Capacitor Aging

Home Up

Below is some useful information on the shelf life and re-aging procedures for aluminum electrolytic capacitors. The information is from Cornell-Dubilier circa October 1993.


The following time limits apply to shelf life at 35C 60%RH for all styles of CDE Aluminum Electrolytic capacitors:

 1Year - Will meet initial parameters.
 3 Years - Recommend testing before use to determine if re-aging is required to meet initial parameters of DCL (leakage).
 4 Years - Re-aging is usually required before use.
 5 Years - Typically expect to meet all parameters after re-aging.
 10 Years - Typically end of useful shelf life, but subject to many variables.


  1. This re-aging procedure is performed at room temperature.
  2. Connect capacitor to a voltage source with a resistor in series. 10K ohms for 75VDC and below. 100K ohms above 75VDC.
  3. Slowly increase voltage to the rated WVDC while monitoring the charge current. Do not allow the charge current to any individual unit to exceed 1mA.
  4. After reaching full voltage, continue to apply full voltage for a minimum of 4 hours.
  5. Re-test DCL (leakage) after re-aging is complete.

Last Edited: 17 Oct 2005
By: Mike Murphy, WA4BPJ
E-mail your Comments