A UPS typically includes the inverter, battery and battery charger in one stand-alone unit. However, there are UPSs that use external batteries, and has made inverters with battery chargers, so the differences blur as features proliferate.

UPS’s also can have communication with the equipment that it is powering, which lets the equipment know that it is operating on standby, giving it shutdown warning, or communicating with the human in the loop. Only some inverters have this communication.