1. What is Whole Home Battery Backup?

A whole home battery backup system stores electrical energy to power your home during outages or when disconnected from the grid. Proper sizing is crucial to ensure your essential loads can be powered for the required duration.

2. How Does the Calculator Work?

The calculator uses the basic battery sizing formula:

Where:

• \( \text{Home kWh} \) — Your home's daily energy consumption in kilowatt-hours
• \( \text{Battery V} \) — Voltage of your battery bank (typically 12V, 24V, or 48V)
• \( \text{Ah} \) — Required battery capacity in amp-hours

Explanation: The formula converts your energy needs from kilowatt-hours to watt-hours (×1000) then divides by battery voltage to get amp-hour capacity.

3. Importance of Proper Sizing

Details: Correct battery sizing ensures your backup system can meet your energy needs without being oversized (costly) or undersized (inadequate power). Consider adding 20-30% capacity for efficiency losses and battery longevity.

4. Using the Calculator

Tips:

• Check your utility bill for average daily kWh usage
• Typical battery voltages are 12V, 24V, or 48V (higher voltages are more efficient)
• For multiple days of autonomy, multiply result by number of days

5. Frequently Asked Questions (FAQ)

Q1: How do I find my home's kWh usage?
A: Check your electricity bill - it typically shows average daily or monthly kWh consumption. Divide monthly by 30 for daily average.

Q2: What's the difference between Ah and kWh?
A: Amp-hours (Ah) measure battery capacity at a specific voltage, while kilowatt-hours (kWh) measure total energy. kWh = (Ah × V) / 1000.

Q3: Should I use 12V, 24V or 48V battery bank?
A: Higher voltages (24V or 48V) are more efficient for whole home systems as they reduce current and wiring costs. 12V is typically for small systems.

Q4: How does depth of discharge affect sizing?
A: Most batteries shouldn't be discharged 100%. For 50% depth of discharge, double the calculated Ah capacity.

Q5: What about inverter efficiency?
A: Add 10-15% to your calculated capacity to account for typical 85-90% inverter efficiency losses.