Anything that uses AP will drain the fusion core more quickly. Sprinting, jumping, using VATS.How fast does it deplete? If I don't run , jump, etc? Can it last me for a while? How many hours of continuous usage?
I know there are perks to improve it later on, but Im asking for the stock experience
Once you get Power User level 3 fusion core drain stops being an issue. I've got over 300 hours in the game, the vast majority of it in Power Armor, and I never drop below having 70 cores.
A good way to get cores is to claim the power plant workshops.
Fusion core processor
The fusion core processor is a world object and type of mineral extractor in Fallout 76. Fusion core processors produce one fully-charged fusion core every seven minutes and can store a maximum of three cores (as of patch 1.0.2.0). These serve as a way to stockpile fusion cores to provide power...
fallout.fandom.com
But you really need Batteries Included and Power User before you seriously start using power armor. Fusion Cores weigh a lot without Batteries Included.