What happens when the battery gets low?

At 25 percent or less you receive a WhatsApp message asking you to finish the current ride and return to the hub to charge, and you are offered only rides that end within 4 km of the hub. At 15 percent or less the message tells you not to take new rides and to return now, and you cannot go online again until the car is above 15 percent. Between 23:00 and 05:00 the 25 percent message waits until 05:00; the 15 percent one does not. Every ride you are offered must leave 15 percent in reserve after the drive back to the hub.