Battery Bank Capacity & Chemistry Sizer

Size usable and nominal storage in Ah and kWh for LiFePO4, AGM, or Gel.

Daily Energy Consumption (Wh) Total daily Watt-Hours (from load audit).

System Voltage Nominal battery bank voltage.

Days of Autonomy (No Sun Backup) Days system must run during rain or heavy clouds (2.0 days recommended).

Battery Chemistry Determines safe maximum Depth of Discharge.

REQUIRED BATTERY STORAGE

250 Ah Bank

Total nominal energy: 3.0 kWh (80% DoD).

Usable Energy

2,400 Wh

200 Ah usable draw

Expected Longevity

3,500 – 6,000 cycles

10 – 15 years

Do not charge below 0°C (32°F) unless equipped with internal heating elements or low-temp BMS cutoff.

Engineering Scope & Formulas

Supports LiFePO4, AGM, Flooded Lead-Acid, and Gel batteries from 12V to 48V systems with commercial module counts.

Required Wh = (Daily Wh × Autonomy Days) ÷ Depth of Discharge (DoD); Required Ah = Required Wh ÷ System Voltage

Deep dive into the electrical theory, wire gauge charts, and thermal derating behind this calculator in our field guide:
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