I can only see the positive connector. The rest of the battery is covered by a large plastic piece.
What is the easiest way to access the negative connector?

 

Not designed for you to access the negative connector if you are going to give/receive a jump or trickle charge the battery. Designed for access to the negative post if your are going to replace the battery after removing the air resonator intake. There is a metal hanger post with an eyelet on the left side of engine block near the engine cover for connecting to the negative side of the battery..

 

Pull of the black cover that is along the edge of the front of the car that is covering the hood latch. Remove the 2 black plastic pop up connection from the Air inlet element which is located right over the top of the battery. Now you will be able to access the Negative Battery Cable.

 

leave the battery alone except to replace it. Go with this solution above ^^^^^

 

Are you referring to the inlet shown in the picture ?

 

Yes, that is for the jumper negative jumper cable.

 

Cool. Thank you.
Much easier than disassembling the plastic components!