1,500VA UPS runtime by load
| Equipment | Load | Runtime | UPS load |
|---|---|---|---|
| Router + modem | 20 W | 8h 25m | 2% |
| Router, modem + 2 cameras | 50 W | 2h 48m | 6% |
| Laptop + router | 100 W | 1h 13m | 11% |
| Office PC + monitor | 150 W | 45m | 17% |
| NVR with 8 cameras | 200 W | 32m | 22% |
| Desktop PC + 2 monitors | 300 W | 20m | 33% |
| Gaming PC (light load) | 450 W | 12m | 50% |
| Gaming PC (gaming) | 600 W | 9m | 67% |
| Small server rack | 900 W | 5m | 100% |
Estimates for new batteries at 25 °C and 90% inverter efficiency, using Peukert's law (k = 1.2). Battery packs vary by brand: check yours and enter it in the calculator. Batteries older than 3 years can deliver half of this.
Frequently asked questions
How long will a 1,500VA UPS run a computer?
About 45m for an office PC with a monitor (150 W) and 20m for a desktop with two monitors (300 W).
Why does half the load give more than double the runtime?
Lead-acid batteries deliver less of their rated capacity at high current (Peukert effect). At light loads you get close to the full Wh; at heavy loads much less.
How much load can a 1,500VA UPS take?
Its rating is about 900 W. Keep the load under 80% (720 W) so the inverter and batteries are not stressed.