Automating power management has always been a difficult problem for me to solve with my robotic platforms. Ideally, I'd like to simply plug my bot in to an external supply, and have a control board handle recharge of the on board batteries while continuing to power the bot, all while providing battery information to the primary controller via a bus (e.g. I2C). I've designed some simple controllers of my own, but actually constructing and debugging can be a chore, and I rarely see any affordable commercial solutions. My approach has been to design a modular system of separate routing, recharge, and supply boards, which would detect the presence or absence of an external supply, and then use FETs or relays to reconfigure the supply lines appropriately. My goal is to avoid having to redesign an entire board every time my bot's power requirements change slightly. How does everyone else handle this issue?
Chris