Calculate required battery bank capacity in Amp-hours (Ah) and kWh from daily consumption, system voltage (12V, 24V, 48V), autonomy days and LiFePO4/AGM DoD.
Engineering Standard (IEEE 485 / IEC 61427): Battery sizing must account for inverter conversion efficiency (~90%) and maximum allowable Depth of Discharge (DoD: 85% for LiFePO4, 50% for AGM).
| Technical Parameter | Lithium Iron Phosphate (LiFePO4) | Lead-Acid AGM / Gel |
|---|---|---|
| Depth of Discharge (DoD) | 80% - 95% without cycle degradation | 50% max to prevent plate sulfation |
| Estimated service life | 3,500 to 6,000 cycles at 80% DoD | 400 to 700 cycles at 50% DoD |
| Weight per 100Ah at 12V | 11 kg - 13 kg | 28 kg - 32 kg |
| Voltage sag under heavy load | Flat discharge curve at 13.2V - 12.8V | Drops rapidly below 12.0V (Peukert effect) |
Multiply daily energy use (Wh) by required autonomy days, then divide by (System Voltage × Max Depth of Discharge DoD × Inverter Efficiency).
LiFePO4 batteries safely allow an 85%–90% Depth of Discharge (DoD) for over 4,000 cycles, whereas AGM batteries must be limited to 50% DoD.