Regen and efficiency in the mountains

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PNWmisty

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Aug 19, 2017
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Anacortes, WA
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#1
I was pretty impressed with the Model 3 efficiency in the mountains today. I just returned from a 47.7 mile round trip with a starting elevation of 890 feet and a maximum elevation of 5069 feet. My consumption for the round trip was only 170.8 Wh/mile. The road is twisty and steep in places so speeds were slow, mostly 40 mph and less with a couple of exceptions. This means I only used 36 miles of range to travel 47.7 miles! A map of my route from Glacier, WA to Artist Point:
https://goo.gl/maps/M8cDHdYSArE2

I consumed 10,920 Wh during the 24-mile leg to the top (455 Wh/mile) but gained 2,773 Wh on the 23.7-mile return (-117 Wh/mile). The legs are different lengths because the highway splits into two one-way sections for about a mile and one side is longer than the other).

This was a little better efficiency than a similar trip (slightly shorter trip with less total elevation gain/loss) I reported on last month. Speeds were slower for this trip which is what I attribute the better overall efficiency to (170.8 Wh/mile). Overall consumption was 8,147 Wh and taking into account 10% for charger losses means it took 8,962 Wh total for the 47.7 miles. I pay $0.098/kWh for the first 600 kWh and $0.118/kW for all consumption above 600 kWh. So, at the highest electrical rate of $0.118/kWh, my electrical usage on this trip was $1.06 or $0.022 per mile. My Volvo would get about 24 mpg on the same trip and would consume 1.99 gallons of premium @ the current price of $3.49/gallon or $6.94 for the same trip. That's $0.145/mile vs. $0.022/mile. Which is 6 1/2 times as much for the gas vs. the electricity (not even adding in the cost of an oil change every 5,000 miles which adds another 1.6 cents/mile based on an $80 bill for oil, filter and labor). That means the electricity is not much more per mile than the cost per mile of oil changes!
 

Bernard

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Aug 3, 2017
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Hawaii, HI
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#2
I mentioned in another forum that I took a round trip (in Hawaii) that entailed going from sea level up to 6700ft and down to sea level and the same again to come back, plus some additional ups and downs, for a total of over 18'000ft of climbing (and the same of descent, as as I returned to my starting point), with all of the climbing between 3000ft and 6700ft on cruise control at 60-65mph. I started with 311mi range and arrived after 235mi of driving with 70mi range remaining, so regen did an amazing job. (I'd need a lot more data points to be sure, but it looks like regen was good enough to get efficiency on a trip that was almost all up and down to the same level as observed on trips on flat ground.)

Worth noting: AC was running on med-high for the entire trip (it was 90F outside for much of the trip, had AC set to 75F), except over the section over 4500ft, and my observation is that running the AC at that level takes about 25% of the total energy. Thus the range in nice fall weather in the mountains in the continental US (no AC, no heating) should be over 350mi on a full charge, even with lots of climbing. Tesla is, as usual, conservative with its estimates.
 

tivoboy

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Mar 24, 2017
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Palo Alto, CA
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#3
I mentioned in another forum that I took a round trip (in Hawaii) that entailed going from sea level up to 6700ft and down to sea level and the same again to come back, plus some additional ups and downs, for a total of over 18'000ft of climbing (and the same of descent, as as I returned to my starting point), with all of the climbing between 3000ft and 6700ft on cruise control at 60-65mph. I started with 311mi range and arrived after 235mi of driving with 70mi range remaining, so regen did an amazing job. (I'd need a lot more data points to be sure, but it looks like regen was good enough to get efficiency on a trip that was almost all up and down to the same level as observed on trips on flat ground.)

Worth noting: AC was running on med-high for the entire trip (it was 90F outside for much of the trip, had AC set to 75F), except over the section over 4500ft, and my observation is that running the AC at that level takes about 25% of the total energy. Thus the range in nice fall weather in the mountains in the continental US (no AC, no heating) should be over 350mi on a full charge, even with lots of climbing. Tesla is, as usual, conservative with its estimates.
Nice. If you plot the route and conditions into the evtripplanner, what does it show you as results for the same trip?
 

Reid

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Apr 25, 2018
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Redwood City, CA
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Model 3
#4
Low speeds = high efficiency. You'd almost certainly beat EPA estimates doing this even on an ICE. You'll really only do worse than flat road if you have a net uphill.
 

Reid

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Apr 25, 2018
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Redwood City, CA
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#6
ICEs can't regen on the downhill ;)
That's why I said "even on an ICE".

I do roadtrips over 8000' all the time. My best-ever mileage on my Golf was on a ski trip where I climbed over 10,000ft but the net was 0 as I returned home to sea level, and I'm not exactly polite with the throttle in the hills. I find the only vehicles that really suffer on hilly terrain are very underpowered to begin with.

Obviously with the regen, a hybrid or electric will fare even better.
 

PNWmisty

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Aug 19, 2017
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Anacortes, WA
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#7
Nice. If you plot the route and conditions into the evtripplanner, what does it show you as results for the same trip?
Apologies for the late reply but I just noticed this while browsing old threads.

I plugged the relevant info into evtripplanner.com using the following data:

Speed multiplier: 1.1 (chosen so the estimated driving time matched the actual driving time)
Payload: 350 lbs. (actual payload)
Wind: 0 (the actual wind was very light and variable)
External/Cabin Temp: same (70 degrees)

Here are the results:

Driving distances matched recorded distances exactly.

ETT estimated uphill leg: 431 Wh/mile
ETT estimated down leg: -117Wh/mile
ETT estimated round trip: 157 Wh/mile

Actual uphill: 455 Wh/mile
Actual Down: -117 Wh/mile
Actual round trip: 170 Wh/mile

The accuracy of the EV Trip Planner is impressive (at least in this particular scenario)!
 
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