Won't your indicator read a low green reading with a (actually)dead battery? I thought that was why we buy loaded voltmeters because a dead battery can read normal voltage at low or no load?? I know in rc cars you can be fooled by a dead pack that can pull a small load for a second or two, (like wiggling the sticks??), but move the car about 6 inches. I have put in a battery and "tested it" by seeing it steered...
If you put in a load and switched it just before each flight (to give an equivilent reading to a loaded ESV, wouldn't that be better?
Caveat reader: I am far from an expert! Very, very far... This can be considered much less than my 2 cents worth!
Tom