across Downtown Hunrath
The battery is a large device which, early on in the game, C.W. asks the player to connect. It is located right next to C.W.'s workshop. A train bridge passes in front of it and leads to the central big Tree of Hunrath. On the side of the bridge tracks, we see heavy cable connectors of the same kind as the ones coming out of the battery. In Farley's journal, found much later in the game, Caroline Farley expresses her intention to sway C.W. from his "battery" plan.
Description[]
and tubes under the battery
The structure looks like a big blue metal water reservoir on top of an equally big Tesla coil, with massive cables and tubes protruding from underneath, where also a casing houses the main connector of the battery. The whole device is mounted on a metal platform with a walkway around it, all of which is set on metal supports anchored in the rocks below. Around the device are connected three Villein technology parts with tubes connecting underneath the platform.
Operation[]
Inside the connector casing we find the Battery/Capacitor Log, a document which indicates that the battery is a rechargeable one. We learn that it charges via focal panels absorbing 'the power generated by the maturation of the Trees' (see Bleeder). After charging the battery, this power was passed to the Bleeder which controls and dissipates it. It is also evident from the document that C.W. had to replace the connector with a safer one due to some "critter" interference.
Endgame role[]
The battery plays a significant role in the final part of the game. More about this can be found in the Walkthrough pt.21 (spoiler warning).