Source: Starfinder Core Rulebook p.121
As a move action, you can expend an unused spell slot to refill charges in a weapon's power cell. This requires you to touch the weapon or its power cell. The power cell regains 10 charges per spell level, up to its capacity. You can also use this ability to jump-start or short out an electronic device, allowing you to attempt an Engineering check to disable a device with a bonus equal to double the level of the spell you expended.