1. What is the APC Battery Runtime Calculation?

The APC battery runtime calculation estimates how long a UPS (Uninterruptible Power Supply) will last during a power outage based on battery capacity, voltage, efficiency, and the actual load being powered.

2. How Does the Calculator Work?

The calculator uses the runtime equation:

Where:

• \( \text{Measured Ah} \) — Battery capacity in amp-hours
• \( V \) — Battery voltage
• \( \text{Eff} \) — UPS efficiency (typically 0.85-0.95)
• \( \text{Actual Load W} \) — Power consumption of connected equipment

Explanation: The equation calculates how long the battery can supply the required power based on its capacity and the UPS's conversion efficiency.

3. Importance of Runtime Calculation

Details: Accurate runtime estimation helps determine if your UPS can provide sufficient backup time for critical equipment during power outages and when batteries need replacement.

4. Using the Calculator

Tips: Enter measured battery capacity in Ah, battery voltage, UPS efficiency (default 0.85), and actual load in watts. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure battery Ah?
A: Use a battery tester or discharge test. For new batteries, refer to manufacturer specifications.

Q2: What's typical UPS efficiency?
A: Most UPS systems have 85-95% efficiency. Line-interactive UPS typically has 85-90%, while double-conversion has 90-95%.

Q3: Why is my actual runtime shorter than calculated?
A: Possible causes include aging batteries, higher ambient temperature, or additional hidden loads on the UPS.

Q4: How often should I test my UPS batteries?
A: Recommended every 3-6 months, with a full discharge test annually to verify capacity.

Q5: When should I replace my UPS batteries?
A: When capacity drops below 80% of original or runtime becomes insufficient for your needs (typically every 3-5 years).