Did some more troubleshooting today and the conclusion is the Bargman trailer umbilical is my problem. When I use that to connect the charge controller to the battery, the amps top out at about 1.2.
If I connect directly from the charge controller to the battery with about 2' of 10 gauge wire, I see 5.2 amps charging the battery.
Any ideas why the Bargman connector method is so poor - it is a 13' 2012 scamp
so the umbilical can't be that long. Almost seems like maybe the way they have the Bargman tied into the trailer that there is some current limiting going on (maybe so that it doesn't draw too much from the vehicle when connected?).
Wish I would have known that before special ordering the Bargman connector and chopping a big hole in the side of this nice pelican box. Seems like I'm starting over now with a strategy for connectors and housing the controller.
Oh well, I'm thrilled the panel and controller are working fantastic.