LiFePO4 vs Lead-Acid: 10-Year Total Cost of Ownership
Lead-acid wins the first receipt and loses the next ten years. Here is the math on a 10kWh system cycled every day, with the four cost lines separated so you can plug in your own numbers.
The scenario
10kWh discharged daily, 365 days a year, for 10 years. That is 3,650 full cycles. LiFePO4 runs at 90% depth of discharge. Lead-acid runs at 50% depth of discharge, so you size it at 20kWh rated to deliver the same 10kWh usable.
Line 1: replacements
LiFePO4 rated cycle life sits at 4,000-6,000 cycles at 80% depth of discharge. At 3,650 cycles over a decade, one unit covers the whole period. Lead-acid floods at 500 cycles, AGM at 600, gel at 700. Divide 3,650 by those and you buy 6-8 replacements. At $1,200-1,800 each, that is $6,000-14,400 in swap costs alone.
Line 2: energy lost to inefficiency
LiFePO4 round-trip efficiency runs 95-98%. Lead-acid runs 70-85%. On 10kWh/day the gap is 1.3-2.8kWh lost to heat every day. Over 10 years that is 4,700-10,200 kWh you pay to generate and never use. At $0.15/kWh that bills to $700-1,500.
Line 3: maintenance labor
Flooded lead-acid needs monthly water top-ups, terminal cleaning, and equalization charges. AGM and gel need less but still want terminal and voltage checks. Put a rate on the hours. Most operators skip the labor and accept shorter life, which pushes Line 1 costs higher. Budget $500-1,000 over 10 years if you do it right.
Line 4: the purchase price
LiFePO4 10kWh: $2,000-3,000. Lead-acid 20kWh rated: $1,200-1,800. The lead-acid unit costs less to buy and three to eight times more to own.
The 10-year totals
| Cost line (10 years) | LiFePO4 (10kWh) | Lead-Acid (20kWh rated) |
|---|---|---|
| Initial purchase | $2,000 – $3,000 | $1,200 – $1,800 |
| Replacements | 0 | $6,000 – $14,400 |
| Energy lost | $200 | $700 – $1,500 |
| Maintenance | $0 | $500 – $1,000 |
| 10-year total | $2,200 – $3,200 | $9,200 – $19,700 |
Where lead-acid still wins
Three cases keep lead-acid alive. Upfront cash is the only constraint and you can't finance the gap. Temperatures sit below -20°C where LiFePO4 needs a heater. The system cycles 20-30 times a year, not daily, so the replacement line never hits. Outside those, the TCO math favors lithium by 3-6x.
Run your own numbers
Take your daily kWh, your local electricity rate, and your supplier's quote for both chemistries. Apply the four lines above. The purchase price is the smallest number on the page. The replacement line decides the outcome.
Get a TCO quote for your load
Tell us your daily kWh and cycle pattern. We return LiFePO4 vs lead-acid TCO side by side with our factory-direct pricing.
Request TCO Quote →Full chemistry comparison: LiFePO4 vs Lead-Acid Complete Comparison. Last updated: August 2026.