1. What is Battery Capacity?

Battery capacity is the amount of energy a battery can store, typically measured in ampere-hours (Ah). This calculator helps determine the battery capacity needed to power your home for a specific duration during outages.

2. How Does the Calculator Work?

The calculator uses the battery capacity formula:

Where:

• Load Power — Total wattage of all devices you want to power
• Backup Time — Hours of runtime needed during outage
• Battery Voltage — System voltage (typically 12V, 24V, or 48V)
• Depth of Discharge — Fraction of battery capacity that can be safely used (typically 0.5-0.8)
• Efficiency — System efficiency accounting for losses (typically 0.85-0.95)

3. Importance of Proper Sizing

Details: Correct battery sizing ensures your backup system can handle your power needs without over-discharging batteries, which can reduce their lifespan.

4. Using the Calculator

Tips:

• Calculate total wattage of all essential devices
• Determine how many hours you need backup power
• Use manufacturer specs for your battery system's voltage
• Typical DoD is 50-80% for lead-acid, 80-90% for lithium
• System efficiency is typically 85-95%

5. Frequently Asked Questions (FAQ)

Q1: How do I calculate my total load power?
A: Add up the wattage of all devices you want to power simultaneously. Check appliance labels or use a wattmeter.

Q2: What's a typical depth of discharge?
A: 50% for lead-acid (extend battery life), 80%+ for lithium batteries.

Q3: Why include efficiency?
A: Accounts for losses in inverters, wiring, and battery charging/discharging.

Q4: Can I use this for solar systems?
A: Yes, this calculates battery needs regardless of charging method.

Q5: How do I convert Ah to kWh?
A: Multiply Ah by battery voltage and divide by 1000 (kWh = Ah × V / 1000).