The Tesla cannon is a pre-War, portable, directable energy weapon. It was designed to be used as a lightweight, compact anti-tank weapon. The design was named after Nikola Tesla, whose designs for the technology were seized by the U.S. government after his death. When used, the cannon projects a blast that will damage the enemy on impact. It will continue to gradually reduce the enemy's health due to its ability to electrify the target and its surroundings.
The Tesla cannon is a shoulder-mounted energy weapon that is powered by electron charge packs. This weapon has a high Strength requirement for its weight and the fact that it's a recoilless energy weapon. The sound of the Tesla cannon firing has also been changed from the one in Broken Steel.
The Tesla cannon is rare, especially so if players kill off the Van Graffs, thereby eliminating one of the only specialty energy weapon vendors in the game.
After completing the Honest HeartsAdd-On, the cannon will respawn in the Brotherhood Safehouse footlocker.
Because the Tesla cannon uses 5 electron charge packs per blast (which only accounts the fact that you fire once), it's only possible to get 1 empty electron charge pack from firing the Cannon, the same with all energy weapons that uses more than 1 cell per shot.
Due to it previously firing only 1 shot per reload, it ejects electron charge packs every shot which is strange considering only one is loaded. Also, the electron charge pack will not appear after one shot is fired, and the end of the cannon is retracted, but it still ejects another per shot.
The Tesla cannon can not be Jury Rigged with any other weapon, but can only be repaired with another exact copy or its unique variants, this is because there are no other shoulder fired energy weapons in the game.
The Tesla cannon was originally to be featured in the canceled Fallout: Brotherhood of Steel 2, bearing no resemblance to the weapon in Broken Steel. Described as a "high-powered mass-cannon throwing tessellated plasma forward in an orgy of death and destruction" in the Fallout: Brotherhood of Steel 2 design document, it was to be the so-called "uber-weapon" of player character Maxus. "Uber-weapons" were to be unique weapons for each non-player character which had to be assembled from 5 parts over the course of the game. One of the five parts for this weapon was a Tesla coil.
Nikola Tesla really did try to create a directed energy weapon but it would have been a particle beam weapon called a "Teleforce", something that would be immensely complicated to create - laser weapons would be simple by comparison.
Picking up the bulk energy cells above the cannon in the Brotherhood of Steel Safehouse before picking up the cannon below it will result in the cannon being picked up but will not show up in the inventory. The 8 WG will still apply however. Considering there is no known way to drop it, it will cause a permanent increase of 8 WG.
Because the Tesla cannon fires more than once per reload, in third person an electron charge pack will continually be ejected from the rear port, despite none appearing after the first shot.