The OpenUPS2 was designed to provide user specified regulated power output from a wide input voltage or battery backup, microprocessor assisted LiFePO4 battery charging and cell balancing in a single PCBA. Battery cells are inserted in the device, no need for special cabling between cells and UPS. The UPS contains a synchronous boost converter with high accuracy voltage and current regulation and automatic system power path selection from adapter or battery. It charges the battery in three phases: preconditioning, constant current mode and constant voltage mode.