Hi, my name is William. I am developing a large unmanned VTOL aircraft similar in function to the Convergence RC model. The 2 tilting motors in front motors run on 14S batteries. The one in back needs a 28S battery. 

I would like to operate the motors using only two 14S batteries. My idea is to connect the 2 batteries in series for the back motor and tap off each battery for the front motors. I will be using Opto ESCs, so that the input signal ground is issolated from the power ground.

Has anyone tried this before? Does anyone think it will not work?

Thanks, William