Most of the best front and rear dash cam on the market has a built-in battery. Many users have a misunderstanding about the built-in battery that it is the main power for the dash cam. The built-in dash cam is like the fire emergency light, once power cut, it can provide emergency light, but it easily consumes the stored charge. So the built-in battery of the front and rear dash cam isn’t like mobile phone and camera in standby mode for a long time. Because it is designed to take the car battery as the main power supply, there is no need to store a large capacity for electricity.
The design of no built-in battery is for our safety because the car often exposed to the sun in summer, the temperature of inside car is at least 50 degree. If the dual lens dash cam still works, it easily exploded. Just think why we don’t take our mobile phone exposed to the sun for two hours. Of course, that doesn’t mean that a dash cam with a built-in battery is not safe because as long as the built-in battery of the dash cam does not work, there will be no safety danger.