Sunday 19th May. Palm Desert to Corning, CA. Encountered significant headwinds (20 to 40 mph) which decreased range by about 10-15% (e.g. from Harris Ranch charged to 251 and made it to Folsom by 20 miles rated range remaining with speed at 55 mph. Drafted trucks and used cruise control but it was close. Range anxiety exists. Using a 78% of rated range to get to your destination allowing for 7.5 miles for 1000 feet of elevation seems from this trip so far to be ok, but not if you encounter significant headwinds. Off to Seattle in the a.m. and will keep my log and report.

Hogfighter | 20. Mai 2013

Absolutely true...the effect of a headwind/tailwind is dramatic with the MS. A 20 knot headwind means you are using Kwh as if you are driving 90 mph when you are actually doing 70, only worse because you're not actually traveling 90 miles in an hour.

The effects should definitely be taken into account when driving cross country. Drafting helps in a huge way.

lolachampcar | 20. Mai 2013

The corollary to that is the difference I have found doing 70 mph by myself versus in a group as normally happens on the interstate. I was surprised to find I often make rated range when in a pack while significantly less by myself.

cb9 | 20. Mai 2013

I'm only familiar with drafting on a bicycle, and then I need to be a few inches off the rear wheel of the rider in front of me. Just curious what "in a pack" and "drafting" means in a car. I'm assuming the "2 second rule" (which never happens in any highway I'm on) is incompatible with drafting. But how close do you have to get to tailgating? If I can see road between the hood of my car and the car in front, is that close enough to get a benefit?

d_kaufman | 20. Mai 2013

There is a lot to be said about this:
Drafting behind a bicycle, the object in front of you has a pretty small wind profile-compared to a truck.

Going from Harris Ranch to Folsom by way of Gilroy adds 2+ hours of drive time, but takes you completely out of the margins for range. You could have gone 70-80 mph with plenty of battery to spare.

What I would really like to see-from Tesla or from EVTripPlanner-is a real-time comparison between projected range and battery use with the actual values. That way, you could see before the Los Banos turnoff whether to continue straight to Folsom, or head west to Gilroy.

EVTripPlanner | 20. Mai 2013

At we do a "weather sensitivity chart" that shows energy consumption with head/tailwind. We have also done some actuals (from Tracker) vs. projections (from Planner), but are working out some wrinkles and haven't published a way for users to do this. Our plan is to use it to tune our algorithms.

Of course, all this should be integrated into the Nav system in-car, but we don't have open APIs to do that. Undertstandable that Tesla might not be too quick to open up the SDK given the liabilities involved (and resources from them that could be working on shorter-term emergencies and revenue-generation).

jk2014 | 20. Mai 2013

I wonder if this next software update will include the rumored elevation, weather conditions (wind speed, temp), etc. for trip planning and effective range estimates as specific average driving speeds?

anxman | 04. Juni 2014

This is a friendly warning that the drive from the California Buelton SC to Atscandero is an uphill drive and you'll face severe head winds.

I left Buelton heading north bound on I5 this past Sunday and the 200 miles of range barely made it the 130 miles. I strongly encourage waiting for either a full charge in Buelton or doing it at 60mph in range mode.

robkal007 | 04. Juni 2014

Winds really make a difference - help and hindrance. Currently charging at RV Park in Central Kansas and have 225 miles to go to Kansas City and my nights rest. Wind is gusting to 30 from the NW, but shifts to the north and then northeast in the late afternoon-evening. All this from which shows surface winds. My strategy is 55 miles an hour and pull in behind a moving van or bus and stay 20-30 feet back. Driving that way this morning made for 265 Wh/mile at 66 mph. Drafting seems to be worth 10-12 miles per hour of speed put in another way. The option, of course, is to SLOW DOWN.

PatT | 04. Juni 2014

Of course traveling west with a north wind might require that you follow closer and to favor the right side of the lane. And then there is turbulence!

jordanrichard | 04. Juni 2014

Ok, drafting is for race car driving, not out on the highway. I generally keep 2 car lengths between me and the car in front of me. At that distance, I would be out of stream of air coming down behind the car in front of me. Also not every car you come up behind will have a profile that will benefit you. Yes getting behind a truck is a sure bet, but drafting is a dangerous was to try and save range.

I have an Uncle that was an overroad trucker and told me numerous stories of people drafting trucks to save on gas. One particular story was about a family that was drafting a semi when the rear left re-tread let go and hit and went through the windshield of the car, killing the father who then obviously lost control of the car which crashed. He didn't say whether the rest of the family died or not from the crash, but his point was made.

Sniper | 04. Juni 2014

We put a TON of miles on every year on our Goldwing, the turbulence behind some vehicles is CRAZY!! Trucks do have a lot of calm air close in, but I will never ride that close, 2 - 3 car lengths back feels like you are in a mix-master. Most of the sub-compacts are worse than semi's not kidding, we try to ride in clean air as much as possible. (not easy) If you drop your speed to optimize your range, remember to check the speed at which you "auto lower" you want to be as low as possible to reduce drag.