"The P100 panel sits on the left side of the aft electrical equipment (EE) bay, and is part of a highly-integrated electrical system that receives 235v ac power from the left engine's twin 250 kVA engine generators for distribution throughout the aircraft."
I have a diagram of the layout of the Aft EE Bay but despite having an 'insert image' icon above, there seems to be no way to upload an image to a post.
The bay is made up of three sections. The battery is situated to the right of the centre section at 'floor' level.
Hope this helps.