Charging TT from tow vehicle
I've learned a good bit by reading some of the past posts about charging TT batteries while towing but now I have a couple of questions that I have not seen definite answers to.
Equipment: 2007 Ford F150 XLT, 5.4L, 2WD, Coachmen Clipper 16B TT.
I've added (1) 180W solar panel (not permanently mounted, portable) with a Morningstar controller and a 600W Inverter to use with a television and DVD player when needed. We do a good bit of dry camping and are VERY conservative with our power usage. The solar system is NOT normally hooked up while we are traveling to campgrounds if they are less than 200 miles away. (I hook up the portable solar panel once we arrive.)
I found today that the relay (R05) for charging the battery in a towed trailer was not installed in my truck at the factory even though it came with the Ford frame-mounted trailer hitch and 7-pin and 4-pin connectors in place.
(1) What might be any disadvantages of installing the relay in the truck to enable charging the TT batteries by the truck alternator if the solar panel is NOT hooked up?
(2) If I purchase the relay (probably a Ford-only item) and install it to enable the truck to send charging current to the TT for LONG excursions will it hurt to charge with both the solar panel and charge controller as well as the truck alternator at the same time? (I suspect my solar panel and Morningstar controller actually put out more current than the truck alternator does.)
(Again, NORMALLY the solar panel will NOT be hooked up but there are occasional exceptions when we do longer times on the road. For those trips I mount the panel on the tonneau cover on the truck bed and have cables that run to the solar controller in the TT. It worked well recently on a 6-week tour around the US visiting National Parks. I had NOT purchased and installed that relay, R05 at that time.)
Thanks for your input.
2007 F150 w/5.4 V8
2015 Coachmen Clipper 16B