Window Washing Robots

We bought one for our home in the States. The battery did not have enough charge to clean a sliding glass door on one side. Charging took many hours. So to do a sliding glass door and an adjacent glass, both inside and out, took days. Yes, they are expensive. We also needed an exterior electrical outlet to do the side. The electrical cord was not long enough to come from the inside outlet in order to follow the machine on the outside of the window. I just got rid of ours. We cannot recommend it. Kathy