UPS battery backup

A UPS sits permanently between the wall socket and your equipment and switches to its internal battery within milliseconds when mains power fails. That is the difference from a power station, which you have to connect yourself: a UPS bridges a dip while you are not even there. Choose on output in watts or VA, on the runtime you need and on the shape of the output waveform. For critical equipment such as a NAS or a heating system, a pure sine wave model is the safe choice.