Testing Distance Limits

Testing Distance Limits

This weekend we took our 85Kwh Model S from Austin to Plano and back. We maxed out the charge, left Friday night around 7:30PM to avoid all traffic. Arrived in Plano with a 42mile residual tank, and a very slight mileage degradation of about 8 miles - by mileage degradation, I mean that our stated max range was 270 when we left, and if you added up all that we drove + what was left, it totaled 262.

The return was not quite as successful, we lost about 20 miles - and decided to have dinner at the Domain in Austin which also happens to have the Tesla showroom and charging stations. We still cant' exactly pin point the exact cause of mileage degradation - either the heat or wind resistance. Overall, for the life of the car, we average about 350wh/mi; for the trip we ranged between 280 - 322; meaning we were driving a hell of a lot more efficiently than we normally do. We left at 2PM in the afternoon, so the heat was at its max.

Other notable variables - car had 5 passengers, 3 adults and 2 children (and a dog). The trunk was full, frunk rather empty. We operated in range mode both ways, except for the first 45mins of the return trip (can't imagine this caused that drastic of a difference). Best part of the whole trip, is that we charged the battery 3 times on the trip (once when we arrived, once the next night, and for a brief period at the Domain), and we didn't have to pay for any of it. Austin Energy has a great program with Charge Point networks. End to end, transportation to Plano from Austin cost us $10.20 at our current Kwh rate from Austin Energy for the initial outbound charge.

My wife and I took the challenge, and the Tesla passed with flying colors. Have to admit, WACO super charging stations would have been nice, but we were 2 days too early!

nickjhowe | September 8, 2013


earlyretirement | September 8, 2013

Thanks so much for taking the time to post this. I find posts like this really valuable. I'm taking my first longer distance trip (vs. daily use). I'm driving from San Diego to Los Angeles and back in the same day so I'll see how my numbers stack up.

I'm planning to leave early in the morning, go to a business meeting, go to lunch then hit the Tesla Supercharger in Hawthorne then drive back home the same day.

Tâm | September 8, 2013

Speed eats up your miles real quickly, so slow down if you want more range.

Wind also eats up your miles just as bad as speed depending on how bad the wind is. It's good to plan to charge extra miles in case you might encounter strong headwind.

Outside heat is not as bad as cold winter. A/C does eats up your miles but not as bad as speed and it uses less energy than heater does.

Stop and go also eats up your miles.

diegoPasadena | September 8, 2013

As others have stated, wind is most likely the variable you encountered. Going 70 mph with a 15mph headwind takes pretty much the same energy as going 85 mph.
It's a bit tricky, because we can rarely detect 15 mph winds.
This map has been posted before, I think:
It shows prevailing wind directions and speed. Currently, for example, it shows about a 6 mph wind from the south helping you to get from Austin to Plano. If the conditions were the same when you drove, that's most of your explanation right there.

Brian H | September 9, 2013

Rapid changes in speed are almost the worst. Gently, gently. ;)

raguis | September 9, 2013

Thanks everybody for the responses. We too believe wind is the culprit. We were pretty diligent about limiting hard accelerations, or going to fast. For the first time in our lives, we were usually 2-3mph below the speed limit. Between Austin and Plano the limits span between 60 - 75mph, with the majority of the trip right around 70. We generally stayed around 68-73. For sure, once we crossed 70mph, the degradation was much more pronounced.

We've become a pretty green family, so our next trip to Plano will be in our Jetta Diesel wagon. Our goal is one tank for the round trip - which should be eminently doable.

Anonymous | September 9, 2013

earlyretirement, that's not going to be a challenge (with recharging), I'm wondering about up/back with no recharging. I think it should be possible (with the 85).

Either way, please post your mileage results.

jai9001 | September 9, 2013

My experience is that extreme heat, generally above 90 degrees, eats up range.

The past 2 weeks the average temperate has been above 90 in Memphis and I can barely average below 350 kWh/mile driving like a grandma.

Curious if others have the same experience.

Also curious how much humidity affects battery efficiency.

welockett | September 9, 2013

I am not so sure how effectice "range" mode is. I have done two identical trips (route, distance, speed, temps, etc) and I noted the "range" mode to be less efficient than the standard mode.

Standard mode:

Rated range at start: 240 miles
Rated range at end: 48 miles

Range mode:

Rated range at start: 250 miles
Rated range at end: 38 miles

jat | September 9, 2013

@welockett - you aren't controlling for all the variables then -- all range mode does is limit the power that can go to the HVAC system.

gooshjkc | September 9, 2013

Like many, I appreciate posts like this. I know the Model S can make long distance trips, but for my family and I we don't have the patience as many do (eating wise and driving at a slow pace - meaning I have to be passing everyone on the road). That's why we are planning to keep couple of our ICE cars for long trips.

mikefa | September 9, 2013

i think you and the MS did pretty good considering a fully loaded car.

markapeterman | September 9, 2013

FYI - Waco Supercharger was functional as of Saturday

raguis | September 9, 2013

@markapeterman - not so, or not so per Tesla. Although we had enough range on Sunday to make it to the Tesla showroom in Austin where we charged up while eating dinner, we figured, why not cal Tesla, play the distressed card, and see if they would let us in to Waco secretly lest our battery die en route. They sadly conveyed that the station wasn't open yet, and they were even afraid to route us to a nearby charging station for fear that we might die whilst looking for it. I admit our motive and approach wasn't the purist, but we were rebuffed anyway.

Brian H | September 11, 2013


Call them and tell them you died looking for the station, and your estate's lawyer will be in touch.

BillPlanoTexas | September 12, 2013

I called tesla to confirm Waco was open the day before ribbon cutting and they said it was. charged with no problems.

nolancn | September 12, 2013

This summer I have made the 273 mile trip from Macon GA to Charleston SC half a dozen times under ideal conditions (80 - 90 degrees F, no significant wind, AC set @ 74 degrees F, 19 inch wheels, cruise set @ 62 mph, 2-4 passengers, modest amount of luggage). Beginning rated range usually 270 or 269 miles with ending range of 9 - 11 rated miles. Energy meter shows rather consistently 286-289 watts per mile. Generally this is a fairly flat route with gently rolling hills for about 100 miles. One trip was made with cruise set @ 55 and average watts per mile was 262 for the trip. Hope this helps. Also I am eagerly awaiting a supercharger on I-95 near Savannah (supercharger map seems to indicate one to be placed this fall.

bonaire | September 12, 2013

Elevation change can play a visible increase or decrease in range.
But Plano/Austin are roughly the same elevation.