This is regarding home UPS/inverters which are typically known to convert the DC from the battery to AC, so the AC can be used for household purposes.
What I don't understand is how the batteries are charged.
From my understanding the 12V or 24V batteries be it lead-acid or Li-ion are charged using DC current. The batteries don't understand AC current either for input or output. They take DC and output DC. But the typical household gets AC current.
Which device is converting the AC to DC for the batteries to get charged?
Is it done by the UPS/inverter device?