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Automatic Battery Capacity Selection

When you request the read_battery permission, users will automatically be prompted to select their vehicle’s battery capacity during the Smartcar Connect flow if we cannot determine the specific capacity for their vehicle(s). This ensures accurate battery information for your application is readily available.

Battery capacity selection during Smartcar Connect

For users that skip the selection prompt or were connected prior to September 18th, 2025, you can still launch the battery capacity selection flow manually using the URL provided by the GET /battery/nominal_capacity endpoint.

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Append your redirect URI

Smartcar will provide a URL with the following parameters from the GET /battery/nominal_capacity endpoint: 
https://connect.smartcar.com/battery-capacity
?vehicle_id=36ab27d0-fd9d-4455-823a-ce30af709ffc
&client_id=8229df9f-91a0-4ff0-a1ae-a1f38ee24d07
&token=90abecb6-e7ab-4b85-864a-e1c8bf67f2ad
&response_type=vehicle_id
&redirect_uri=
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vehicle_id
string
required
The Smartcar vehicle Id.
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client_id
string
required
The client_id from the Smartcar Dashboard for your application.
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response_type
string
required
Must be set to vehicle_id.
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redirect_uri
string
required
The URI you would like the response sent to after a user exits the flow.NOTE: this is the only parameter that will not be prepopulated as part of the API response. You must append it in order to launch the flow successfully and receive confirmation the user has exited the flow.
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token
string
A token to validate that the URL was provided from a battery capacity response for your application. The token is valid for 30 days. If a token is not provided or is no longer valid, the user will be directed to re-auth prior to selecting their capacity.

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Response

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Success

After the user selects a capacity and completes the flow, Smartcar will send the following to your redirect URI:
Success
https://example.com/home
?vehicle_id=36ab27d0-fd9d-4455-823a-ce30af709ffc
&selected_capacity=80.9
&reason=battery_capacity
Upon receiving a success response, you can access the selected_capacity by calling the GET /battery/nominal_capacity endpoint to view the selection in the capacity.nominal field.

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Error

When you redirect the user to select a battery capacity and they select “I don’t know the battery capacity”, Smartcar will send the following to your redirect URI:
Error
https://example.com/home
?error=battery_capacity_no_selection
&error_description=user did not know battery capacity
&vehicle_id=36ab27d0-fd9d-4455-823a-ce30af709ffc

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Flow Example

User selected battery capacity flow