A storage maintains charge times for vehicles. A processor of a server is programmed to periodically determine a time interval since each of the vehicles has been started according to the charge times. The server sends a message over a wide-area network requesting remote start of one of the vehicles responsive to the time interval for the one of the vehicles indicating no engine restart for at least a predefined time period. A processor of a vehicle restarts the vehicle according to receipt of a restart request sent responsive to a periodic process performed by a remote server to identify that a most recent vehicle start time sent from the vehicle to the remote server is at least a predefined time interval from a current time identified by the remote server.