The charger was tested correctly - by the amp output.
And it is working overtime.
The max output should only be about 2.5A, and it should only put this out if the battery is very low.
If the battery is fully charged, it should only put out about 0.2 amps.
The first thing I have to mention is that if this set is only 2 years old, it should still be under warranty.
If so, you really need to let a Generac representative take care of it.
Working on the set yourself could very well void your warranty.
The problem is that the charger is built into the control board, so it can not really be isolated from the system - at least not easily.
If I were working on this set, what I would do would be to go to the set and take the cover off the control panel.
I would disconnect the wire number 56 from the starter relay (to keep the engine from trying to start while I do all of this).
Then I would CAREFULLY disconnect the small wires marked N1 and N2 from the terminal block. CAREFULLY, as these wires carry 240 volts. I would cap them off tightly to keep them from shorting out.
Disconnecting the N1 and N2 from their power source will disable the charger on the board.
Then I would remove the positive battery cable from the battery.
I would take my multimeter and set it to DC Amps, and connect the red lead to the positive post of the battery, and the black lead to the battery cable.
this would tell me if there was a draw on the battery while the set is sitting idle, with the switch in AUTO.
There should be no noticeable draw.
If there was, then it gets really hard, trying to find it.