The life of an electrolytic capacitor is reached when the electrolytic solution in it escapes due to self-heating. The amount of electrolyte is called capacitance, and the life is when it is reduced by 20% from the time of shipment.
The life of an electrolytic capacitor is the life due to evaporation of the electrolytic solution, and is calculated according to Arrhenius’s 10 ° C rule.
The rule of thumb is that if the surface temperature of an electrolytic capacitor is lowered by 10 ° C, the life will be doubled, and if it is raised by 10 ° C, the life will be halved.
There is “rubber” that seals the lead root of the electrolytic capacitor so that the electrolytic solution does not leak. Rubber is also a deteriorated part, and as deterioration progresses, the electrolytic solution leaks along the leads and causes a short circuit on the board pattern.
It’s not a rubber problem, but the electrolyte of “quaternary salts” that was used in the latter half of the 1980s leaked out and caused a lot of problems that shorted the pattern on the board. This is because the quaternary salts is strongly alkaline and corrosive, making it difficult to seal, and it broke the lead wire and the rubber of the seal, causing liquid leakage. Currently, quaternary salts is not used, but I remember that the electrical industry was in a turmoil at that time and it took several years to recover it.
Returning to the story, according to electrolytic capacitor manufacturers, rubber is calculated for a long time when the ambient temperature is low, but when the ambient temperature is high, it seems that the actual life is about 10 to 15 years. Therefore, even if the life of the electrolytic capacitor is calculated according to Arrhenius’s 10 ° C rule and is 10 years or more, the life is guaranteed only up to 10 years when the deterioration of the sealing rubber is taken into consideration.
Considering the life of this sealing rubber of 10 years, some manufacturers cut the calculated electrolytic capacitor life of 10 years or more, and some manufacturers say, “The life of the sealing rubber is not taken into consideration.” Also, please note that it may be mixed even within the manufacturer depending on the development time and development location.
In addition, the “electrical capacitor life” on this site is a calculated value based on the Arrhenius 10 ° C rule when the ambient temperature is 40 ° C and the load factor is 80%. The life of the sealing rubber is omitted for easy comparison.