Jsn had has it right. As long as the batteries aren't Lithium batteries there will only be two wires going to the actual battery terminals. They will use standard plugs that have 3 prongs on them and the standard 3 conductor wire, but only the red and black (positive and negative) wires will be hooked up.

If the batteries are Lithium the other wires are used to monitor the health of the battery. That's about all I know about the Lithium batteries and I'd hate to give out bad information about them.

Two great places to find information on batteries are:
[link=http://www.rcuniverse.com/forum/forumid_84/tt.htm]Battery and Charger Forum on RC Universe[/link]
[link=http://www.rcbatteryclinic.com]The RC Battery Clinic[/link]

Hope this helps

Ken