Therefore, an additional branch containing all three additional batteries should be added in parallel to the existing voltage combination. The 30V battery should be
connected with its negative terminal at the same potential as the original voltage combination. The negative terminal of one of the 20V batteries should be connected to the positive terminal of the 30V battery. The positive terminal of the final 20V battery should be connected to the positive terminal of the other 20V battery. (The actual order of the batteries within the branch is unimportant; this particular order is used to clarify the discussion.) The new voltages are indicated in the diagram:
