Curious.....under charge the digital meter reads 100%.... 13.6V. At rest, fully charged....84%.....12.13V And the trailer "gauge" shows 100% What do you think?
Plug it in for a week, then unplug for 24 hours and check meter
At 12.14 volts your charger should be at 14.8 v charging. More than likely you have a WFCO charger that won't go into boost so you need at least a week to charge the battery