How long will 1500VA UPS last?
A 1500VA UPS runtime depends on battery capacity and connected load. At full 1500VA load with standard lead-acid batteries (24V/100Ah), expect 10–25 minutes. For 50% load (750VA), runtime extends to 30–60 minutes. Lithium-ion batteries can triple these durations. Pro Tip: Use the formula Runtime ≈ (Battery Ah × Voltage × Efficiency) ÷ Load Watts for precise estimates, accounting for 85–90% inverter efficiency.
What is UPS Power and How Does It Protect Your Electronics?
What factors determine UPS runtime?
Key variables include battery capacity (Ah), system voltage (12V/24V/48V), load percentage, and battery chemistry. For example, a 24V/100Ah lead-acid battery bank supporting 750W load provides ≈1.6 hours (96 mins) using the formula: (100Ah×24V×0.85)/750W. Transitionally, while capacity matters, real-world performance degrades 20% annually due to sulfation.
How does load affect 1500VA UPS duration?
Load-to-runtime relationship follows inverse proportionality. Cutting load from 1500VA to 750VA quadruples runtime (theoretical) but practical gains are 3× due to fixed overheads like cooling fans. Practically speaking, a 1500VA UPS with 48V/200Ah batteries achieves:
| Load (VA) | Lead-Acid | LiFePO4 |
|---|---|---|
| 1500 | 15 mins | 45 mins |
| 750 | 50 mins | 2.5 hrs |
Transitionally, lithium batteries maintain voltage better under high loads—why they outperform lead-acid by 200–300% in sudden power draws.
Battery Expert Insight
FAQs
Yes, via parallel battery banks. Adding 24V/100Ah modules doubles runtime—but ensure charge controllers support expanded capacity. Overloading circuits causes 15–20% efficiency losses.
Why does my UPS die faster than specs claim?
Battery aging (30% capacity loss after 2 years) and high ambient temperatures (above 25°C reduces lifespan 50%) are primary culprits. Recalibrate runtime estimates annually.