 06/14/13
EarlyAdopter 415 1373 WA 85 21 1 o
eelton 404 1100 IL 85 19 1 o
efusco 318 13570 MO 85 19 1 07/25/13
ElSupreme 337 9000 GA 85 19 1 07/03/13
FlasherZ 403 1900 IL 85 21 1 o
fluxemag 369 750 AZ 40 NA 1 06/11/13
GeekGirls 316 6437 CA 85 19 1 05/13/13
gg_got_a_tesla 321 10021 CA 60 19 1 07/25/13
gregincal 325 3000 CA 85 19 1 07/12/13
gtimbers 330 900 CA 85 19 1 o
HTK 335 10040 BC 85 19 1 07/28/13
huntjo 380 2847 CO NA NA 1 o
ibcs 381 6028 OH 85 19 1 o
IlliniT 291 7300 IL 60 19 1 06/07/13
Iz 281 4297 NY 60 19 1 07/31/13
J in MN 278 1724 MN 60 19 1 07/31/13
Jason 339 11793 TX 85 21 1 05/13/13
Jason S 351 4334 CA 85 NA 1 o
jchangyy 323 1800 CA 85 19 1 o
Jeff Miller 321 1968 IL 85 19 1 07/04/13
jeffnorman 357 1118 IL 85 21 1 07/28/13
jerry33 258 7651 TX 85 19 1 08/01/13
jhs_7645 399 558 WA 85 21 1 o
jive_devil 300 2500 CA 60 19 1 06/16/13
jjaeger 363 3974 CA 85 19 1 o
johndoe74 309 4250 AZ 85 19 1 06/08/13
johngray 391 4879 WA NA 19 1 o
jomo25 315 4480 AZ 60 19 1 08/02/13
jpasqua 290 2216 CA 60 19 1 06/02/13
jweinstein 376 3285 AK 85 19 1 05/26/13
kaivball 340 1400 CA 85 21 1 o
kcveins 355 5552 IL 85 19 1 05/13/13
Kipernicus 320 2185 CA 60 19 1 o
Kklabunde 347 2881 IN 85 19 1 o
Klaus Fechner 323 1122 CA 60 19 1 06/25/13
kvietor 301 9076 FL 85 21 1 o
lholtzman 364 2700 IL 85 19 1 o
Lloyd 354 6467 CA 85 21 1 05/13/13
lolachampcar 311 4500 FL 85 21 1 06/15/13
mark 391 1700 TX 85 19 1 o
MassAmped 384 5230 MA 85 19 1 06/15/13
matthew.johnson 407 3500 IL 85 21 1 o
mckemie 279 7200 TX 85 19 1 06/30/13
mcornwell 343 9575 CA 85 21 1 08/05/13
meduri 330 11000 GA NA NA 1 o
Michael S 290 3915 CA 60 19 1 o
MitchL 383 3300 CA 85 21 1 o
mnx 362 6208 ON 85 19 1 07/26/13
Model S P 338 1919 AZ 85 21 1 05/23/13
Mossisthecat 331 3386 BC 60 19 1 07/12/13
Nathan Smith 331 6582 PA 85 21 1 06/01/13
neroden 383 1762 NY 85 19 1 05/13/13
Nickjhowe 340 1600 FL 85 21 1 o
NJS1207 424 3600 NJ 85 NA 1 o
ohaq 331 2421 MI 60 19 1 06/30/13
pbrulott 310 3000 QC 60 19 1 06/11/13
pilotSteve 422 1767 WA 85 19 1 o
Psullivan 333 7885 CA 85 21 1 05/13/13
qphan79 292 4740 CA 60 19 1 o
raptorweb 401 5109 MN 85 21 1 o
rcc 365 3500 CA 85 NA 1 o
rlcordeiro 358 6600 CA 85 NA 1 o
rpavlicek 326 6421 CA 60 19 1 07/12/13
Sacrament055 283 2000 IL 40 19 1 06/15/13
scaesare 308 3144 VA 85 19 1 07/01/13
schueppert 332 1066 TX 85 19 1 08/05/13
SCW-Greg 334 2979 OR 85 21 1 08/01/13
smd 369 7950 CA 85 NA 1 05/13/13
Sparrow 269 7256 GA 85 19 1 07/31/13
spatterso911 354 2000 CA 85 21 1 o
StephRob1 387 4938 CA 85 21 1 o
StephRob2 336 1054 CA 60 19 1 o
stevezzz 326 8900 CO 85 19 1 06/15/13
sublimaze1 339 10000 TX NA NA 1 07/12/13
SuperCoug 368 1000 WA NA NA 1 o
svoelpel 266 2059 NC 85 19 1 07/05/13
tdiggity 345 760 CA 85 21 1 o
tesla2012 346 1500 AZ 60 19 1 06/11/13
tezco 366 NA CO 85 19 1 o
Tomanik 296 235 AB 60 19 1 05/18/13
Tommy 325 18134 CA 85 19 1 06/08/13
Toto_48313 299 15100 QC 85 NA 1 08/01/13
Treker56 305 2000 VA 60 19 1 06/30/13
Vern110 407 1800 IL 85 NA 1 o
Vexar 367 1015 MN 60 19 1 o
Vger 342 7200 BC 85 NA 1 06/07/13
William13 403 9000 IN 85 NA 1 05/13/13
wraithnot 339 6208 CA 85 19 1 05/12/13
wycolo 293 6659 WY 85 19 1 06/15/13
XK8driver 342 3600 VA 85 21 1 o
xray 371 10131 CA 85 21 1 07/25/13
yobigd20 380 4739 NJ 85 19 1 o
youlikeadajuice 340 900 NJ 60 19 1 o
zdre 266 2000 MO 40 19 1 07/26/13
Zextraterrestrial 373 10356 CA 85 21 1 06/07/13
Zythryn1 358 12579 MN 85 19 1 06/25/13
Zythryn2 282 1405 MN 60 19 1 06/25/13

wh.m.deciles
0% 258
10% 294
20% 309
30% 323
40% 333
50% 341
60% 351
70% 364
80% 378
90% 398
100% 430

 

[Denarius]

first time posting, hopefully I don't miss anything.

85kWh, 21" wheels, Utah, 4399.7 miles, 1392.7kWh, 317Wh/mi.

 

[Cottonwood]

Another first post:

85kWh, 21" summer, 19" winter wheels, probably 75% or so summer 21" wheels, Colorado, 6222.2 mi, 2084.8 kWh, 335 Wh/mi