I recovered a thrown-away UPS with the initial plan of cannibalizing some components, but then I decided to try recover it to working conditions if possible, if impossible go on with the initial plan.

Step 1: Restoration

I recovered a thrown-away UPS with the initial plan of cannibalizing
some components, but then I decided to try recover it to working conditions if possible, if impossible go on with the initial plan.

Usually UPS stop working because of the "dead" battery, because under load its voltage drop too low to power the circuit that converts the 12V-DC back to 220V-AC.
In case the problem were not the battery, the next or maybe the first to thing to check is the fuse. cause is also cheaper to replace than the battery, but is also lesser commonly the guilty component than the battery.

If the fuse is burnt connecting a new battery would make the UPS apparently work but the battery would not be charged (so you can ruin a new battery). So both check that ups runs on battery alone(with AC plug disconnected) and that connecting the AC plug the UPS changes its mode(usually when powered it stops making an annoying sound that reminds you it's running on battery)

Then (of course with AC UNPLUGGED for safety!!) I opened the enclosure unscrewing some screws and extracted the original battery to check it. without load its voltage was correct (a little more than 12V) but once connected back to the UPS and switching-on the UPS the voltage dropped to about 10V. then just to test the circuit I replaced the original battery(the smaller 12V 4.5AH) with a spare one I already had that is bigger (12V 7.2AH) and the UPS worked perfectly. then with the enclosure closed I checked it with AC connected and the

The only concern was the battery much bigger than the original, then I was considering buying a smaller one, put the bigger battery outside the enclosure, and other options but then i realized that with some effort also the bigger battery could fit into the enclosure.

So the UPS was already restored to working conditions, and with longer endurance, but I was not satisfied yet.

Step 2: Modification

I was not satisfied because unlinke other UPS this one had not standard wall sockets, instead had only three IEC C-13 output connectors and the inlet C-14 connector.

So I decided to modify my UPS to have at least one more usual "Schuko" socket.

To do this I removed a C-13 with the help of a little screwdriver

then enlarged the hole, using a manual saw and a file, to accomodate the panel mounted Schuko socket and connected the wires.