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# Relation between power and capacity Collection of facts and mathematics in www

Relation between power and capacity

Collection of facts and mathematics in www

With simple words
So if we examine power and capacitance together ,
we must remember , that power we get from capacitor
when dicharging , is function of dicharge time.
We can count momentary values over discharge time. ( dt = 0)
Power we got is integral over disharge time.
We must tell , that it is Pavg (0 to disharge time seconds )

KAK 14.06.2011.

All text here.....................

View attachment 159719

can i charge fastly a capacitor with a battery (3.3V, 10AH), In other words can the capacity absorbe more than 10 A in order to charge it fastly ?

yassin.kraouch;bt830 said:
can i charge fastly a capacitor with a battery (3.3V, 10AH), In other words can the capacity absorbe more than 10 A in order to charge it fastly ?

Ideal capacitor has no limitations for current, but we don´t have ideal components.
so

first must check , how high current can battery and capacitor internal wirings handle .
from datasheets max. allowed values for current

second , what is the impedance ( resistance) between battery and capacitor.
(Ri battery + Ri capacitor + R wires and connectors)

R=dU/I ....... empty capacitor .................. R= 3.3/10 = 0.33 ohm (sum of resistances for 10A charge)
... capacitor voltage 1.6V ........................ R= 1.7/10 = 0.17 ohm

If you know these resistance values you can calculate max. current between battery and capacitor.
Remember that charge current is exponential function of time ( look blog text )

Regards KAK

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