we camp 70 % without hookups , often with other camper friends.
we do not have a generator or solar .
our extended group does not allow generators .
we have been doing this for 15 years .
we use a set of 12 foot Heavy Duty jumper cables .
after setting up our trailer we turn our diesel pickup around and run off of 4 batteries total .
the pickup gets driven every second or 3rd day .
those 2 batteries get fully charged .
immediately upon returning i use the jumpers to connect the 4 batteries again.
the 4 batteries tend to equalize .
i do not run the pickup in an attempt to recharge the RV batteries anymore .
the electronic controller of the refer is the item most critical for voltage .
if the refer warning light goes off then you need a charge .
that does not happen using the 4 battery method .
we conserve our furnace usage and take advantage of the factory supplied 12V flourexcent lights in our Komfort trailer .
we charge the RV batteries fully at home for the day prior to camping .
i always disconnect the RV batteries for storage after our camping trip .
my RV batteries are old but have held up very well because i have neither overcharged them nor have i let them stay " flat " for very much time .
i upgraded my duramax to AGM batteries Exide EDGE .
if i find a deal on some AGM batteries for my RV i will upgrade them also .
save your money . buy 12 foot HD jumpers and maybe some upgraded batteries .
get some LED lights .
to help conserve juice we use the LED headband lights in the campground , a propane lantern in the colder nights to take the chill off the trailer when turning in and on very rare occasion our mr. buddy propane heater .
you can buy a lot of AA batteries , and propane bottles for the price of a solar panel .