Battery Capacity Calculator for Solar Systems
Solar Powered Project
1 min read
Calculate solar battery capacity from daily Wh, days of autonomy, and depth of discharge. Includes a simple sizing formula for off-grid and backup systems.
Formula
Battery Wh = Daily Wh × Days of autonomy ÷ Depth of discharge
Example: 2,000Wh × 1 day ÷ 0.8 = 2,500Wh
Tips
For solar systems, usable capacity matters more than nameplate. Match your battery bank to system voltage and inverter draw so cabling and protection stay realistic.
- Li-ion often supports deeper discharge than lead-acid.
- Factor in inverter efficiency for AC loads.
- Size for critical loads first.
- Cold temperatures reduce usable capacity.
