How long will a 1000 VA UPS last?
A 1000VA UPS typically provides backup power for 10–60 minutes, depending on connected load and battery capacity. For example, a 1000VA/600W UPS with a 12V 9Ah battery lasts ~15 minutes at full load but extends to ~45 minutes for a 300W load. Runtime decreases exponentially as power demand increases—halving the load roughly triples uptime.
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What factors determine UPS runtime?
Battery capacity and load wattage are primary determinants. A 1000VA UPS with a 12V 7Ah battery supports 300W devices for ~20 minutes, while a 12V 18Ah model extends this to ~50 minutes. Pro Tip: Prioritize UPS units with swappable batteries for runtime customization.
Runtime follows Ohm’s Law: Energy (Wh) = Voltage × Amp-hours. A 12V 9Ah battery stores 108Wh. At 300W (25A draw), theoretical runtime is 108Wh ÷ 300W = 0.36 hours (22 minutes), but inefficiencies reduce this to ~18 minutes. For perspective, powering a 50W modem/router combo could yield 2+ hours. Always derate manufacturer specs by 20% for real-world conditions.
How does load percentage affect runtime?
Exponential decay governs UPS runtime—50% load triples uptime vs. full load. A 1000VA UPS rated for 10 minutes at 600W lasts ~30 minutes at 200W. Pro Tip: Use energy-efficient devices to maximize backup duration during outages.
| Load (W) | 300W | 600W |
|---|---|---|
| 12V 7Ah | 18 min | 6 min |
| 12V 18Ah | 48 min | 15 min |
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FAQs
Only if the UPS supports expansion ports. Unauthorized parallel connections risk inverter damage due to voltage mismatches.
Why does my UPS die faster than advertised?
Aged batteries lose 20–40% capacity after 2–3 years. Test batteries biannually and replace when runtime drops below 70% of original specs.