Determining current drawn from a capacitor

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SUMMARY

The discussion focuses on estimating the current drawn from a 3000F supercapacitor using voltage drop measurements. The initial voltage (V1) is 1.100V, and after 3.5 seconds under load, the voltage (V2) drops to 1.045V. The energy calculations reveal that 177J was spent, resulting in an average power output of 50.5W. The current is accurately estimated at 47.1A using both energy and capacitor equations, confirming the validity of the approach taken.

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Artlav
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Hello.

I want to know what current i am getting out of a supercapacitor, but i have nothing to directly measure the currents in the given range with.
So i tried to determine it from the voltage drop on the cap, and i want to know if i did it right.

Given is 3000F capacitor, at initial voltage of V1=1.100V.
After being connected to the load in question for 3.5 seconds, the voltage is V2=1.045V.

Thus, the energy in the capacitor is 0.5*C*V*V.
E1=1815J
E2=1638J
Which gives spent energy of 177J.

W=J/s, so for the 3.5 seconds it was giving out 50.5W of power.
Finally, A=W/V, and average V was 1.0725V, which gives 47.1A of current.

Is that a correct way of current estimation?
 
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You can also use a capacitor equation.

C = Q/V = (I*t)/V ---> I = C * V/t = 3000F * (1.1V - 1.045V)/3.5s = 3000F * 0.055V/3.5s = 47.14A
 

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