All this data is potentially out of date, and should be taken with a truckload of salt
The capacitor of a ship is a power storage circuit that is used to activate fitted modules. (Note that the capacitor is distinct from a ship's powergrid. Also note that running out of capacitor power does not render your ship immobile.)
A ship's reactor provides power to essential ship systems, but many modules in order to be activated require a burst of power which the reactor is unable to provide. Capacitors therefore are installed to meet this need. The reactor fills the capacitor with power, the capacitor stores this power until modules are activated. As modules are activated, power is drained from the capacitor, which then causes the reactor to add more power.
A capacitor has two attributes: capacity (how much power it can store) and recharge time (how much time is needed for the reactor to fill it).
The amount of power that capacitors can store varies, although usually it varies by size of ship: the larger the ship, the larger the capacitor. The capacity of capacitors can be increased directly by training the Energy Management skill. Also, a huge variety of skills, and in particular those in the Engineering tree, reduce the amount of power needed to activate modules, thus indirectly improving capacitor capacity.
There are modules and a combat booster that further increase the capacitor capacity. A few modules are listed below:
The following rigs also affect capacitor capacity:
- Small Semiconductor Memory Cell I | Medium Semiconductor Memory Cell I | Large Semiconductor Memory Cell I
The amount of time to fully recharge a capacitor also varies, in this case usually by the size of the capacitor: smaller capacitors tend to recharge faster. Capacitor recharge time can be reduced directly by training the Energy Systems Operation skill.
There are modules that reduce the recharge time, a few are listed below:
The following rigs also affect capacitor recharge time:
- Small Capacitor Control Circuit I | Medium Capacitor Control Circuit I | Large Capacitor Control Circuit I
Role in combat
If the capacitor becomes fully drained, a ship may be unable to fire its weapons (if they use capacitor, projectile weapons and missiles are unaffected), warp out from combat, or use any of its modules, and may wind up being left with only the ability to launch drones and move around. Running out of capacitor power in the middle of combat can be fatal.
There are modules that can neutralize an opponent's capacitor power, can steal it and add it to your own, or can allow allies to transfer it among each other, so capacitor management is a notable aspect in warfare. Some of these modules are listed below:
The following rigs affect efectiveness of the above modules:
Capacitor is also used by the ship's warp drive. The longer the distance is, more energy is needed to initiate the warp. Sometimes a ship cannot make a very long warp in a single try. There is a special skill that reduces capacitor need for initiating warp: Warp Drive Operation. Certain rigs can also reduce energy needed by the warp drive, for example Small Warp Core Optimizer I.
All capital ships and Black Ops battleships need a lot of capacitor charge to perform a jump between systems. Basic capacitor need for a jump is 95%. The Jump Drive Operation skill reduces energy needed by 5% per level, so the actual amount of capacitor needed at level 1 is 90% down to 70% at level 5.