Electrolytic cap lifetime

[Aentons]

Does buying Electrolytic caps with a higher voltage rating than required help extend the lifetime? I haven't looked at many de-rating charts so I'm not sure if they address this specific question.

For instance, if I need a cap rated at 16v. All other factors being equal, which would be the better choice? A 5000hr rated 16v cap, or a 2000hr rated 50v cap?

[cooder]

I don't know an answer to that specific question but I'm also wondering about the life expectancy and how reliable the manufacturer specs for expected lifetime really are... many cheapo manufacturers of stuff grossly overstate, make up or just take stuff out of thin air at times me thinks?!?

[Aentons]

I know temperature plays a big part in failure, but my suspicion is that the temperature plays into the voltage fluxuations.

This article says:
https://passive-components.eu/capacitors-voltage-and-temperature-derating-and-category-concepts/
"voltage derating is the most effective way to increase life time"

...so it makes it sound like higher voltage rating is more important than rated hours even if the application is within the rating best practice guidelines.

just looking for some real-world type confirmation or experiences

[mauman]

The "lifetime rating" such as 5,000 or 10,000 hours is a minimum for operation time at the rated specs (voltage, temperature, ripple, etc.) without the capacitance value changing more than a specified amount (such as 20%.)  Doesn't mean it will start leaking at that point.  And if you significantly derate the cap by selecting one with a higher voltage rating, operating it a lower than rated temp, etc, lifetime can increase by a lot.   However, most manufacturers recommend a 15 year lifetime (calendar, not operating time) due to deterioration of the sealants.   So EL caps do degrade over time, but you can slow it down, just check them after 15 years...    Mike