Umbilical Cables are the electrical power cables used to link Evangelions in the field to external power supplies in Tokyo-3. The connectors attaching to the rear of an Evangelion are visually similar to a three-point plug. Two large holes in the connector allow a retro-rocket to slow its descent and prevent damage when it is discarded. Tokyo-3 has a multitude of power buildings that house connectors and cable for an Evangelion to switch to a new cable, in case the old cable has reached its maximum length or been severed.
Umbilical cables can be used outside Tokyo-3. A portable version of the umbilical cable is seen in use in Episode 08, being airlifted via helicopter and set on the deck of an aircraft carrier, drawing power from the ship's reactor. Umbilical cables can be connected to other power sources and used far away from Tokyo-3's power supply, as seen in Episode 09, Episode 10 and Episode 18.
Every Evangelion (except for the Mass Production Evangelions and Unit-04) has an internal battery, which functions as an emergency power pack in cases where the Umbilical Cable would be impractical to use, or if it has been disconnected/severed. The batteries have been used several times throughout the series, notably during the two times (once in Episode 03 and again in Episode 25') that an Evangelion's power cable has been severed.
The batteries are mentioned in-show to provide power for five minutes, or one minute at full power. However, it must be noted that the show itself is not consistent in enforcing this rule - for instance, there is no proper reason why the batteries should last five minutes during the battles against Shamshel and the Mass Production Evangelions but little over one minute in the Israfel battle.
With the umbilical cable connected, the Evangelions must connect a new length of cable whenever the cable reaches its maximum length. The battery allows Evangelions a short period during which their mobility is not hampered by the need to stop and change cables.
Battery supplies can be extended without the umbilical cable, using large disposable batteries located on the Eva's shoulder pylons. These provide an unspecified extra operating time and are used in the battles against Israfel and Matarael.
- Main article: S² Engine
Only used by the Evangelion Unit-01 after it ate Zeruel, and the Mass Production Evangelions. It guarantees the unit an unlimited amount of operating time. It is seen in Evangelion -ANIMA- that it has some disadvantages for the components of Unit-01's armor like heat excess. The Mass Production Evangelions, on the other hand, were meant to be powered by a S² Engine. Therefore, their components manage perfectly the energy provided.
Only seen in Rebuild of Evangelion. They are used by Eva-02' and Eva-08 to allow them to operate more freely. They are connected to their back.
- Main article: N² Reactor