You may (or may not) be getting a 10-amp charge through that six way plug and socket. I tried using them with a 8-gauge wire and turned both the positive and negative contacts inside the plug and socket into annealed overheated junk. Several tries pure failure.
A Bi-DIRECTIONAL charge solenoid is a good choice. Connects and disconnects truck and camper automatically. Charges from either direction. No switches nothing to fool with. I would recommend the 200-ampere model because you may end up with a pair of AGM batteries. Wired with 6-gauge wire a separate dual contact plug and socket made special for this job will allow that AGM to fully recharge in a couple of hours of running the engine.
With a pair of AGM batteries even a HUNDRED AMP converter would not be overkill if you have enough generator capacity to run it.
My bus has a 400-amp 28 volt Niehoff alternator. Very high amperage Sure Power 24 to 12 volt converters.
I want to charge my AGM Group 31's with my toad alternator. So off comes the 40/90 original alternator 90 amps max, and I am going to rehab a 50/120 MoPar alternator with a stator design of my own labor. Probably a triple wound Wye stator with around 140 amperes potential but a 35 ampere increase at dead idle. I write this to give you a perspective of what can be done with a rig with a pair of group 31 AGM batteries. Your truck probably has a monster alternator right from the factory - all you need to do is get it's potential to the camper batteries. I do not have any experience with the eu200i. BFL13 could probably tell you if it will successfully run a 100-amp smart converter.
BEWARE of partially charging AGM batteries, day after day, week after week with solar. It will damage them. My personal break point is 7-days of partial recharges then a full and complete recharge. If you do not wish to lug your generator around then I would de-emphasize a monster output converter and instead concentrate mightily on a top-notch alternator charging circuit.
Sure Power: 12V 200A Battery Separator - Bi-Directional w/ Aux Start
Here is a link to one of the critters. As as example. Shop around.
http://www.ase-supply.com/Sure_Power_1314_200_Battery_Separator_p/sp-1314-200.htm
Easy as pie to install
