A good power supply is essential for the proper operation of the Raspberry Pi. A power supply of at least 3A (3000mA) of USB-C type is necessary for the new Raspberry Pi 4 (2GB, 4GB or 8GB). The power consumption of the Raspberry Pi is very low but it is advisable to have at least 2A (10W). If you use USB devices or your projects use actuators or sensors on the GPIO connector, it is best to opt for a 3A (15W) power supply. If the operating system freezes or the Raspberry Pi is unstable (unexplained restart), it is probably because of a power supply too low or poor quality.
Even with a quality SD card and power supply, remember to backup your data regularly or clone your SD card by following this tutorial.
5V / 3A micro USB power supply for Raspberry Pi or other nano-PC
This power supply may also be suitable for supplying your projects with connected objects based on ESP32 or ESP8266. Some generic Arduino development boards also use a micro-USB connector
5V / 3A USB-C power supply for new Raspberry Pi 4
The new models of Raspberry Pi 4 are equipped with a USB-C type connector. A power of at least 3A is necessary to power the new models of Raspberry Pi 4.
UPS HAT for Raspberry Pi
Expansion card (HAT) equipped with one or more high capacity batteries (18650) to power the Raspberry Pi 4 (or old models) in the event of a power failure (inverter or UPS system). The HAT UPS also makes it easy to develop mobile projects requiring battery operation. For example robotics, RC, autonomous navigation, data logger.