I have a Focus Paralane Di2 Ultegra that was given to me and I cannot figure out where the charging port would be. I looked online and nada. The battery is in the seat tube, but the port is a different shape than the charger (SM-BCR2). There is no external place that I can see that it would plug into.
Did you check your handlebar ends? At the end of one of your handlebar ends there should be a port which is usually on the right (right as you would see setting on the bike).