BATTERY CHEMISTRY DECISION
48V / 1000Ah · 20-YEAR HORIZON
Normalized comparison · daily cycling · replacements included
NORMALIZED BREAKDOWN
All rows scaled to 48 kWh nominal so the comparison is apples-to-apples
| Chemistry | Upfront (€) | Usable kWh | Charge Efficiency | Cycles @ DoD | Years / Bank | Banks in 20 yr | 20-yr Total (€) | € / USABLE AH |
|---|---|---|---|---|---|---|---|---|
| LiFePO4 WINNER | 8,955 | 43.2 @ 90% | 92–96% | 6,000 | 16.4 | 1.2 | ~9,000/15YR | €10.6 |
| NiFe† ROBUST | 16,000 | 38.4 @ 80% | 65% < | 12,000 | 32.9 | 1 | ~16,000 | €27.3 |
| Gel MIDDLE | 8,417 | 28.8 @ 60% | 80–85%< | 1,800 | 4.9 | 4.1 | ~34,500 | €14.0 |
| Flooded TRAP | 4,560 | 24.0 @ 50% | 75–85% | 800 | 2.2 | 9.1 | ~57,000 | €9.1 |
† NiFe pricing is an estimate derived from €164/cell sourcing data — verify locally before committing. “Banks in 20 yr” counts replacements over the full horizon at the stated depth of discharge.
20-YEAR TOTAL COST
Lower is better · scaled against the worst performer (Flooded, ~€57,000)
Includes upfront purchase plus every replacement bank needed to survive 20 years of daily cycling.
COST PER USABLE AMP-HOUR OVER 20 YEARS
Over 20 years · the metric that exposes cheap-sticker chemistries
Note the inversion: flooded is the cheapest per usable Ah at purchase (€9.1) and the most expensive over 20 years (€83.2). Sticker price is not lifetime cost.
RECAP
Three answers, condensed
- PV estimate: 12× 400W panels (4.8 kW) wired as 6 series-pairs is a solid starting point. That covers LiFePO4 comfortably and gives cloudy-day buffer. For NiFe you'd want 14–16 panels to offset the 65% round-trip penalty.
- Usable kWh: LiFePO4 wins (43.2 vs 38.4 kWh). NiFe's advantage is longevity, abuse tolerance and less electronics needed (No BMS, less RF noise).
- Charge efficiency: the percentage of energy that survives the in-and-out journey. NiFe burns roughly 35% as heat; LiFePO4 burns about 6%.