Electrical Question for Experimental Homebuilt

How many amperes can a Cessna Split master switch carry? I'd like to run
12-16 amps on alternator side and less on the battery side. John Deere
tractor alternator/regulator and small motorcycle battery. Would like to
avoid relays if possible..

Thanks, Dick

Can't give hard figures, but I would expect, from handling
that switch, that 10 amps DC would be plenty to expect of it. Most such
switches suffer when the circuit is opened and arcing occurs at the
points, and DC is much worse than AC for that.
The reasons that certified airplanes use relays
("contactors" or "solenoids") include the ability to switch large
amounts of current without the heavy wiring running through the
cockpit, which adds weight and cost, and the risk of electrical fire
with such an installation if something shorts the line between the
battery and switch. The battery can't be isolated in that case, and
consequences could be serious.

Dan