As builders I think we can help eliminate some of these complicated control systems. Sometimes there are many options for adding switches. In general less is more. I recently went through my "final" configuration and I tried very hard to reduce the number of switches and to not put multiple functions or modes on one switch. Its ok if the functions are relating like landing lights and wig-wag mode but from reading threads here I often hear about folks that share unrelated functions on a single switch.
I have 2 alternators and a single battery. My alternator switchover is automatic. I originally had a cross-feed switch but I realized I really didn't need it. It would have become something that had to be switched at the correct moment in time. I think when you go from my configuration to 2 batteries you then add another level of complication and intern likely more switches to handle all the possible configurations.
As the builder we might have researched all of these options and understand the implications even more the more complicated configurations. However, once we sell the aircraft the buyer has a completely different level of understanding. We need to keep it simple and document the operation.
I do agree with Larry that the owner in this case had several opportunities to realize he had a real problem. Low operating voltage, having to charge the battery and who knows what else. It does make me wonder if buying an experimental as a non-builder shouldn't have some sort of minimal systems operations basics training requirement. I have been flying a standard rental C172 lately and it is quite different than the systems I'm building into my RV-7A. Pilots trained on the typical rental Cessna may likely not have a detailed understanding of systems operation.
2020 Donation Paid
Titan IOX-370, Dual PMAGs, 9.6:1 Pistons, FM-150
RV-7 Fuselage in progress
* Cabin Interior - In progress
RV-7 SB Wings
* Both Wings fully skinned
* Fuel Tanks Complete - No leaks finally
* Ailerons Complete
* Flaps Complete
RV-7 Empennage - Complete (a little fiberglass work left)
Vans Training Kit # 2 - Complete
RV-7 Preview Plans
Vans Training Kit #1 - Complete
EAA Sheet Metal Class - Complete