I also concur with Brent, but I arrived at perhaps a diametrically opposite conclusion from Fred's.  I also have dual Chelton screens, but only have one battery and one alternator.  The backup is a vacuum-powered 6-pack in a standard configuration on the right side.  True, it isn't in the "normal scan" as Brent would suggest, but it is close enough to fly by it.  There are no "manual work-arounds" as Fred has.  The idea is that the weak link in the chain (the pilot) will probably turn to mush in an emergency, so let's reduce his workload, not ask him to do more.  If there is an electrical failure, the idea is to get on the ground, if necessary with the handheld radio, and fix it there.  Just my thoughts.

Gary

Previously from Fred:

Brent has written much on this topic including "In my "Glazed and Confused" presentation on "Glass Cockpits" I say that flying an aircraft with a non-certified, non TSO'ed glass standby (Dynon et al) is like jumping out of an airplane with only your main parachute and your standby plan is the fact you are wearing real soft socks."

 

I concur. 

 

When I was young and stupid (not long ago) I had thoughts of long overwater (think trans-Pacific) flights.  I also have experience with failure modes assessment analysis (FMEA) which frequently shows up failure modes easily over looked.  After reviewing various electrical and instrument configurations I arrived at a system design which is shown in simplified form in the attached sketch.  It consists of two alternators, two batteries, four busses, and a lot of opportunities for cross tie.  I use dual Chelton screens, with PFD off the essential buss (many sources of power), the MFD off of the avionics bus (which has many sources of power), and back up electric attitude  indicator (on essential buss), turn and bank (essential buss) and air speed and altitude indicators.

 

You show me the failure and I can show you the automated or manual work around.