I own a Neato XV Signature, vacuuming robot, which I bought almost a year ago. During my first attempt to let it run, its batteries lasted long enough to be able to vacuum the assigned area at least once, which took about 40 minutes (as it does today). I had also gauged the size of the area it should vacuum, in hopes that the robot would not need to return to its base station to recharge, in the middle of its job, even though that is a task which it can also accomplish – in most cases.
But then, after having let this robot vacuum my floor 3x per week, the battery life became shorter. Eventually it would need to break off at least once, to recharge, after which it would complete the job. By that time 1 battery charge was only lasting for 30 minutes. And finally, the robot needed to make three stabs at completing the same assigned area, thus recharging twice automatically before it was done.
So it seems logical that the robot simply needed a new set of batteries, which I just installed today. But, those were Nickel-Metal-Hydride batteries, which I think are usually supposed to last longer than just a year. For example, my electric toothbrush still has the same Ni-MH batteries it was originally equipped with, and continues to work after 20 years, with proper battery maintenance.
I always had the suspicion that the robot was over-charging the batteries consistently.
(Edit 11/10/2016 : ) This suspicion arose, because when I left the robot connected to its docking stand continuously, in spite of only working briefly, three times per week, its indicator-LED would switch back and forth between the solid-green-I-am-full and the blinking-green-I-am-almost-full within short intervals – more often than once per day. Considering that the unit had not been working, this was an incorrect sign, which it no longer shows, with the new batteries calibrated.
After I installed the new batteries today, I followed instructions on the Web, according to which we are also supposed to perform a battery calibration, and then the idea struck me, that the early demise of the first set of batteries may have been partially my own doing.
When I first received this robot, I did not perform any initial calibration – of its first set of batteries. Now that I have allowed the robot to do so, it is capable of vacuuming my entire floor space twice in one shot, which takes it 1 hour and 15 minutes of continuous running.
If everything worked as planned, This Defined the Voltage-End-Points, of One Charge-Cycle. However, it is a disappointing drawback of this model, that it gives no feedback, of whether the calibration was in fact a success or not.
Mind you, it was never written in the instructions that came with the Neato XV Signature, the way I received it, that we should do an initial calibration, but doing so might in hindsight have prevented incorrect charging behavior the first time around.
I know one person myself, who bought the same robot, who was not actually much of a Technology Person, but who was systematic enough in her ways, actually to do a calibration, before setting her robot on its first chore.
And it is also commented on the Web today, that sometimes a recalibration will be helpful – for a while – in spite of keeping the first set of batteries.