More info on my blog: http://wiknology.blogspot.com/2014/06/new-and-improved-3d-printed-clock.html

PowerBoost 1000C is the perfect power supply for your portable project! With a built-in load-sharing battery charger circuit, you'll be able to keep your power-hungry project running even while recharging the battery! This little DC/DC boost converter module can be powered by any 3.7V LiIon/LiPoly battery, and convert the battery output to 5.2V DC for running your 5V projects.