Selection Guide
Supercapacitor Lifetime: How Temperature and Voltage Affect Longevity
How temperature and voltage drive supercapacitor aging, how end-of-life is defined, and how to estimate service life for high-temperature designs.
Updated 2026-10-28 · 9 min read
The challenge
Supercapacitors do not usually fail suddenly; they age — capacitance decreases and ESR increases. A design must still work at end of life.
How end of life is defined
Manufacturers typically define end of life as a capacitance loss (e.g. −20% or −30%) and/or ESR increase (e.g. 2× initial) after a load-life test at rated voltage and maximum temperature.
Temperature
A commonly cited approximation is that life roughly doubles for every 10 °C reduction in cell temperature. Cell temperature includes self-heating from ESR losses.
Voltage
Lower working voltage slows electrolyte degradation. Derating by a few hundred millivolts per cell can significantly extend life — quantify with the manufacturer’s data.
Estimating life (approximation)
L ≈ L_rated · 2^((T_rated − T_use)/10)
This is a first-order estimate only; it does not replace the manufacturer’s life curves or qualification testing.
Low-temperature operation
Cold reduces capacitance modestly and increases ESR significantly. For −40 °C operation, size ESR drop at the cold corner.
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