I used the Expbus II for my electric control panel. Price now is $299. This unit has toggle switches for Master, radio master and just about any other electrical control for avionics/radios, fuel pumps, lights, back-up battery, charging control, alternator cutout, automatic isolation and switch over for line and back-up batteries, solid state circuit breakers with automatic reset, etc. The 40 amp alternator relay is built in. Read the spec sheet. http://www.aircraftspruce.com/catalog/elpages/expbus.php The Expbus 2V at $418 is the exact same as the Expbus II except the 2V has rocker switches and has a mounting tray. I made my own mount to fit my layout better. The toggle switches have a better reliability than the rockers. (The toggles will probably gouge my face more if I might, someday, try to get to the crash site before they do.) I am using a 17 Ah and a 7 Ah back-up sealed batteries. I have had my panel operating but not flown yet. Yes, wiring this system is as simple as they advertise. Don't forget to put in a central ground bus also.
Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA smw...@md.metrocast.net ------------------------------ >I'm not sure if this would work in a plane as a back-up. But in RVs and >boats in order to use 2 different batteries for instance a car battery and a deep cycle battery, A simple cross-over circuit is used that can be purchased at any RV or marine store. The cross-over is pretty much just a high current rectifier bridge that allows current to travel only in one direction. "In designing my back-up system I took care to completely isolate both systems . . . except for the occasions when I might want to connect them . . . which would be to charge them concurrently, either in the hanger or in flight."
