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Double Layer Supercapacitor life.

Former Member

Hellow Everyone.

I am planning to use two supercapacitors 4.7F, 2.7V, 1-ohm, Type JUWT1475MPDJUWT1475MPD, NICHICON make for backup supply in one of my products. Can some one help me to give me some idea about the expected life time ( when capacitor requires replacement)?

Conditions are as below:

1. Two capacitors in series charged with 5.5V SMPS.

2. Temperature: 50 deg C

3. Humidity: 60%

4. Capacitor remains charged through SMPS, Shall be called upon to feed 50mA load on mains failure for one minute in a year or so.

 

Any feedback shall highly be appreciated.

  • 0

    Welcome to element14.

     

    Reading the datasheet

     

    It states that the caps should get 1000 hrs @ 70 deg C.

    The life expectancy of supercapacitors is identical to aluminum electrolytic

    capacitors. The life of supercapacitors will double for every 10°C decrease in

    the ambient temperature the capacitors are operated in. Supercapacitors

    operated at room temperature can have life expectancies of several years

    compared to operating the capacitors at their maximum rated temperature.

     

    L2=L1*2^X    X=(Tm-Ta)/2

     

    L1= Load life rating of the super capacitor.

    L2= expected life at operating condition.

    Tm= Maximum temperature rating of the supercapacitor.

    Ta= Ambient temperature the supercapacitor is going to be exposed to in the

    application.

     

    For your caps:

    X = (70-50)/2 = 10

    L2 = (1000hrs)*2^10 = 1024000

     

     

     

    Since you are running the caps a little higher than the rated voltage, but at a lower temp, you will most likely experience component degradation.

     

    You might want to change your operating voltage slightly. Always factor in about 30% error.

     

    Cabe

    http://twitter.com/Cabe_e14

  • 0 in reply to Catwell

    My sincere thanks to Mr. Atwell for sparing out some time to reply my question.

    I am reducing the SMPS supply to 5.2V as advised. However I was looking for some idea about the total life (not load life). In my application capacitors shall be called upon to provide backup hardly once or twice in a year, that too for the duration of 10 seconds only.

    Hope you will throw some light on this aspect.

  • 0 in reply to Former Member

    Hi

     

    I doubt you will get a better answer than that which Cabe gave. Suffice to say that a Lithium rechargeable would give a max of around 500 cycles and the SuperCap maybe upto 100,000 cycles..

     

    Therefore your SuperCaps will most likely outlive the products effective life.