Wiring dual batteries in a dual motor starter box, a little help?
 

I have 2x brand new nimh batteries sitting here and was wondering how I would wire it up to work with dual batteries. It's set up for gel cell but I just have these things sitting here. I searched but couldn't find a really good diagram, anyone using one could throw up a clear pic would be greatly appreciated or explain it to me lol..Here is my starter box..
+/- +/- ?
http://www.amainhobbies.com/product_...-Panel-Battery

+ --------------- + Motor
Battery 1
-
l
l
+
Battery 2
- -------------- - Motor

This will double the voltage of a single battery and is called "series wiring"