912is volts/amps

Voltage regulators?  They have a history of failing.  I believe the backup ecu switch on my rv12is goes straight to the battery, which might explain the voltage difference. (???)

I had same issue with my 912ULS (no ecu backup) but changed out the voltage regulator and all is again normal.

The alternator B stator or regulator B has likely failed. Or possibly the 3-wire connector between alternator B and regulator B has failed.  Alternator B is not monitored by the Rotax ECU and is normally connected to the airframe after 2500 rpm has been reached for a few seconds. Your indications of low voltage and amps indicate a problem with this system.  

Alternator A is working fine.  This is proven by two things.  

1. The ECUs are not showing a low buss voltage fault so the voltage is OK. Both ECU lane busses are powered from alternator A in normal operation.

2. When you turned on the emergency power switch you tied the airframe power system to Alternator A and the voltage and charging current to the airframe increased. This indicates alternator A is functional, but be careful doing that in this situation, your airframe power needs can easily overwhelm alternator A, which is sized to carry the engine loads, not the airframe loads.  

Alternator B is much more prone to failure because it is sized for average airframe loads. And having the loads too low or too high can be problematic.  There have been a couple of important updates to the system including a new connector between regulator B and the alternator B stator, and a new stator housing with an improved oil spray nozzle to help cool the stator.  Neither were mandatory, but I would do them both if you have to replace the stator.  

Thank you for the detailed reply.

 I am assuming this is a critical repair and needs to be done asap.  The aircraft flies fine but i am putting too much pressure on Alternator A by flying and run the risk of it failing leaving me no backup if i understand correctly? 

I have flown 3-4 hours with this condition so far...

It should be repaired before your next flight. A short ferry flight may be possible starting with a fully charged battery and using minimal electrical loads in the aircraft. You run the risk of alternator A failing with little or no emergency power. 

The emergency power switch is intended to supply the engine systems with emergency power from the battery in the event both alternators fail.  The anticipated use would be:

1. Alternator A fails, and the EMS assumes control of Alternator B, the airframe is no longer charging but the engine is fine.  In this situation you get lane warning lights because the engine is using the alternate power supply. Your airframe electrical system is no longer being charged and running on the battery only.

2. Next, if alternator B fails the engine stops. You then switch on the emergency battery switch and restart the engine and land as soon as possible (before battery power runs out). You would also immediately shed as much electrical load as possible to preserve battery power for the engine and fuel pumps.

Using this switch in the reserve, charging the battery from alternator A, is not discussed in the operating manual and is an option available as a consequence of its intended use. Once you understand it, this can be done, but is ill advised unless you have reduced the airframe loads to a minimum.