Yep, I have flown with two switches for years. Simply switch on the
new battery just before switching off the old battery. Please, don't
tell me some horror story about "exploding" batteries! I have taken
readings with a 10v 'dead' battery connevted in parallel to a 12.8v
'fresh' battery and all I read was 300 m/a as the fresh battery tried
to charge the dead battery. And don't tell me about voltage spikes
either, *because all those red-necks jumping their car batteries seem
to be surviving quite well, don't they?
JJ

My panel is wired according to JJ's plan. Two batteries. Two
switches. One buss. The avionics shop owner/technician and I
discussed the "make before break" type of switch, but he said his two
switches would work just as well. And as JJ said, switch the second
battery "on" before switching the first battery "off". So far, I
haven't had any probems.

And, I resemble JJ's remark about red-necks jumping car batteries!

Ray Lovinggood
Born and raised in SC, currently employed and living in NC.
And if you want to see some red-necks, just come to my family
reunion...