So, yes, I have been using the UPS for over a year and it used to work
perfectly. In fact, the reason for which I now for the first time tried
to connect it via usb is that I was having sudden power failures and I
had the impression that these were affecting only the UPS i.e. equipment
not connected to the UPS was working fine, and I wanted to see if there
really was a hardware problem with the UPS - and was too lazy to
disconnect everything and test it properly.
I have now removed the UPS and tested it separately and found out that
in spite of being "fully charged" it will switch off after less than a
minute of power supply being disconnected, so there definitely is a
hardware problem. Such as: the battery is totally gone.
Thanks to all for the tips!
--
Michele
