RE: KMP Edge 540
I have two RX batteries and two switches in my Edge but when I do my 30% Yak I will just put one battery and switch in it. I am like you, I have been doing this for many years and have not had a battery go bad yet. If you take care of your batteries you should not have a problem. The second battery is not much help anyway unless you put a diod on each circut to protect one battery in case the other has a short.
Tom