Trust the trip planner

I mentioned in the last post the Tesla in vehicle trip planner.  The trip planner is part of the Tesla navigation system.

Every time you use the navigation system to go from point A to point B the software plots out a route (turn here, go x miles, turn there, etc).  Same as every other navigation system (Waze, Google Maps, Garmin).  In addition the Tesla nav system also estimates how much energy you need to get from A to B.

Imagine if a normal gas car had this navigation system.  Let's say you want to go on a thousand mile trip starting with a full tank of gas.  The nav would say you can't make it with just one tank of gas.  It would tell you how many times you need to fill up, navigate you to the gas stations to fill up, and tell you how much gas to put in at each gas station.

Well that's what the Tesla navigation does except with electricity and chargers instead of gas and gas stations.  It tells you if you can make it from point A to point B with the amount of "gas" you currently have "in the tank".  And if you can't make it to point B it will navigate you to a charging station on the way and tell you how much to charge the car in order to make it to point B.

Now the magic.  The trip planner uses the distance, average speeds on the route, and elevation changes along with the vehicle energy use per mile in order to estimate how much energy it takes to get from A to B and whether you will make it.  

In this example the trip is 50 miles long (X axis labels).  The vehicle has 60% of a "tank of gas" at the start.  Estimate at the end is 42% of a tank of gas left.

Now as you go along the trip the planner updates it estimates periodically.  If you are using too much energy (going faster than the speed limit, cold weather, rain, wind) the estimate will start to diverge from actual usage and the trip planner will reflect this.

In the example below the trip planner estimated about a 38% reserve at the end of this trip (grey line).  The actual usage (green line) started to diverge about 15 miles into the trip.  At the end of this trip the actual reserve will be about 32%.  

Where this really comes in handy if you are pushing the limits of range.  Say going long distances pulling a trailer 👀 You can see in real time if the actual usage starts diverging from the estimated usage.  If this happens you can drop your speed in order to save energy.  Or pick a closer charging opportunity than originally suggested. 

And if the actual use really diverges from the estimate you'll see this (thankfully in all the years of driving electric this warning has only happened once).

Bottom line...Tesla in vehicle trip nav and trip planner is great for giving you piece of mind that you can get from to your destination.