APC S20 - Will it power up by itself after drained battery and utility power is back?

[Anonymous user]

Lately, I have 3 incidents within 25 days where my APC S20 (18 months old) will power off (due to a power outage blip) and will not power itself back up after the utility power is back. I have to manually restart it on site each time. I did not see "Battery needs to be replaced warning" or "Circuit Breaker is tripped". I have read some of the discussion online but have not seen a solid answer. 

Though the manual stated that the battery will continue to be charged (While APC S20 being OFF) on low acceptable voltage and will turn itself back on later. I find that it's not the case.

My house alarm w smaller backup battery seems to restore itself just fine. Yet, the APC S20, where I have all of my AV units and connected home devices connected to, seem to require a manual in place restart. And, the incidents seem to happen more and more. 

What advise could you provide? Is there a software or hardware button that I need to set to enable the auto restart?

Thanks in advance!