APC's Network Management Card exposes battery status, load and runtime over SNMP. Here's how to turn it on and what Linivo reads from it.
In the Network Management Card's web interface, go to Configuration > Network > SNMPv1 (or SNMPv3 for encrypted access) and enable access.
The factory-default read community on most APC cards is publicly known; change it before exposing the card to anything beyond an isolated management VLAN.
Linivo polls load percentage, battery runtime remaining, input/output voltage and on-battery status from the standard UPS MIB, and can alert the moment a unit switches to battery power, not just when it eventually fails.