EV routing in HERE Routing API v8
The EV routing features of the API extend the routing service with electric vehicle specific options.
Routing responses can contain details of energy consumption of the vehicle on the route.
Route calculations can also add charging stations to the route, to ensure that destination can be reached without running out of energy, while still optimizing the result for overall travel and charging time.
For code samples, see these tutorials:
- Calculate consumption per section
- Calculate state of charge along a route
- Calculate a route with charging along the way
- How to use vehicle[speedCap]
Consumption calculation
Energy consumption for EVs can be calculated using one of two models: physical and empirical.
Read the following documents to learn more about these models:
Charge levels along the route
On top of the consumption model, HERE Routing API v8 allows you to specify the battery parameters of a vehicle to return the charge levels at each waypoint along the route including the final destination.
| Request parameter | Required | Description |
|---|---|---|
ev[initialCharge] | Yes | Charge level in kWh of the vehicle's battery at the start of the route. Required to calculate state of charge en route. |
ev[maxCharge] | Yes | Total capacity of the vehicle's battery (in kWh). Required to calculate state of charge en route. |
Charging time at a charging station
The Routing API allows you to specify the charging parameters of a vehicle as well as charging preferences of a user to calculate the charging time at a charging station.
Charging parameters of a vehicle:
| Request parameter | Required | Description |
|---|---|---|
ev[maxCharge] | Yes | Total capacity of the vehicle's battery (in kWh). |
ev[chargingCurve] | Yes | Function curve describing the maximum battery charging rate (in kW) at a given charge level (in kWh). |
ev[maxChargingVoltage] | No | Maximum charging voltage supported by the vehicle's battery (in volts). |
ev[maxChargingCurrent] | No | Maximum charging current supported by the vehicle's battery (in amperes). |
ev[maxChargeAfterChargingStation] | No | Maximum charge to which the battery should be charged at a charging station (in kWh). Required when ev[makeReachable] is set to true. |
ev[maxPowerAtLowVoltage] | No | Maximum power at which the vehicle can charge from a charging station supplying at a voltage < 800 V, while ev[maxChargingVoltage] >= 800 V. Defaults to 45 kW. |
Charging preferences of a user:
| Request parameter | Required | Description |
|---|---|---|
ev[minChargeAtChargingStation] | No | Minimum charge when arriving at a charging station (in kWh). |
ev[minChargeAtFirstChargingStation] | No | Minimum charge when arriving at a first charging station (in kWh). |
ev[minChargeAtDestination] | No | Minimum charge at the final route destination (in kWh). |
ev[chargingSetupDuration] | No | Time spent (in seconds) after arriving at a charging station but before actually charging. For example, time spent for payment processing. |
ev[maxDrivingTimeBeforeCharge] | No | Maximum driving time (in seconds) before the first charging stop. See Set maximum driving time before charging. |
ev[minTimeAtFirstChargingStation] | No | Minimum duration (in seconds) at the first charging stop, including charging time and subsequent waiting time. See Set maximum driving time before charging. |
Charging time calculation
chargingCurve is the main parameter to describe the speed of charging the battery.
chargingCurve specifies the maximum power that can be accepted by the battery at a given state of its charge.
If the battery has more fine-grained limitations on components of the power - namely voltage and current - then the request can specify these limitations by means of the optional maxChargingVoltage and maxChargingCurrent parameters.
These two parameters can better estimate the effective power of charging when charging stations offer voltage and current outside of acceptable range for the battery, while the offered power is still within this range.
If a charging station's supported voltage is less than 800 V but the vehicle's maxChargingVoltage is higher than this, the power of the station will be capped to 45 kW for calculating the charge time. This is to account for the fact that higher-native-voltage vehicles cannot draw the rated power when connected to a lower voltage stations. The power cap to 45 kW can be overridden using the parameter maxPowerAtLowVoltage, if the vehicle can draw higher power from these stations.
The charging time is calculated assuming the battery is able to charge at 90% of the power that the vehicle can draw from the charging station connector.
Example
Given the following conditions:
chargingCurve: constant charging at 150 kWmaxChargingVoltage: 400 V- Charging Station A: max power: 150 kW, voltage 400 V, current 375 A
- Charging Station B: max power: 150 kW, voltage: 800 V, current: 187.5 A
The voltage of station A is within the limit specified by maxChargingVoltage. The consumablePower is therefore 400 V * 375 A = 150 kW.
The voltage of station B is greater than maxChargingVoltage. The consumablePower is computed as 400 V * 187.5 A = 75 kW.
Determine the maximum charge at a charging station
maxChargeAfterChargingStation allows to limit the maximum charge at a charging station during EV route planning.
This parameter is aimed to specify the hardware limitation of the battery as suggested by the manufacturer.
This parameter should not be used to instruct the EV routing algorithm about the "optimal" charge level.
The resulting charge value after visiting charging station may be lower than the value of this parameter.
The algorithm considers various charge levels at each potential charging station, and tries to optimize the total route duration (travel time plus charging time) while ensuring that the route is reachable.
For example, if there is a fast but not reachable charging station on the route, the algorithm prefers first to charge at a slower station, but only to a level that enables it to reach the fast station.
This way, the result is the best possible combination of driving and charging parts.
Add charging stations to ensure a reachable route
On top of the consumption model, the initial charge level, and the parameters to calculate the charging time, the Routing API allows you to request a reachable route optimized for the total travel and charging time.
If necessary, charging stations are added to the route to achieve reachability.
| Request parameter | Required | Description |
|---|---|---|
ev[makeReachable] | Yes | When set to true, the router ensures that the calculated route is reachable within the given constraints. |
ev[connectorTypes] | Yes | Comma-separated list of connector types that are compatible with the vehicle. |
ev[chargingCurve] | Yes | Function curve describing the maximum battery charging rate (in kW) at a given charge level (in kWh). |
ev[maxChargeAfterChargingStation] | Yes | Maximum charge to which the battery should be charged at a charging station (in kWh). |
ev[preferredBrands] | No | Comma-separated list of charging station brand IDs. If ev[makeReachable] is set to true then charging stations from the specified brands will be preferred as potential charging stops, even if this makes the total route duration (travel time plus charging time) longer (up to 15 minutes per charging stop). |
ev[preferredChargePointOperators] | No | Comma-separated list of charge point operator IDs. If ev[makeReachable] is set to true then charging stations with specified charge point operators will be preferred as potential charging stops, even if this makes the total route duration (travel time plus charging time) longer (up to 15 minutes per charging stop). |
ev[eMobilityServiceProviderPreferences] | No | Comma-separated list of eMobility Service Provider ID and a preference level (High, Medium, Low, Exclude). Charging stations supporting eMobility Service Provider with higher preference level are preferred as charging stops. For more information, see the API Reference. |
Note
preferredBrandsis deprecated, usepreferredChargePointOperatorsinstead.
Users can specify a default preference level in parametereMobilityServiceProviderPreferences, example:default;preference=Low, default preference level is applied to stations that do not support any of the specified eMobility Service Providers, If user does not specify default preference, it is set toexclude, i.e. a station not supporting any of eMobility Service Providers specified in preferences will never be chosen as charging stop, User can specify any preference level for default preference, However it is not advised to assign a preference level higher than the lowest preference level specified for eMobility Service Providers. For more information, see the API Reference
Charging stations
The Routing API only considers DC type stations for the following reasons:
- Full charge at an AC station takes much longer (a few hours) and this doesn't fit the use case of EV Route planning with charging along the route.
- The charging network of DC stations already provides sufficient coverage. For details, see EV car routing coverage.
HERE EV Charge Points API v3
The Routing API returns the Location ID of the charging station(s) added to the route. This ID can be used with the HERE EV Charge Points API v3 to retrieve further information about the charging station, as described in the tutorial. IDs of Charge Point Operators (CPOs) and eMobility Service Providers (eMSPs) to be used for ev[preferredChargePointOperators], ev[excludeChargePointOperators], or ev[eMobilityServiceProviderPreferences] can also be retrieved through this service, as described in the metadata tutorial.
Previous versions of the developer guide referenced the v2 version of the HERE Charge Points API. For users migrating from v2 to v3, use this migration guide to update your implementation with the new version of the service.
Updated 19 days ago