EMS Backup Battery (12iS)

[KEG]

Two questions: (RV-12iS)
1. Does turning on the EMS Backup Battery Switch supply power for the system from the main battery or the IBBS-12V-3AH backup battery?
2. Is there a way to test if the backup system is working properly?

 

[Fisherpd]

For the RV 12iS with the iS engine - The EMS backup battery switches the main battery to power the engine ignitions systems.
The name is a bit ambiguous - it enables the backup connection to the battery, it is not enabling a backup battery (There isn't one)

The procedure I used to verify the backup power to satisfy the Rotax generator cooling oil nozzle SB requirement is as follows:

1 - start engine normally
2 - wait for Start power to be removed.
3 - stop engine using A&B ignition switches - do NOT turn off Master.
4 - Attempt to start Engine - Engine should not crank - verifying that the start power has been removed.
5 - Switch EMS Backup Battery switch on.
6 - Start engine.
If the engine starts you have verified that the backup connection to the battery is functional, as the normal (start) power was disabled. Thus if both generators fail (because of cooling oil issues or any other reason) you have reasonable confidence that you can use the main battery to keep the engine going. But because it is not being charged - you should "land at the nearest practical airport" while keeping an eye on the battery voltage.

 

[Fisherpd]

Since running that procedure I saw a couple of posts that indicated that the start power is removed when the A generator starts to charge the battery. So you do not need to wait for start power to be removed - just run the engine above 2500 to switch the generator and proceed to shut down the engine.
Also don't forget to turn the EMS switch off after running this.