darth vader can choke anbody at anytime and everyone at anytime, vaders power is highly overlooked, so in mere seconds the entire fleet could come crashing down. but if were not talking force powers you ca go watch game theory on the energy sword lightsaber battery dolima. in weaponary, star wars takes a hard w because once the uncs sees the death star destory a huge ship or planet, they will retreat immiediently
Vader's power? In comparison to Sidious (and a WHOLE lot more), he's a baby. Sidious can destroy planets and summon Force Storms in Legends, and I think I remember him creating a black hole too (again, Legends).
Besides, since the Halo Universe comes from another Galaxy, the Force has less effect on them (not immune, just more resistant, like the Yuuzhan Vong).
As soon as the UNSC would see the Death Star, they'd rain it down with kinetic bolts from their MACs. It's simple.As soon as the shields are down, the Death Star is as good as space scrap.
The same goes for the Covenant. They'd likely use their glassing beam, applying ungodly pressure on the shields, which eventually collapse and the beam melts the station. A single CAS would be more than enough to deal with a Death Star. Which is why I always say: the Death Star may be powerful, but against the UNSC and Covenant, it's nearly useless.
As for the Energy Sword vs Lightsaber argument... don't bring Game Theory to this. Last time I watched him, it was years, because he wasn't doing his job correctly. In fact, every Halo video of his always had a mountain of wrong information and assumptions.
Anyway: The Lightsaber not only has more forms of combat (7, specifically), but is, overall, more maneuverable. So the battery issue (if it's even an issue) matters little, if at all.