On 3 helmi, 18:10, JohnDeRosa wrote:

At the panel I use three switches to run the batteries in parallel.
Battery 1 on/off, battery 2 on/off and then the output of both to a
master switch and then to the avionics. *The thinking of separate
battery switches is that you can disconnect a "bad" battery. *I always
have all three switches turned on during flight - the need to be able
to turn off a bad battery hasn't arisen for me and I am unsure how I
would even know (everything dies? *smoke?).

You would know that by total power loss of all your batteries. You
have essentially parallel connection with all your batteries during
flight. When one fails, it drains your good batteries empty. When your
radio or computer starts blinking it's too late. Best option is to use
simple selector switch to choose one battery at time, and keep other
batteries disconnected.

rk