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Compare the true long-term cost of LiFePO4 vs lead-acid batteries for dealers, wholesalers, RV sellers, and solar installers. This calculator goes beyond purchase price: it accounts for usable energy, cycle life, depth of discharge, round-trip efficiency, calendar aging, and replacement cycles over time.
LiFePO4 Battery
Lead-Acid Battery
Cost comparison
| LiFePO4 | Lead-Acid | |
|---|---|---|
| Initial purchase cost | ||
| Usable energy per cycle | ||
| Lifetime delivered energy | ||
| Cost per lifetime delivered kWh | ||
| Replacement frequency | ||
| Total cost over 5 years | ||
| Total cost over 10 years | ||
| Break-even point | ||
Cost per lifetime kWh (USD)
Cumulative battery cost over 15 years (USD)
The step chart includes replacement purchases when each battery’s effective service life is exhausted. Break-even conclusions apply to this 15-year observation window only and do not guarantee continued advantage beyond year 15.
Using these results in customer quotes
For dealers, wholesalers & installers: lead with cost per lifetime delivered kWh when quoting against lead-acid competitors — it reframes the conversation from sticker price to ownership cost. Use the 5/10-year totals for replacement-budget planning, and the break-even year to answer “when does lithium pay for itself?”
Always base the inputs on your actual supplier quotes and the customer’s real duty cycle, and weigh initial purchase cost, long-term replacement cost, actual operating conditions, and warranty & quality differences between specific products. These figures are planning estimates, not guaranteed savings.
Ready to switch to LiFePO4?
Dealer and wholesale pricing available. OEM/ODM customization supported.
How the calculation works
All formulas are open — no hidden assumptions:
- Annual energy throughput is the energy your application actually consumes at the load per year — after efficiency losses. The same value applies to both batteries.
- Usable energy per cycle (kWh) = Voltage × Ah ÷ 1000 × DoD
- Energy delivered per cycle (kWh) = Usable energy × Round-trip efficiency
- Effective service life (years) = MIN(cycle life ÷ equivalent full cycles per year, calendar life). Calendar life is your planning assumption, not a predicted failure date; leave it empty for cycle-life-only modeling.
- Lifetime delivered energy (kWh) = Energy delivered per cycle × effective full cycles (capped by calendar life when entered)
- Cost per lifetime delivered kWh = Purchase price ÷ Lifetime delivered energy
- Total cost over N years = Purchase price × number of battery lives needed in N years (rounded up)
- Break-even point = the last year in which cumulative cost flips to LiFePO4's advantage (strictly cheaper — equal yearly cost does not count as savings) and stays there through year 15. Checked year by year; a single early crossing that later reverses does not qualify.
Default values are typical industry figures for reference only. Actual battery lifespan is affected by temperature, charge/discharge patterns, and cell quality. Break-even conclusions apply to the selected 15-year observation window only and do not guarantee continued advantage beyond year 15. This tool is for planning purposes and does not constitute purchasing advice.
Frequently asked questions
Why can't I just divide purchase price by cycle life?
Because a cycle of a lead-acid battery at 50% DoD delivers far less energy than a cycle of a LiFePO4 battery at 90% DoD. True cost comparison must use cost per lifetime delivered kWh, which accounts for usable energy, depth of discharge, and round-trip efficiency.
What is cost per lifetime delivered kWh?
Purchase price divided by the total energy the battery will deliver over its effective service life. It is the fairest single metric for comparing battery economics across chemistries.
How is the break-even point calculated?
The calculator builds a year-by-year cumulative cost model over 15 years, including replacements. It finds the last year where cumulative cost flips to LiFePO4's advantage and stays there through year 15. Equal yearly costs are not counted as savings, and a single early crossing that later reverses does not qualify. Results apply to the 15-year window only.
What is calendar life, and should I enter it?
Calendar life is the maximum service years you assume for planning, regardless of cycling — for example, a battery cycled lightly may still age out. It is your assumption, not a predicted failure date. Leave it empty to model cycle life only; without it, results may overestimate real service life in light-use scenarios.
Why does the calculator ask for annual energy throughput?
Replacement frequency depends on how hard the battery is cycled each year. Throughput means energy your application actually consumes at the load, after efficiency losses. The same battery lasts many years in a weekend RV but may need replacing annually in a daily-cycled solar system.
Are the default values accurate?
Defaults are typical industry reference values for illustration only — always replace them with your actual supplier quotes. Real-world battery life also depends on temperature, usage patterns, and cell quality.
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