I've long been attracted to the Z12 drawing for my RV-9A project and recently heard of the Z101 drawing having several new features of which the aux/clearance-delivery/pre-flight bus and brownout booster are the most interesting.
I don't like the way the brownout booster is connected to the aux relay in the Z101 drawing. In order to get the benefit of the booster the aux switch must be off. If you switch that off before turning on the main battery master, then you shut down the computer you just loaded your flight plan into. It is not a good idea to have to flip switches in a particular sequence.
Perhaps it's enough to simply move the brownout bus connection to other (energized) terminal of the aux relay. Or perhaps connect the brownout booster directly the pre-flight bus terminal. In either case a diode might be in order although the brownout booster implies that it acts like one with input/output terminals.
Those two thoughts beg another question for more electrically savvy people than me to judge: Why would the current for the brownout booster is be drawn from a circuit (starter engage) that is intended to only energize a relay (starter)? If the AUX switch energizes the pre-flight bus via a relay (S704-1), would it not follow that the brownout bus carrying the same loads also ought to be energized via a relay? Perhaps its load is too transient to matter. I dunno.
I don't like the way the brownout booster is connected to the aux relay in the Z101 drawing. In order to get the benefit of the booster the aux switch must be off. If you switch that off before turning on the main battery master, then you shut down the computer you just loaded your flight plan into. It is not a good idea to have to flip switches in a particular sequence.
Perhaps it's enough to simply move the brownout bus connection to other (energized) terminal of the aux relay. Or perhaps connect the brownout booster directly the pre-flight bus terminal. In either case a diode might be in order although the brownout booster implies that it acts like one with input/output terminals.
Those two thoughts beg another question for more electrically savvy people than me to judge: Why would the current for the brownout booster is be drawn from a circuit (starter engage) that is intended to only energize a relay (starter)? If the AUX switch energizes the pre-flight bus via a relay (S704-1), would it not follow that the brownout bus carrying the same loads also ought to be energized via a relay? Perhaps its load is too transient to matter. I dunno.