Rechargeable battery powered circuits

Hey Guys, my name is Luc from Montreal, Canada.  Graduated automated systems engineering in 1999 but converted to full time programming after that.  I only recently started getting back into electronics and now I'm buzzing with ideas of things I want to build! 🙂

One tutorial I would love to see here would be on how we could have a battery powered circuit that we don't need to disassemble to recharge.  So in short, a circuit where we could just plug a micro-usb cable and the battery would recharge without any further manipulation.

The project I'm working on in my spare time is an electronic scoreboard for sports, the kind you would have by a volleyball court where the referee would flip the points manually each time a team scores.  (Dimensions of about 2x1 feet). 

In this case, the scoreboard would make use of an ESP8266 (Arduino with WiFi) and upload the displayed score to a server as the game progresses.  I still have to figure out how to create a low powered display system but I'm thinking of creating four 7 segment digits where each segment would simply be a colored piece of cardboard that would flip from it's black to yellow surface via small servo motors (the 1$ kind).  The advantage of this system is that once the 7 segments are set to display a number, it no longer consumes current until the next point is scored.  The segments would also be more visible in direct sunlight than a led based display.  Not too complicated but I'm thinking of building 10 of these scoreboards for a beach volleyball center that has 10 courts.  When the day ends, the league administrator has to be able to bring these 10 scoreboards inside and set them to recharge for the next day.  This is where I need to figure out how to power my project with rechargeable batteries that do not require much more manipulation than plugging in a micro-usb cable.  Scoreboards would work for up to 12 hours in a row and then recharge overnight (~8h).

What do you guys think?