Actually the larger the engine, the harder and more spark energy it takes to run it. I am running my 60 on the single Lipo. It is a 20c lipo so the EI will never draw enough current to even effect it. Who says it takes 4.8v to run an EI system? They are only set up to run on that because that is the batteries we run. I can not give all of the technical reasons why a 3.7v battery works. I just know it does. I fly, it runs, top RPM are the same on the 3.7 as a 4.8 pack. Idle is the same. Transition is the same. It works and that is all I care about. Also a 1.4oz battery for over 2 hours of flight is kind of nice. Who care what it SHOULD do on paper. What it DOES do in reality is what matters. In reality, with that EI and hall, it works, and works well.