Charging RV batteries with tow vechicle

Are you attempting to just get a better charge to the batteries while driving or do you intend on using it otherwise also?

It already does that, albeit it would do it better with heavier wire.

If you do a lot of driving then stopping for a evening without shore power and then driving and stopping again without shore power then it would be worth it. If you stop where the is shore power its not worth the hassle. If stopping for more then a day with no shore power then a small genny would be the ticket. I thought about doing the same but I decided to rely on my genny. My converter charge does a great job and I do not have to keep my truck running.

I thought most systems will do that. I checked mine when we first bought it and found the charging wire, the white one IIRC, was a very light gauge, so I beefed it up.
I thought it worthwhile to do.

I have researched this and there is no charge going to the RV thru the 7 pin connector. I also checked with a multi meter. I just wanted to be able to charge the batteries while traveling, not setting at a camp site. I am leaning towards buying a Honda generator. The stove,frig,heater,and hot water are all propane and I changed all the interior lighting to LED. I don't need to watch TV or listen to a stereo, so the only draw on the batteries should be the water pump. But if I stay at a state or provincial park a few days and the next stop will be another of the same, I not sure how many days the 2 RV batteries will last.

It should charge through that 7 pin. My guess is that there is a fuse missing which provides the power. Take a look and check the manual as well.

Solar also works while driving on a sunny day.

I have a 2011 Chev truck and was surprised to find that the truck, factory wired with a trailering package, didn't have the wire hooked up to the 7 pin. The wire was there and I found on the Internet where to find the wire, and the stud to hook it to in the fuse panel under the hood as well as the location where the fuse needed to be installed. It took a special fuse, 40 amp, I think. I'm not sure of the reason for running the wire, but not hooking it up, but it wasn't hard to find the information on the web.

Most trucks are wired to charge as you drive . Some will require that you install a fuse under the hood . What kind and year truck is it ?
No heavy wire is needed for most of us . I drive 3 or 4 hours a day and then dry camp and have plenty of power in my pair of 6 volt batts .

Well,well well. Isn't this interesting. After hearing all you folks saying it should be working, I found this tid-bit on a forum.

F-150 Charging TT battery while towing
This came up when a friend of mine realized that his F-150 was not charging the camper battery while he was traveling. Here's what we found out. Ford does not ship their trucks with the ability to charge a camper battery while towing. Why?? It's our guess that they are concerned with having a 12-V hot wire going the length of the vehicle and it's only being used by those pulling a camper. Here's what they do. All F-150's are shipped with a plastic bag shoved somewhere inside the truck, door or glove box storage. Inside the bag is a fuse, wiring harness with a plug and a relay. The relay goes into slot #9 in the main under hood fuse box just behind the radiator. The fuse, 30-amp goes into slot 21. The wiring harness is used if you don't have the factory installed brake controller.

Sure enough they were in the glove box, and I installed them in the fuse box. Leaving for Alaska April 28th. Thanks for the help!