> I need help with the calculation
> of the time of charge and discharge
> for a BackUp capacitor 0,1 uF 5,5 V

        Well, off the top of my head this should be enough for you:

Q=CV (where Q = charge in columbs, C is capacitance in Farads, V is voltage
across the cap)
I=Q/S (where I = current drawn, Q/S is columbs per second)

These calcs are a little rough since there are other things going on (ESR
will have an effect depending on your current draw, I doubt it though unless
you draw relatively large currents). There is also leakage to deal with. But
this should be enough to start. TTYL

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