Hi,

I'm hoping that there are some supercapacitor experts out there...!!

I've been told some conflicting information regarding the expected life of
supercaps:

Source 1:

NEC say that

"Life is defined to be expired when the capacitance is reduced to 30% of
the nominal value" and:
"Supercap life = (life in hours at To)  * [ 2 ** ( ( To - T) / a) ]"

where
To = operating temp
T = test temperature
a = some coefficient in the range of 6-7

So, e.g.:

For:

Life at To of 85 deg C = 1000h

Then, for 50 deg C and a=6

Life = 1000h * (2**((85-50)/6)) = 57017h

Source 2:
All components double their life for every 10 deg C temperature reduction.


So, source 1 suggest a doubling of life for every 6-7 deg reduction
whereas source 2 suggests the doubling is for every 10 deg.

This value of 'a' can cause quite a difference, esp. for cost sensitive
applications!

Can anyone shed more light on which claim is more realistic and/or a
reliable source of supercap information?

Best regards,
Dan Lloyd

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