Battery chemistry & storage
Pick a chemistry and time horizon. See how much projected capacity remains under four different usage patterns, from daily cycling to backup-only.
How it works
Step 1
Each chemistry has different calendar and cycle aging rates, which sets how sensitive the results are to usage pattern, covered in more detail in the calendar aging calculator.
Step 2
A longer horizon widens the gap between usage patterns, since the cycle-based portion of aging compounds over more years.
Step 3
Match your actual cycling frequency to the closest pattern rather than assuming daily use applies to every system. The calendar aging calculator lets you enter an exact cycling frequency if none of these four fit well.
Every battery experiences calendar aging on a fixed timeline regardless of use, but cycle-based aging only accumulates in proportion to actual charge and discharge activity. A lightly used battery is closer to pure calendar aging, while a heavily cycled battery experiences both effects stacked together, a distinction NREL's energy storage research treats as two separate aging mechanisms rather than one combined rate, which is why usage pattern alone can produce meaningfully different outcomes from an identical starting battery.
Slowing degradation by cycling a battery less only makes sense if reduced use is actually compatible with what you need it to do, since a battery that never gets used isn't providing any value either. Compare this tool's numbers against your actual required usage pattern, covered separately in the daily cycling and backup only use comparisons, rather than trying to minimize cycling for its own sake. A system doing time of use arbitrage is a good example of daily cycling that's earning its keep despite the faster degradation curve.
Over a short time horizon, calendar aging dominates regardless of usage pattern, so the four rows in this comparison look fairly similar. Extend the horizon out further and the cycle-based component compounds more for the frequently cycled patterns, widening the gap between daily use and backup-only use considerably, the same widening curve the battery lifespan estimator shows when it projects a single usage pattern out year by year instead of comparing several at once.
If you want to see year-by-year detail rather than just an endpoint, the capacity over time calculator generates a full table for a single usage pattern of your choosing. This same usage-pattern-driven degradation question comes up at grid scale too, where the DOE's Office of Electricity factors duty cycle into how it evaluates storage system performance over time.
Questions
For the same LFP battery over 10 years, daily cycling might leave around 73% of original capacity, while backup-only use with occasional cycling might leave closer to 90%, using the identical chemistry and starting battery. Usage pattern alone can account for a meaningful swing in how much capacity remains after the same number of years.
Calendar aging happens on a fixed timeline no matter how the battery is used, but cycle-based aging adds on top of that baseline in proportion to how often the battery is charged and discharged. A battery cycled daily accumulates both effects, while a lightly cycled battery is closer to calendar aging alone.
Only if reduced cycling is actually compatible with what you need the battery to do, since underusing a battery to preserve capacity defeats the purpose of buying storage in the first place. This tool is meant to help you understand what to expect from your real usage pattern, not to suggest cycling less than your situation requires.
Most solar self-consumption and time-of-use arbitrage systems land close to the daily cycling pattern, since the battery charges from solar and discharges most days regardless of weather. A backup-only pattern applies more to a generator-replacement system that mostly sits idle waiting for an outage.