I was just playing with Sweepy for first time... Docking station was separate from main energy lines, with own battery and generator. I turned off the generator just to see what Sweepy will do without power.
And... It's not only stuck trying to recharge, but also animation of Sweepy's Dock is stuck with "working/charging" animation, despite being without energy. While I was expecting thing go to sleep, or standby, or be dead, it still for at least 5 or 8 cycles tries to recharge.
Sweepy's Dock charging animation with no energy