So far no one has mentioned what really made my decision to go with 12V in my L4P, and that is the engine cranking requirements. If you have a normally aspirated engine and higher compression, 8.5 or more, and your battery is mounted with long cables, vs firewall, then you may want the 24V system? But with my Turboed engine and lower compression it was much better to go 12V. Many more things that run on 12V also. So the only concern was Amp load. You can see my panel under bench test and it required only 14 amps, without the remote boxes. So I used the normal 65 amp alternator and a 20 amp back up B&C.

In the last 350 flight hours I only had the Low voltage light come on once while taxing with everything powered up and Full AC with full fan on and spending a lot of time on the ground. Then at full power take off when I put the gear up and the hyd. pump demands a lot of amps. That was once and is not the usual case even with the AC on.