How to use the Home Backup Battery Sizing Calculator
The Formula
Wh needed = (load W × hours) ÷ inverter efficiency. Bank Wh = Wh needed ÷ (DoD ÷ 100). Bank Ah = bank Wh ÷ system voltage.
Practical Example
Consider 10–20% extra for battery aging and cold weather. Lithium often allows 80–90% DoD; lead-acid is typically 50%.
About Home Backup Battery Sizing Calculator
Sizing formula
Wh needed = (load W × hours) ÷ inverter efficiency. Bank Wh = Wh needed ÷ (DoD ÷ 100). Bank Ah = bank Wh ÷ system voltage.
Add margin
Consider 10–20% extra for battery aging and cold weather. Lithium often allows 80–90% DoD; lead-acid is typically 50%.
Frequently asked questions
Q: Is this for whole house? A: Use essential circuits only—fridge, lights, internet. Q: Include solar? A: This is storage-only; add solar yield separately.