When a typhoon knocked out power for 14 hours, my UPS-powered laptop became my only connection to the outside world – but not for as long as I expected. Laptop Runtime Guide by UPS Capacity:

When our hospital’s critical care units nearly lost power despite having a 60 kVA UPS, we discovered most users misunderstand true UPS capacity. 60 kVA UPS Load Capacity Breakdown: Power Factor Maximum Watts Safe Operating