Brief Description: Mounting The Secondary 20A B&C Alternator
I will have two alternators in the RV-8. The primary alternator is a 60A unit and have not mounted it yet. It will be mounted on the front of the engine and is driven by a belt around the start ring. The secondary alternator is a 20A unit and is mounted on the accessory case on the back of the engine on the vacuum pump boss mount. Since I won't have a vacuum system on the RV-8, the mount is free for mounting the secondary alternator.
The purpose of the secondary alternator is to provide an alternate source of power if the main alternator goes out on a cross-country flight. The VP-200 electrical system will only allow one of the two alternators to be on at any given time. If the primary fails, the VP-200 will prompt the pilot to switch over to the secondary. All of the avionics pull about 15amps with no other lights on like the strobes or landing lights. This will give about 5 amps to keep the battery charged during the outage. The plan would be that if the primary alternator were to fail, I could fly home on the secondary alternator and then during the landing I could flip on the various lights and strobes which would be pulling hard on the battery, but would last long enough to get the plane safely landed. Seems like a pretty good idea all the way around considering that I have a fully electronic instrument panel.
The B&C 20amp alternator mounted up nicely to the vacuum pump boss with no issues.
