I think you may have missed the point.
The problem everyone is talking about has nothing to do with a "dead battery". Things that are running on the batteries continue to run (and I use the Registered FSUIPC). What is happening is ONLY the Avionics/Radios are dying. It has nothing to do with available battery power.
Many users of the registered FSUIPC, with the "unlimited battery" option set, are still experiencing this loss of Avionics. I, for some reason, have not had the problem once...yet.