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An update: 23,419 miles; 313 Wh/mi lifetime. That's two winters and a summer of driving, all on OEM 19" Goodyear all-seasons except for this winter, on Michelin Xi3's).
I get my Goodyears back on tomorrow. Will see if I can get the Wh/mi average down even lower this summer.
I get my Goodyears back on tomorrow. Will see if I can get the Wh/mi average down even lower this summer.
dirkhh
Middle-aged Member
Uhh, look at these numbers. What is striking is the two biggest outliers for OR:
dlmorgan999 397 1565 1
drbradfo 430 686 1
look at the low mileage they are reporting. Would it make sense to do weighted averages by miles driven instead of same weight to every person? That would drop Oregon down to 353 (instead of 367).
(and oh, wow... I have the lowest number in OR...)
You are right - outliers like these do affect the mean, but not the median, which, in the case of OR isn't so far from the mean. But the real problem, as you pointed out earlier, is that we only have eight data points for OR, and some of those have low mileage. To make firm conclusions, we need more data. The distance weighted mean is a good idea. I report it as a separate line in the overall summary where it is close to the mean and median. My only hesitation in making this the sole measure is that it almost certainly gives a lot of weight to highway miles vs city miles. But I can easily display all three measures (mean, median, distance weighted mean) in different columns, so I'll do that on the next update.
Here's a quick look at the current data using distance weighted averages. OR and WA are still on the high end...
State Distance_wt_wh/mile
1 AB 318
2 AK 322
3 AZ 305
4 BC 337
5 CA 330
6 CO 333
7 CT 330
8 ESTONIA 396
9 FL 318
10 GA 313
11 HI 315
12 IL 343
13 IN 351
14 MA 334
15 MD 347
16 MI 347
17 MN 347
18 MO 317
19 NC 343
20 NETHERLANDS 409
21 NH 279
22 NJ 363
23 NV 301
24 NY 336
25 OH 381
26 ON 352
27 OR 353
28 PA 354
29 QC 300
30 TX 317
31 UT 331
32 VA 304
33 WA 360
34 WI 303
35 WY 293
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Look at it this way:
Tread width 220 mm
Water depth: 3 mm
Distance: 1 km
Assumption: The rear tires are exactly behind the front tires at all times.
2 tires X 220 mm tread width X 3 mm water depth X 1,000,000 mm distance = 660,000,000 mm[SUP]3[/SUP] = 0.66 m[SUP]3[/SUP] displaced water volume.
1 m[SUP]3[/SUP] of water weighs 1000 kg.
So for each kilometre driven, your pushing 660 kg of water.
Great Dane
Member
Thank you mknox for the explanation of power measurement
I am happy to see you are using lower amps to charge the car
there are less heat losses every where when you do that
I also charge at lower rates ( 15- 20 amps )
also less strain on all the power plugs and connections and charger inside the car
I am happy to see you are using lower amps to charge the car
there are less heat losses every where when you do that
I also charge at lower rates ( 15- 20 amps )
also less strain on all the power plugs and connections and charger inside the car
Understand. It's a lot of water. We all assume that that requires a lot of energy to do.
My question is: How much energy does that require? Even just ballpark, so we can guess a number of Wh/km vs. Wh/mi to add to our average energy use.
From the Vehicle Energy Use Simulator App:
No wind or water and 55 mph 12.50 kW being used 2.11 kW being wasted
No wind or water and 65 mph 17.02 kW being used 2.45 kW being wasted
No wind, light rain 55 mph 14.46 kW being used 2.44 kW being wasted
No wind, light rain 65 mph 19.29 kW being used 2.78 kW being wasted
No wind, medium rain 55 mph 15.48 kW being used 2.61 kW being wasted
No wind, medium rain 65 mph 20.47 kW being used 2.95 kW being wasted
No wind, heavy rain 55 mph 16.36 kW being used 2.76 kW being wasted
No wind, heavy rain 65 mph 21.49 kW being used 3.10 kW being wasted
Comparing dry to heavy rain:
So at 55 mph 31% more energy is used. (16.36+2.76)/(12.50+2.11)
At 65 mph 26% more energy is used. (21.49+3.10)/(17.02+2.45)
The non-obvious result is because the rain is close to being a constant while aerodynamic resistance increases.
kvietor
Model S VIN 168
Great thanks! I presume that's referring to steady state power at constant speed and listed environmental conditions.
I'm sorry to say, but I have trouble trusting a "simulator app" where they reference "energy used" with the unit of kW. Who knows what else the author messed up internally. But it looks cool and convincing :biggrin:
I'm sorry to say, but I have trouble trusting a "simulator app" where they reference "energy used" with the unit of kW. Who knows what else the author messed up internally. But it looks cool and convincing :biggrin:
This is Wayne Brown's second simulator app. The previous one was tested extensively by Prius forum members and was shown to be accurate (at least within the ability of the Prius owners to measure accuracy).
(Steve's been after me to get that NA out of the Colorado lineup.) Steve--you're running circles around me (but you did have a couple of month's head start). I've only got 2193 mi, 332 wH lifetime. 19's in winter and 21's summer. Of course, I've put 12,000 on the Leaf just going back and forth to the office (no parking the Tesla in that dingy parking lot)...
B>
It is. Charging at 120V is particulary inefficient since all the cooling pumps and electronics have to run for a longer period of time and their energy consumption represents a higher percentage of the total energy coming out of the wall. There is less heat produced at any one instant with lower amps, but since charging takes so much longer, the total heat produced is greater. Also, a longer charging time means that the battery has to be kept at the proper temperature for charging for a longer period of time.
SCW-Greg
Active Member
March numbers, S85 on 21s
1780.4 mi, 636.3 kWh, 357 Wh/mi
Last couple of drives, no HVAC needed, avg coming down to 280 with 60 mi round trip PDX rush hour commutes.
1780.4 mi, 636.3 kWh, 357 Wh/mi
Last couple of drives, no HVAC needed, avg coming down to 280 with 60 mi round trip PDX rush hour commutes.
actually that's not true. The losses are the same. The resistance in the cable doesn't change with Ampere. Charging at half the current (Ampere) you have lower loss, but you need to charge twice as long. The loss in percent is exactly the same at the end.
The AC charger in the car is optimized for higher Amps so it's actually less efficient at lower Amps.
You can see that on Tesla's own website when you look at the different charging methods Tesla Charging | Tesla Motors
The lower the charge rate, the higher the total amount of energy needed to recharge the battery.
The wires in the car are designed to handle more than 400 Volt and at least 320 Ampere. No need to worry about charging at 240 Volt and 40 Amp.
mnx
2018 M3P
I took off my winter tires on March 18th and this is what the car had:
Summary:
23,839km total driving, 239Wh/km overall average.
On Winter tires this winter: 6615km, 284Wh/km (It was COLD, and I don't commute and have a lot of short trips...)
overall converted to Wh/mi and in the correct format:
mnx 18/03/2014 382 14780 ON P85 19" (winter and summer tires)
Summary:
23,839km total driving, 239Wh/km overall average.
On Winter tires this winter: 6615km, 284Wh/km (It was COLD, and I don't commute and have a lot of short trips...)
overall converted to Wh/mi and in the correct format:
mnx 18/03/2014 382 14780 ON P85 19" (winter and summer tires)
Incorrect -- the Joule-heating law is P=(I^2)*R, so with higher current there is higher loss across the cable for a given total charge quantity, because it's not a linear equation. Just as a theoretical exercise, let's say that resistance is 1 Ohm, so let's drop the R. 1 hour at 40 amps = 1.6 kWh lost (1600W * 1 hour), 2 hours at 20 amps = 0.8 kWh lost (400W * 2 hours). So while you charged for twice as long, you lost 1/2 the amount across the cable.
That said, I think I calculated it to ~100W at 80A at one point across my circuit. Running the same setup at half the amps will basically half the loss across the cable for a straight doubling of charge time, so 100W loss for 1 hour vs. 25W loss for 2 hours. Having to run pack heaters and monitoring electronics and keeping everything awake for that extra hour can tend to offset the difference quite easily, and as a result this is why the higher charging current tends to work out in the end.
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