Im interested in buying one of those new Sullivan cordless battery boxes,,,,,Im just curious about what type and size battery(NIMH) to put into this unit....Has anyone have one of these yet. Its fairly new on the market. I just want to be sure that I get a battery that will fit properly inside the box.

Thanks in advance TAZZZZ

The type of battery is up to you. Get whatever type you can easily charge. Voltage and size is what matters. 12 volts for the starter then the panel step down to 1.5 volts for the glow plug.
I used to use a rechargeable glow stick and a car jump starter for the starter. The 12 volt sealed batteries I used were only good for about a year

I used to do what Jet is describing but went to the simple button a few years back. I haven't seen the new Sullivan item your asking about but simple is better. I just use a Harbor Freight 18 volt battery attached to my starter, no long wires to worry about, a glow stick for the glow plugs and a hand crank fuel pump. Less is better.