Building lipo packs... hmm, dunno if that sounds like fun or a recipe for disaster. Hope you have a good iron and the tabs arent made out of something funky that requires special flux.
More to the point, those are 2s packs, you cant turn a 2s pack into a 3s pack without ripping it apart to harvest individual cells, and .. see above comments.
What you need is a pair of these, wired in parallel:
http://www.hobbycity.com/hobbycity/s...0C_Lipoly_Pack
Same length, and they are already in 3s configuration.
