I need to measure the discharge power of a battery in general.
At the end i want the maximum charge/discharge power as a function of the state of charge(SOC). So i need a curve that looks like the figure that is displayed here.
I already calculated the power as a function of the SOC but i am not sure if my method is correct.
Lets assume we are looking at a lithium ion battery. I found two ways to calculate the power.
The first one was simply using the voltage curve as a function of state of charge for different C- Rates. Then multiplying the Current with the voltage and getting my power. P(SOC) = U(SOC) * C-Rate.
The second method was using two graphs of a battery the voltage as a function of the SOC and the internal resistance as a function of a SOC and then P(SOC) = (U(SOC)^2)/R(SOC).