The choice between lead-acid and lithium batteries is not just an upfront cost decision — it is a 10-year total cost of ownership calculation. Here is the honest comparison.
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>Initial Cost
- Lead-acid (AGM/GEL): $150-300 per kWh installed
- Lead-acid (OPzV tubular GEL): $250-400 per kWh installed
- LiFePO4 lithium: $400-700 per kWh installed
At initial purchase, lithium costs 2-3x more per kWh than lead-acid.
10-Year Total Cost of Ownership
Example: 48V 10kWh battery system, 1 cycle/day, 10 years:
- AGM (500 cycles @ 50% DoD = 10 years): Replace once. TCO = $3,000 + $3,000 (replacement) = $6,000
- OPzV (1,200 cycles @ 80% DoD = 3.3 years per bank): Replace 2x. TCO = $4,000 x 3 = $12,000
- LiFePO4 (4,000 cycles @ 80% DoD = 11 years): No replacement. TCO = $5,000-7,000
At high cycle depth (80% DoD), lithium wins on 10-year TCO. At moderate cycling (50% DoD), OPzV can match lithium TCO at lower upfront cost.
Other Cost Factors
- Battery monitoring: Lithium (included) vs lead-acid (additional cost)
- Installation complexity: Lithium (simpler, lighter) vs lead-acid (heavier, more cables)
- Replacement cost: Lead-acid cheaper per replacement cycle
When Lead-Acid Wins
- Budget-constrained projects with moderate cycling
- Hot climates (above 35C) where lithium degrades rapidly
- Projects with 5-year payback periods or less
- Long-term fixed installations where battery replacement is not disruptive
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