On shore power for 4 days the battery should have been fully charged. It's not clear when you put on the 'trickle charger'. You had to do that in the campground or ?? Also, you brought in the slides under battery power alone (disconnected from shore power and tow vehicle not connected or not running) before retracting the levelers?
Keeping the shore power connected and the battery charging while you bring in the slides and retract the levelers will keep the maximum voltage and make life easier for the 12v motors.
Hearing the fan in the converter is normal. We usually notice ours when we turn on the awning lights and the battery is charging. Yours was probably due to the battery charging (battery felt warm and you heard bubbles). The converters have a temp sensor that turns the fan on and off.
You should probably have the battery tested to rule that out as a problem and have the dealer check the battery charging voltage when on shore power.
Hope that helps.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
2015 Jay Flight 27RLS (Nights Camped: 102 '15, 90 '16, 80 '17, 161 '18)
2006 Ford F350 6.0 PSD, 4WD, CC, LB, SRW, Camper pkg, Equal-i-zer, GY Endurance (E)