Electronics > Projects, Designs, and Technical Stuff

Electrolyitic Capacitor Ageing

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Glenn0010:
Hi All,

I need to calculate my expected lifetime for an Elec Cap.

I am looking at the https://www.mouser.co.uk/ProductDetail/Wurth-Elektronik/865080442004?qs=sGAEpiMZZMsh%252B1woXyUXj4jKQI6sNRw6szAjfBEpelo%3D

I can use Arrhenius’s Law to determine the liftime with regards to temprature. However what about DC operating point. Say you have a 25 V cap at 16 V. I remember hearing that that also improves life time.

Can anyone point me in the right direction

Thanks

Glenn

wraper:
Don't forget that lifetime figure is given under maximum ripple current spec. Voltage does not matter that much

MagicSmoker:

--- Quote from: Glenn0010 on February 25, 2020, 09:35:48 am ---...
I can use Arrhenius’s Law to determine the liftime with regards to temprature. However what about DC operating point. Say you have a 25 V cap at 16 V. I remember hearing that that also improves life time.

--- End quote ---

There's conflicting evidence (and mostly anecdotal at that, unfortunately) on how much longer an elko will last for a given percentage of voltage derating. Basically, there seems to be little benefit from operating at less than 75% of the WVDC rating, and if you need really a long (decades long) working life then you'd probably be better off with film capacitors.

edit - added missing "need" in last sentence.

splin:
See http://www.rubycon.co.jp/en/products/alumi/pdf/Life.pdf



[EDIT] It would be interesting to know why they only apply voltage derrating to the screw terminal capacitors - perhaps they aren't as well sealed?

[EDIT 2]: Also look at: https://www.illinoiscapacitor.com/tech-center/life-calculators.aspx

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