UPS Runtime Calculator
Calculate how long your UPS (Uninterruptible Power Supply) will provide backup power to connected equipment during power outages.
UPS Runtime Results
How to Use This Calculator
- Enter your UPS battery capacity in amp-hours (Ah)
- Input the UPS battery voltage (typically 12V per battery)
- Enter the total power consumption of connected equipment
- Adjust inverter efficiency (typically 85-95%)
- Set depth of discharge limit (typically 80% for lead-acid)
- Click "Calculate UPS Runtime" to see backup duration
Finding UPS Specifications
- Battery Capacity: Check UPS manual or battery labels
- Load Power: Add up wattage of all connected devices
- Battery Configuration: Multiple batteries may be in series/parallel
Frequently Asked Questions
How accurate is this UPS runtime calculator?
The calculator provides theoretical estimates based on ideal conditions. Actual runtime may vary by 10-25% due to factors like battery age, temperature, load variations, and UPS efficiency changes under different loads. Results are most accurate for steady loads at room temperature.
What factors affect UPS runtime?
Runtime is affected by battery capacity and age, load power consumption, inverter efficiency, temperature, depth of discharge limits, and power factor of connected equipment. Higher loads significantly reduce runtime, while lower temperatures can decrease battery capacity.
How do I calculate total load power for my UPS?
Add up the power consumption of all devices connected to the UPS. Check device labels, power adapters, or use a power meter. Include computers, monitors, networking equipment, and any other connected devices. Consider that some devices may have higher startup power requirements.
What is depth of discharge and why is it important?
Depth of discharge (DoD) is the percentage of battery capacity that can be safely used. Lead-acid UPS batteries typically allow 80% DoD to maximize lifespan. Deeper discharge provides more runtime but reduces battery life. Most UPS systems automatically shut down before damaging the batteries.
How can I extend my UPS runtime?
Reduce connected load by disconnecting non-essential devices, upgrade to higher capacity batteries, add external battery packs if supported, maintain batteries properly, keep UPS in cool environment, and consider energy-efficient equipment. Regular battery replacement also maintains optimal runtime.