How long a tablet’s battery lasts determines how long it will function away from sources of power. No battery life measurement can be completely accurate, as different uses will put different strains on the battery. The more things a tablet is doing, the faster the battery will drain. Such as WiFi should be turned off if it isn’t being used and the tablet is away from a source of power, and unused apps should be closed.
The Dragon Touch K8 Kids has a stated battery life of only three hours. This is on the low side when it comes to children’s tablets. Should the tablet be in a car, especially on a long journey, then it can make sense to pick up an in-car battery charger.