Open source 60W small UPS power supply reference design

Ideal for running network devices such as small switches, home routers, and WLAN access points. The design files, firmware, etc. of the DC uninterruptible power supply are open sourced. Key Features: - 3 DC outputs - Selectable output voltages (9V/12V/12.5V/15V) - USB-C power output (5V only, 3A) - Built-in, easy-to-replace batteries (2x Li-ion 18650) - With Comprehensive built-in Prometheus exporter - open source firmware (based on ESP32, esp-idf framework) - easy software updates via rear USB port Author's Note Origin: For a long time, my home network (cable modem, router and switch) It is run through an ordinary line interactive AC UPS. This is never ideal for a number of reasons. First, the UPS uses sealed lead-acid batteries, but they don't seem to be used properly, causing them to not last long. I've also noticed that the UPS always gets a little warm, which indicates higher idle power consumption. In this particular setup, the core network components only use about 12W. The AC UPS alone uses 10W when idle, which is quite a waste of power. Another worrying factor is overall system reliability. For the AC UPS, three separate wall power supplies are used, each powering one device. To power all network components directly from DC, simply install a wall socket at the power input of the UPS itself. Additionally, I've never been happy with the monitoring options offered by AC UPS. While it comes with a USB port for monitoring, there are very few indicators available. The DC UPS provides an Ethernet port and hosts a Prometheus exporter, providing various metrics related to power input and output, temperature, battery health, and battery management internals. Finally, DC UPS are much smaller than the available AC UPS.