Noob Question, Object reference

I have the following very basic code, and I just can't seem to figure out what's going wrong. No matter what I change I get the error "An object reference is required to access a non-static member".

 public Battalion battalion;
 
 void Update()
 {
 Battalion newBattalion = Instantiate(battalion) as Battalion;
 UnitCare.addBattalion(newBattalion);
 }

Where addBattalion is a very simple:

     public void addBattalion(Battalion battalion)
     {
         battalionList.Add(battalion);
     }