Surprise, surprise, it refused to start even after charging it for more than one day. I always got this never ending loop:
It successfully undocked from its docking station but it just reset whenever it tried to start the brushes which led me to believe it was a low battery problem.
Mixing various instructions I found on the internet, I ended up with this procedure which seems to fix the problem:
- Connect the Roomba and charge it completely (until the light turns green)
- Disconnect the Roomba from the charger (the light turns off)
- Turn on the Roomba by pressing the Start button once (the light turns green)
- Press and hold down the Dock and Spot buttons for 15 seconds to reset the Roomba (the Roomba turns off)
- Release the Dock and Spot buttons (the Romba plays the 5 tone startup sound)
- Go back to step 1
I have repeated the procedure 5 times so far and the run time keeps increasing.