How to Add Your Car to ABRP
Introduction
One of the questions we get fairly regularly at ABRP is if and when we will support other Electric Vehicles in the planner. To create a model the planner can use we need two aspects defined: Driving Consumption and Charging.
Once we have a model for a car, we have three markers we’ll put in the planner:
- Alpha – An initial model based on measurements or data by external parties, not thoroughly verified.
- Beta – A more mature model validated by matching to owners’ actual road trip numbers
- Release – Model verified and improved by recorded real life driving data.
Once you have the data we need to make Driving Consumption and Charging Models, email it to the ABRP Team, and we’ll work with you to get the model on the site. We won’t make any car model available on ABRP without first verifying accuracy with an actual owner of a car, so it helps immensely if you’ve got an example road trip you can recreate in the planner once we’ve prepared the model.
Emails:
- bo@abetterrouteplanner.com
- jason@abetterrouteplanner.com
Driving Consumption Model
The driving model is the most important part of the planner, as it calculates how much battery you’ll use on each leg of the trip. To do this calculation, the planner uses a third order polynomial to calculate consumption. This is based on the physics of driving. There are several ways to create this driving model, listed here in order of accuracy:
1 – Analytical Physics Model
Creating an analytical model requires the least access to a car, but it’s the least guaranteed to be accurate. To create an analytical model, we use the physics of driving:
P_{drag} = η*C_{d}*A*v^{3}
P_{rolling resistance} = η*C_{rr}*M*g*v
P_{idle} = Constant
Combining these three terms, we get a full equation for the consumption of a given car. We then multiply by the drivetrain efficiency, what percent of battery energy goes into creating motion. To create this model, we need to fill in a few variables:
Parameter | Description |
---|---|
C_{d} | Coefficient of Drag - Typically available online, but takes a little bit of research to verify. |
A | Frontal Area - Cross-sectional area of the vehicle. This can be calculated roughly from front or rear photos of the vehicle and the vehicle's dimensions |
C_{rr} | Coefficient of Rolling Resistance - Mainly based on the tires, and drivetrain of the vehicle. A little harder to dig up. This typically varies from about 0.007 for very efficient tires to 0.014 for wide performance tires. |
M | Mass - Curb mass of the vehicle. |
P_{idle} | Idle Power - The amount of power drawn by the vehicle when sitting still. Best drawn by looking at the built-in energy meter while at a stop. Typically around 1-1.5kW |
η | Drivetrain Efficiency - Efficiency of turning battery power into movement. Generally between 85%-95% |
If you can provide all of these parameters, we can create a model that is fairly accurate.
2 – Manually Collected Driving Data
The next-best method is calculating the driving model from approximate real-world data. This can be gathered by recording consumption while driving. By observing the power draw at various speeds on flat ground, and providing data points we can calculate a better consumption model.
In general, we need the highest number of data points at freeway speeds, as you tend to spend most of your driving on a trip at those speeds. I would recommend noting the power consumption readout at the following speeds (km/h and mph are not exactly equivalent, for ease of use, please note which unit you used to collect data so our model can be as accurate as possible).
If you plan to use this method, be sure to drive safely, you may want to recruit an assistant to take the power draw notes while you drive.
Speed (km/h) | Speed (mph) | Power (kW) |
---|---|---|
30 | 20 | |
45 | 30 | |
60 | 40 | |
75 | 50 | |
90 | 55 | |
100 | 60 | |
110 | 65 | |
120 | 70 | |
130 | 75 | |
140 | 80 | |
150 | 85 |
3 – Collecting Driving Data Directly
This is the best way to build an accurate model. This can vary by vehicle or manufacturer, but most vehicles provide data via the OBD port. For an example, see the for the generic OBD and Torque instructions. To contribute data this way, set yourself up with Torque Pro, and find a PID list for your car.
If you can find these things, and can verify the data shown on the Realtime Information display in Torque is accurate, contact me (jason@abetterrouteplanner.com) to set up the server to receive your data.
Once there’s enough data for your vehicle, we’ll perform the same analysis we’ve done for all the currently released models in the planner.
Charging Model
The charging model is a little easier to build from available information. If you can find a plot of the maximum charging speed relative to State of Charge, or a video that shows power in kW and battery %, we can build a charging model from that. Something like the following chart (sourced from Fastned for the Hyundai Ioniq):
Fastned charging data for the Hyundai Ioniq
Again, however, the best way to build a charging model is to contribute OBD data directly from a charging session. See the setup instructions in the previous section for what’s needed to submit OBD data.
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