Conflicting distances to a supercharger

Conflicting distances to a supercharger

On Sunday I am heading to Cape Cod from CT and will be using the E. Greenwich, RI SC. Per Google Maps, it is 66 miles from my home. If I go to the SC list in my car, it says it's 54 miles, yet when I select that SC and nav directions pop up, it says its 94 miles. Why the disparity?

SCCRENDO | July 31, 2014

Before you put in directions it gives distance as the crow flies. Hence a shorter distance than the Nav. Google maps must be giving you a more direct route whereas the nav must be using freeways and a longer route. Not knowing where you are I entered Connecticut to E. Greenwich RI and it looks about 90 miles. There are 3.possible routes offered.

Captain_Zap | July 31, 2014

When you just look at distances to locations, the measurement is "as the crow flies". After you tell the nav system to navigate to the location, it will calculate the distance via highway.

I asked Tesla about this last year. They said they needed to do this because there is not enough memory to have every route pre-calculated on the system.

jordanrichard | July 31, 2014

"crow flies" would explain the shorter distance, but what is the point to listing that kind of distance when I am not driving a crow....:-)

Captain_Zap | July 31, 2014

I don't know, but I think that the mileage I got was via seagull.

Sure, the distance was 5 miles as the seagull flies, but to drive it the trip is 120 miles. It was easy for me to catch that discrepancy.

I'm still waiting for an amphibious Tesla.

DLebryk | July 31, 2014

You might cross reference the route on the NAV with Google Maps. Sometimes the NAV will take you down an extra long path to a Supercharger. The NAV tends to like four lane interstate highways and avoiding cities. Sometimes that can be a long ways out of the way.

I discovered this during our round trip between Chicago and Phoenix trip. Almost by accident I compared the NAV route to Google Maps on my phone. There were better routes offered by Google Maps (you can also play the what if game - you can't do that with NAV).

There was a leg between Phoenix and Holbrook, AZ that I would not have made if I followed the NAV. There is a short cut at Heber that lops off around 50 miles and a half hour of travel time.

Between Gallup and Farmington there was another short cut that avoided two towns and about 10 or 15 miles.

That as the crow flies drove me nuts during this trip. I learned you always have to start your trip with the NAV to be certain you have enough charge to make it to the next station. Read the total distance on the directions panel, and then charge to 50 or more extra miles.

Brian H | August 1, 2014

50 mi and a half hour? Are you driving 100 mph? What range do you get?

Bighorn | August 1, 2014

~2.5miles/kWh or 400Wh/m, give or take.

centralvalley | August 1, 2014

There is still a need for the old-fashioned, fold 'em up paper maps that we oldsters still use. Don't leave home without them!

Rocky_H | August 1, 2014

@centralvalley, is there an app for that fold'em up paper map you're talking about?

SCCRENDO | August 1, 2014

@BrianH I think he meant the detour occurred at 50 miles not that it decreased the distance 50 miles but I guess if it were so would need to take on some extra charge.

jordanrichard | August 1, 2014

The route that the car suggested was indeed all highway and went way out of the way. The route that is more direct is a 2 lane road, speeds averaging 50-60 mph. Still though that is 66 miles not the 54 listed on the SC list page.

I asked the guys at the service today and they had no clue as to why it would list a "as a crow flies" distance.

tnisbum7 | August 1, 2014

Hate to say it, but the navigation system is just OK at best. Do yourself a favor and use Waze on your phone to double check anything the nav tells you to do. Waiting on 6.0 before I go postal on Tesla and whatever Garmin database rev they are using. In Atlanta some roads over two years open are still not in the database. (McGinnis Ferry extended to Lawrenceville-Suwanee for example). Do not follow directions out of the Savannah supercharger. Almost comically out of the way back to I95.

DLebryk | August 2, 2014

Brian H - whoops - I just remember sweating about getting to the charging station.

It really was 17 miles and 20 minutes. Sorry for the mistake.

Rocky_H | August 4, 2014

@jordanrichard, as to the "why" of using the straight line crow flies distances, it's a speed and technical thing. When you pull up the list, it can come up almost instantly with those numbers, because it has the X,Y coordinate of the car right now, and the X,Y coordinates of those chargers, all in the car's computer already. That's just a quick list of subtractions that can be done in micro- or nanoseconds by the microprocessor. Listing the navigation distances, though, would have to submit each route over 3G to Google Maps and get a response back, which can take a few seconds each.