Is it possible to measure the capacity of a battery if the discharge curve of the battery utilizes a resistor as the load? For example, if a 100 ohm resistor is connected to a battery and then the battery is discharged, would it be possible to calculate the capacity of the battery, based on this curve with this particular resistor (as the load)?
In terms of energy I'd say kind of yes. Let's say you have the 100 ohm resistor, you can take the voltage reading every minute or so. Then, you can record this over time for the duration of discharge. Now, since resistance is constant, by using Power = V^2/R, you can get power at that moment and graph the power over time or just get the voltage graph and divide the whole ting by resistance. Since energy is power integrated over time, you can take the area of the curve you drew and you can say that's the energy that came out of the battery. Though, to get the actual energy, there's things like ESR and other factors but it should be a decent estimate.