Calculate UPS Battery Runtimes

UPS Battery Runtime Equation:

\[ \text{Runtime (hours)} = \frac{\text{Battery Capacity (Ah)} \times \text{Battery Voltage (V)} \times \text{Number of Batteries} \times \text{Efficiency}}{\text{Load Power (W)}} \]

Battery Capacity:

Battery Voltage:

Number of Batteries:

units

Efficiency:

decimal

Load Power:

Estimated Runtime:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is UPS Battery Runtime?

UPS battery runtime is the estimated duration a UPS (Uninterruptible Power Supply) system can power connected equipment during a power outage, based on battery capacity and power consumption.

2. How Does the Calculator Work?

The calculator uses the UPS runtime equation:

\[ \text{Runtime} = \frac{\text{Capacity} \times \text{Voltage} \times \text{Batteries} \times \text{Efficiency}}{\text{Load}} \]

Where:

Capacity — Battery capacity in amp-hours (Ah)
Voltage — Battery voltage (V)
Batteries — Number of batteries in the system
Efficiency — System efficiency (typically 0.8-0.95)
Load — Power consumption of connected equipment (W)

Explanation: The equation calculates total battery energy (Wh) and divides by load power to determine runtime.

3. Importance of Runtime Calculation

Details: Accurate runtime estimation helps ensure critical equipment remains powered during outages and assists in proper UPS system sizing.

4. Using the Calculator

Tips: Enter battery specifications from manufacturer datasheet, measure actual load power, and use typical efficiency of 0.9 for most UPS systems.

5. Frequently Asked Questions (FAQ)

Q1: What's typical efficiency for UPS systems?
A: Most UPS systems have 85-95% efficiency. Online UPS are typically more efficient than line-interactive models.

Q2: How accurate are these estimates?
A: Estimates are theoretical maximums. Actual runtime may be 10-20% less due to aging batteries and environmental factors.

Q3: Should I derate battery capacity?
A: For lead-acid batteries, consider derating capacity by 20% for conservative estimates, especially for older batteries.

Q4: What if my load varies?
A: Use the highest expected load for worst-case scenario planning, or calculate runtimes for different load levels.

Q5: How does battery type affect runtime?
A: Lithium batteries typically maintain voltage better than lead-acid, potentially providing slightly longer runtime at similar capacities.