1. What is Access Control Battery Backup?

The battery backup time calculation determines how long an access control system can operate during a power outage based on battery capacity, voltage, and system power consumption.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• Battery Capacity — The total amp-hour rating of the battery
• Voltage — The system voltage (typically 12V or 24V for access control)
• Access Control Load — The total power consumption of the system in watts

Explanation: The equation converts battery capacity to watt-hours (Ah × V = Wh) then divides by power consumption to get runtime in hours.

3. Importance of Backup Time Calculation

Details: Proper backup time calculation ensures access control systems remain operational during power outages, maintaining security and functionality.

4. Using the Calculator

Tips: Enter battery capacity in amp-hours (Ah), system voltage in volts (V), and total access control system load in watts (W). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical battery capacity for access control?
A: Common capacities range from 7Ah to 18Ah for small systems, with larger installations using multiple batteries.

Q2: What voltage do most access control systems use?
A: Most systems operate at 12V DC, though some larger systems use 24V DC.

Q3: How do I measure my access control system's load?
A: Check power supply specifications or measure current draw with a multimeter and multiply by voltage (P = V × I).

Q4: Should I derate the battery capacity?
A: Yes, consider reducing capacity by 20-30% for lead-acid batteries to account for aging and efficiency losses.

Q5: What affects actual backup time?
A: Temperature, battery age, discharge rate, and whether the system is in alarm state (higher power draw) all affect runtime.