How long can 1000VA UPS last?
1000VA UPS runtime depends on battery capacity (Ah), load power (W), and system voltage. A standard 1000VA UPS with 12V 100Ah battery and 600W load (60% VA) lasts ≈2 hours. Runtime halves with doubled load (300W ≈4h). Pro Tip: Use formula: (Battery Ah × Voltage) ÷ Load Watts = Runtime (hours).
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What factors determine 1000VA UPS runtime?
Three key variables control UPS duration: battery bank size, connected load, and system efficiency. Higher Ah batteries and lower wattage devices extend uptime exponentially.
Practically speaking, a 1000VA/600W UPS with 48V 50Ah lithium batteries stores 2.4kWh (48×50). Divided by 600W load, that’s 4 hours runtime. But what happens if you add another battery bank? Doubling capacity to 100Ah pushes runtime to 8 hours. Warning: Never mix old/new batteries – cell imbalance causes premature failure. For example, data centers often use parallel battery cabinets with 1000VA UPS systems to achieve 30+ minute runtime for critical servers.
How does load affect 1000VA UPS duration?
Load power inversely impacts runtime – 500W devices get 2× longer backup than 1000W loads. VA-to-Watt conversion (typically ×0.6-0.9 PF) determines real energy draw.
Let’s break it down: A 1000VA UPS assuming 0.8 power factor delivers 800W. With 24V 200Ah batteries (4.8kWh):
• 400W load: 12 hours
• 800W load: 6 hours
• 1200W overload: Shuts down immediately
Beyond basic math, consider surge currents – motor-driven devices like AC units may momentarily draw 3× rated power during startup. Pro Tip: Size UPS capacity to handle peak loads, not just nominal ratings.
| Load (W) | 600Ah System | 1200Ah System |
|---|---|---|
| 300 | 19.2h | 38.4h |
| 600 | 9.6h | 19.2h |
| 900 | 6.4h | 12.8h |
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FAQs
Yes – add parallel battery packs (same voltage/Ah) or replace existing ones with higher capacity. Each 100Ah increase adds ≈1 hour per 600W load.
Why does my UPS die faster than calculated?
Aging batteries (capacity fade), high ambient temps (＞25°C cuts life 50%), or incorrect PF assumptions. Test actual load with clamp meter annually.
Is 1 hour sufficient for home UPS?
For PCs/TVs: Yes. For sump pumps/medical devices: No – size for 8-24h backup. Pro Tip: Hybrid systems with solar integration provide indefinite runtime.