Dave, I spend quite long periods living in carvans with no mains, 6 weeks is failry common the longest straight stretch about 3 years!
I have never had muh success with solar panels, as the size needed to maintain a decent wattage to the battery is very exspensive, yo woul have to spend hundreds to keep up with the consumption of blown heating, tv etc etc, and have more than one storage battery. They are OK for maintaineing charge in a stored caravan, but i dont have much success even with that. I do have a few solar panels I use for keeping electric fence batteries topped up and the difference in time between charges is minimal.
As 'TTT' (with that do as a short version?) has sugested our best option is to cut down on your consumption, i e no use of blow air just gas, no tv etc. I have generators the bestone i have found is a little 650 watt wolf, when using it a couple of hours each evening to charge the battery via he zig and run a small dvd player it runs for about 14 hours on a tank of fuel so is very economical.
as for split chargng, i do it with a smartcom relay (see towsure) and use this to charge a second battery with quick release teminals. But to be honest if you can get away wih using a small generator a couple of hours a day, you wont need one. I use 2 or 3 hook up leads and put the generator as far away for the caravans as possible and it works well for me.
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