prismatic cell discharging test

can i perform a discharge test on a prismatic cell and know its capacity.

by connecting the cell to a low voltage heating element to discharge . and measure the Wh in a wattmeter (150A Digital LCD Volt Ampere Wattmeter Power Analyzer Solar )

in the end, by measuring Wh .i might get total discharged Watts.

also i have a doubt about making a auxiliary supply for the watt meter (cuz i think wattmeter operating voltage is 5v )(and the cell voltage is 3.2v). help me. sorry if i got this all wrong.

Yes, can be done.

Most accurately with an electronic dummy load, or a charger designed to do this

using a precisely regulated CC amps rate

usually the 10-hour rate 0.1C or lower if you are trying to verify vendor claimed capacity.

Cheap cells like that you might get 90%, top notch makers often deliver 5-10% higher than nameplate.

Coulomb counters like that are usually only good for ballparking, observing declining Ah as batteries wear.

Usually DIYers use banks of light bulbs or calibrated braking resistors, for high currents use water cooling

https://www.rcgroups.com/forums/showthread.php?1107072-How-to-build-a-constant-current-discharger

https://endless-sphere.com/forums/viewtopic.php?p=1625753#p1625753