Home Battery Cost Per Cycle Calculator
Payback calculators tell you when a battery breaks even on your power bill. This tells you what the battery itself actually costs every time it charges and discharges over its warranty - a different and more honest number. Nothing uploaded.
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Learn more: cost per cycle versus cost per kWh
How the cost per cycle is calculated
Cost per cycle is the battery price divided by its rated cycle life. A $4,000 LiFePO4 battery rated for 6,000 cycles costs $4,000 / 6,000, or $0.67 per cycle. A lead-acid battery at $800 rated for 500 cycles costs $1.60 per cycle, about 2.4 times as much, even though it costs a fifth of the price up front.
The calculator does not ask for capacity, so compare batteries of the same usable size. A larger battery delivers more energy per cycle, and a cost per cycle on its own would ignore that.
Warranty years and real usage
The default cycles per year spreads the rated cycle life across the warranty period, capped at one cycle a day (365). For the 10 year, 6,000 cycle example that would be 600 a year, so the cap applies. Cycled once a day, the $4,000 battery costs about $243 a year in cycle terms and would take roughly 16 years to reach 6,000 cycles, longer than the warranty.
The yearly cost at usage is cost per cycle times the cycles you expect each year, so a battery cycled less than daily costs less per year. With the default $10,000 price the figures are $1.67 per cycle and $608 a year at 365 cycles, against $1,000 a year if you only divide the price by the 10 warranty years.
FAQ
Why would anyone still buy lead-acid?
The upfront price can decide it when budget is the limit, and a system that cycles rarely may never use up its rated cycles. Compare the cost per cycle with how often you will really cycle it.
Does depth of discharge affect the cost per cycle?
Cycle life ratings are tied to a depth of discharge, which the manufacturer states. Check what your rating assumes, because a different depth of discharge can change how many cycles you actually get.
Is cost per cycle the only number that matters?
No. Usable capacity, warranty terms, temperature limits and safety also matter. Cost per cycle works best for a battery that cycles daily and says little about one that mostly sits idle.