Love my Tesla, but almost got stranded because of way out of whack mileage estimate

carrerascott · Mar 18, 2014

Took my first road trip using a Supercharger this weekend. From Charlottesville to Greensboro NC for the ACC Tournament. Did a full range charge (254miles) and headed down on Thursday, a pretty cold day (upper 30s) and headed straight to the Burlington NC supercharger, about 199 miles. I didn't drive fast, did some hypermiling (putting in N down long hills), and got there with about 20 miles to spare. So got about 219 miles on the 254 mile estimate. Charged there and headed to Greensboro to watch my Hoos roll through the ACC tournament.

On Sunday after the tournament, we headed from Greenbsoro to Burlington, plugged in and went and had something to eat. Temps were dropping and slight drizzle falling. Got charged up to 252 miles, and headed out on the 199 mile trip. Did the same thing, drove slowly (55-60), hypermiling when I could, had to have some defrosting on because everything fogged up without it. Wipers running. I noticed we were losing miles fast --after 80 miles of driving, we had used about 120 miles of range, so we were down to 132 left with 119 to go. I kept doing my best but eventually we were in the negative -- when we had about 75 miles to go, we were down to 70 miles of charge. Weather was getting nasty, snow on the roads, cold (32) and moderately windy. We pulled up Chargepoint and there was nothing anywhere near us. I calculated what we were losing in my head and figured we could make it to the Hyatt Place in Charlottesville that has chargers with a few miles to spare (about 20 miles from our destination). Fortunately we did make it there with 5 miles of charge left, and 20 miles to home. We plugged in, went to a nearby restaurant and had a couple drinks, and came back to 40 miles of charge and headed home.

I was pretty disappointed though that 250 miles of charge would only get me about 180 miles. And this was not driving fast. Yes it was cold (32) and snowy, but that's a lot of mileage loss...

I still love my Tesla.

Zextraterrestrial · Mar 18, 2014

how windy was it?

that might have been the big killer, + the 32F temp and snow, but wind is worse

ckessel · Mar 18, 2014

carrerascott said:
I was pretty disappointed though that 250 miles of charge would only get me about 180 miles. And this was not driving fast. Yes it was cold (32) and snowy, but that's a lot of mileage loss...

Yep, that's pretty much my experience. There was a thread at one point estimating the impact of a bunch of the unfavorable variables and came up with a 2/3rd rule of thumb. As in, you'll only get 2/3rds of the rated range at freeway speed when it's cold and wet. Which is 60% of the year in Oregon...

carrerascott · Mar 18, 2014

I was driving 55 on 65-70mph limit roads. I can only imagine how much worse it would have been if I had driven faster (before it got really snowy).

It was windy but not crazy windy. That's not exactly a scientific statement though.

Jeffruby · Mar 18, 2014

what battery do you have?

ElSupreme · Mar 18, 2014

I was driving to Florence, SC over Thanksgiving. And had a 250 mile jump to Columbia before I would charge again(I had a backup charge point in Augusta). The whole trip it was 34-40F and raining. Even with a loss of 1000 ft I still had to drive 50 mph to keep myself in the black for about 60% of the leg. I was negative 2 miles for most of it, but getting close to Columbia it flattens out, and I was able to end with 1 mile indicated left.

I noticed a difference between 55 and 50 that over the whole pack would probably be 20-30 miles.

But even doing 50 seemed a bit dangerous in parts on the interstate.

swegman · Mar 18, 2014

I drove from DC to FL in November and experienced similar range issues. On a full range charge (254 miles to start), I would only get about 210 actual driving miles, driving 55-60 mph in 70/75 mph zones, with HVAC OFF. I have the 21 inch tires and I note you have them too (unless you changed them for the winter). Tesla tells me the mileage hit is from the Michelin Pilot tires on the 21 inch rims, though many people here on this website dispute that assertion. I tend to believe Tesla.

Zextraterrestrial · Mar 18, 2014

carrerascott said:
I was driving 55 on 65-70mph limit roads. I can only imagine how much worse it would have been if I had driven faster (before it got really snowy).

It was windy but not crazy windy. That's not exactly a scientific statement though.

driving in mild cold/snow (20-30F) I'd plan on using ~400Whr/mi to be safe which is something like 180-190mi.
my SC charging goal was to get 30% extra range than distance for CA I-5 driving and this worked perfect so 200mi rated will get me 140mi driving faaaast. or slower w/ bad weather.

ElSupreme · Mar 18, 2014

Oh and I had my heat in 'range mode'. It was about 66-68 in the car the whole trip. And I only used the blower (with AC) to defog the windows. No heat! I did do one heated defog to clear some fogged windows, but was vigilant about keeping it clear just blowing from then on.

When I put the heat on it was apparent that I wouldn't make 250 miles.

I did not do any wild 'hypermile' techniques with neutral or anything. I was about 80% cruise control. But manually did the speed over rolling hills (to limit regen) where I would roll the downhill, then maintain ~20kW uphill until I was at 50mph, then I would maintain 50mph.

carrerascott · Mar 18, 2014

Don't know how to check. P85, vin 6040

Jeffruby said:
what battery do you have?

notailpipe2112 · Mar 18, 2014

I just got back from a roadtrip from Toronto to NYC last week and I was freshly reminded that a) cold is a killer b) rain/snow kills rolling resistance but when it comes to the Tesla (and any car I bet)....IT IS ALL ABOUT THE WIND. I did a stretch from Albany to the Darrien supercharger first going down, then back up a few days later, and conditions were identical for trips except for wind and the difference was considerable in terms of range loss. I have seen this before on other longer winter trips, but this was a fresh reminder. My point here is basically that wind has a major effect, and I've been reminded to not just check temperature before I leave on a trip, but wind speed.

mgemmell · Mar 18, 2014

There are many variables to take into account such as tire pressure and car load, but frankly the figures just don't jive with my experience. I also have a P85 (P85+ actually).

We have gone 5 up (3 young adult kids and us two) plus all our ski gear in sub-zero weather with snow and wind, and we have done better than this. We have managed 400kms (250miles) on a single charge with range to spare. Sure, you have to drive easy but 90km/h should do it.

It sounds like you didn't charge to 100%? Am I wrong? Sure, it's not strictly necessary but every time I do a long drive I like to charge it to the max.

In previous posts related to our long drives (Holland to Spain, Spain to the Alps and back, Madrid to Barcelona, Madrid to Valencia etc) I have also mentioned that I suspect wind could be a decisive factor.... a 10km/h head wind can knock 10% off your range. I recall suggesting that a really cool navigation app would take into account prevailing wind patterns when estimating energy use and expected range.

I need to write a good detailed blog entry on my site about these things but one thing I can definitely say is that heating etc. has such as small impact on range it is just not worth suffering int he cold. You'll save more energy if you just drop your speed by 1mph!

Stoneymonster · Mar 18, 2014

Just curious, do we think this situation is worse than with an ICE vehicle? Or do we just not notice in that case because fuel is ubiquitous?

Zextraterrestrial · Mar 18, 2014

'new' noaa wind map

http://preview.weather.gov/graphical/?zoom=5&lat=38.33054&lon=-117.93433&layers=00BTFFTT&region=0&element=0&mxmz=false

but you need to select the wind tab

carrerascott · Mar 18, 2014

Charged to 100%. Our car has 21,000 miles on it and current max range charge is about 152-154 miles.

mgemmell said:
There are many variables to take into account such as tire pressure and car load, but frankly the figures just don't jive with my experience. I also have a P85 (P85+ actually).

We have gone 5 up (3 young adult kids and us two) plus all our ski gear in sub-zero weather with snow and wind, and we have done better than this. We have managed 400kms (250miles) on a single charge with range to spare. Sure, you have to drive easy but 90km/h should do it.

It sounds like you didn't charge to 100%? Am I wrong? Sure, it's not strictly necessary but every time I do a long drive I like to charge it to the max.

In previous posts related to our long drives (Holland to Spain, Spain to the Alps and back, Madrid to Barcelona, Madrid to Valencia etc) I have also mentioned that I suspect wind could be a decisive factor.... a 10km/h head wind can knock 10% off your range. I recall suggesting that a really cool navigation app would take into account prevailing wind patterns when estimating energy use and expected range.

I need to write a good detailed blog entry on my site about these things but one thing I can definitely say is that heating etc. has such as small impact on range it is just not worth suffering int he cold. You'll save more energy if you just drop your speed by 1mph!

ElSupreme · Mar 18, 2014

Stoneymonster said:
Just curious, do we think this situation is worse than with an ICE vehicle? Or do we just not notice in that case because fuel is ubiquitous?

My mother-in-law was in town this past weekend. She has a new Subaru, and is keeping track of the mileage in detail. She commented on 20%+ hits in the cold.

It is just more noticeable in the Model S because we have the numbers in our face all the time, and range is a 'more apparent' issue, due to the anxiety of refilling.

carrerascott · Mar 18, 2014

Stoneymonster said:
Just curious, do we think this situation is worse than with an ICE vehicle? Or do we just not notice in that case because fuel is ubiquitous?

I'm sure you get less MPG in an ICE car but like you said, there are filling stations everywhere, and it takes 2 minutes. So it's not an issue...

NigelM · Mar 18, 2014

I'm always surprised by headlines like this one. I recognize that this might sound pedantic but the mileage estimate wasn't "out of whack"...what happened was the car can't account for changes in the weather but this is where we as human beings need to take responsibility. Tip of the hat to Scott that he did have the sense to find a charging spot and plug in.

When the trip planning function arrives with v6.0 I understand it will take account of ambient weather conditions but I do hope that owners will still realize that changing weather conditions can rapidly impact range.

carrerascott · Mar 18, 2014

Still, when buyers of the "affordable" tesla in a few years experience this (if they do) it will make a lot of negative headlines, IMHO. Unless there are a lot more charging stations, there will be a lot of stranded motorists.

Lloyd · Mar 18, 2014

My rule of thumb is to expect -10% from rated range for any heavy heating or air conditioning, -5% for a headwind > 30 mph, -20% for constant speed 75 mph, -2% rain.

Love my Tesla, but almost got stranded because of way out of whack mileage estimate

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