A123 lawn mower...

[lincpimp]

You can wire the packs in parallel, I would do it off the main leads with bullet connectors, that way to can separate them easily if necessary. That way you could separate the packs to do a maintenance charge every now and then. Plus if you ever plan to sell the packs they can be sold individually. How do you plan to charge a 12000mah lipo? You can make a harness to parallel all of the balance connectors together for balance charging. That is what i would do. If you only plan to use 40-80 amps 12 gauge wire is plenty.