Battery Technologies Compared
Energy storage is the cornerstone of reliable solar systems. Two dominant technologies serve the market: Lithium Iron Phosphate (LiFePO4) and Lead-Acid (Flooded, AGM, Gel).
LiFePO4 Advantages
- Cycle life: 3,500-6,000 cycles at 80% DoD
- Usable capacity: 80-100% DoD
- Weight: ~1/3 of equivalent lead-acid
- Maintenance: Zero
- Efficiency: 95-98% round-trip
Lead-Acid Characteristics
- Cycle life: 500-1,200 cycles at 50% DoD
- Usable capacity: 30-50% DoD recommended
- Weight: Heavy (30-40 Wh/kg)
- Maintenance: Regular watering (flooded)
- Efficiency: 75-85% round-trip
Battery Sizing
Battery capacity (Wh) = Daily Load (Wh) × Autonomy Days ÷ (DoD × System Voltage × Efficiency). For a typical home consuming 10 kWh/day with 2 days of autonomy at 48V: 10,000 × 2 ÷ (0.8 × 48 × 0.95) ≈ 550 Ah.