Frequently Asked Questions

Why isn't charger XXX on EVTripPlanner?

EVTripPlanner gathers chargers from other sources, such as Tesla, Open Charge Map, and the Department of Energy. If a charger is not present, you can add it to the Open Charge Map database, but it may take a month or so to show up in EVTripPlanner because the database is updated infrequently.

Why doesn't EVTripPlanner work in the car's browser?

The Tesla browser is rather primitive and has poor Javascript support, so many rich web applications, including EVTripPlanner, will not work.

When will EVTripPlanner support the 60D, Model X, or other Tesla?

In order to develop an accurate algorithm, I need good data to learn from. You can help contribute data by using this app.
In the meantime, you can create a custom car and try to tweak it to model the car you want. That's basically what I do.

How do I print the EVTripPlanner results?

As of now, there is no good way to print it, but there are a few workarounds. You can take a screenshot of your screen and print that (if you're on Windows 7, just search for the "Snipping" tool). Alternatively, you can download the CSV version with the link on the left hand pane and print the spreadsheet. Maybe someday when I don't have midterms or finals looming I'll get around to fixing it ;)

What do the colors of supercharger icons mean?

When you use the "Route Thru Superchargers" feature, the chargers along the route are colored according to the energy it takes to get to them. Green means you should make it fairly easily, yellow means you probably can but if you enounter a headwind or unexpectedly hot/cold weather, you may have to slow down, and a red border means that you probably can't.

Using the EV Trip Planner

How It Works

EVTripPlanner uses a physics-based model to predict how much energy your EV will use along your route. It accounts for:

• Speed: this is usually the biggest contributor to variation in energy usage. We use Google Map's traffic-based estimate of current speed, which you can adjust up or down with the 'Speed Factor'.
• Air density: this varies with temperature and altitude. The same level-road trip at a higher altitude takes less energy than at sea level since the air is thinner. Similarly, the same trip (without air conditioning or heating) takes less energy when it is hotter since the air is thinner. We determine altitude over the route using the Mapquest database and use your input for temperature.
• HVAC: the heater and air conditioner, as well as any energy required to heat or cool the battery pack, use energy...even when you're not moving. We look at your cabin temperture setting and your estimate of the outside temperature.
• On-board Systems: the computers and other on-board systems use energy, even when the car isn't moving.
• Weight & Elevation Changes: the weight of the car and payload (entered) are used along with elevation changes along the route to determine energy used climbing...and recovered during downhills.
• Friction, efficiency, regeneration: each EV converts electrical energy in the battery to mechanical energy at the wheels a little differently (and vice-versa). We account for these conversions and differences.
• Your Car Model: each car has different parameters for how they use energy in the categories above. EVTripPlanner takes the best data available to match our model to the actual measurements and published charts.

Trip Settings

Setting the parameters for your trip is critical to getting an accurate estimate of the energy that will be consumed. The most important setting is your "speed factor", which is how much faster or slower than the prevailing speed (as estimated by Google Maps at the time of planning the route) you are going on average. Unfortunately, you can drive in different patterns and have the same average speed while consuming different amounts of energy. While these errors don't tend to be very large for long trips, the closer to "cruise control" you are at the average speed on long segments the closer the estimate will be. Also fill in payload, outside and cabin temperatures and your correct car model - these can make a significant difference.

Interpreting Results

EVTripPlanner has been used to plan over 50,000 routes for thousands of EV drivers. Many drivers report that EVTripPlanner predictions are very accurate - more than any other tool available. But you can't count on it being within let's say, 5%, all the time. You can hit unexpected traffic, weather conditions (especially headwinds) or have to make a last minute detour - so you should always have some margin for safety and a "Plan B" for where you would charge for any trip that is estimated to use more than about 80% of the available energy.

EVTripPlanner reports energy usage in two ways:

• kilowatt-hours (kWh): this is the actual energy used in direct engineering terms. Unfortunately, the Tesla does not report kWh remaining in the battery, which makes this measurement difficult to use in practice.
• rated miles: this is how Tesla reports remaining range (rather than kWh). In order to translate the kWh used by EVTripPlanner's model to Tesla (or other EV) rated miles, we need to use some conversion factor. Unfortunately, Tesla does not publish this number and with recent software releases it may not even be the same all the time. Tesla's trip meter also doesn't measure *all* energy used (if you add up energy/miles used plus rated miles remaining, it doesn't add up to the miles you started with after the last charge). We have made our best estimate, and it seems to correlate pretty well.

Since exact weather conditions all along the route are difficult to predict, we provide a sensitivity chart that shows how much energy would be used over a range of winds and temperatures.

Feedback

We are always interested in your feedback - good and bad, feature requests and defect reports. When providing feedback on route accuracy, please provide your route ID (after the ? in the URL) and information about your drive that might be relevant. Send to comments@evtripplanner.com

• You can now create custom cars

• Adding the name of a supercharger (e.g. "Buckeye supercharger") will not result in the correct location because Google has not yet learned the addresses of Telsa superchargers. To add the supercharger in the correct location, click the supercharger's icon on the map then click "Charge Here".
• Elevation in tunnels is incorrect, so energy usage on routes with tunnels may be somewhat too high
• Dragging only works with routes with 10 or fewer waypoints.

• Thanks to my dad, Cliff Hannel, for directing EVTripPlanner with new features and bug reports and really making the entire project possible
• Thanks to my brother, Jordan Hannel, for creating the initial prototype of EVTripPlanner as a proof of concept
• Thanks to my sister, Tess Hannel, for helping with the graphic design and UI of EVTripPlanner
• Routing brought to you by Google and MapQuest
• Chargers are provided by Open Charge Map and the NREL developers API