We keep ours on charge during the week at home, comes off charge on a Thursday for the weekend in a field somewhere!
We have done this with all our vans we have had, don't know if it's correct, but it is right for us
I use a couple of small solar panel trickle chargers when mines parked up for long periods, one for the vehicle battery and one for the hab batt, works fine for me and I haven't had a flat battery yet :thumb:
smart chargers have only been standard fit on new vans for a couple of years, and even now not all have them. what a smart charger does is measures the charge in the battery and cuts the charge current until the charge drops again. standard chargers tend to just pump out a constant current. this can damage batteries long term if just left plugged in for weeks or months at a time. this damage results in batteries that appear charged but dont provide the rated ah so go flat quickly
if you do plug in at home, switch the charger on for a few days every other week. battery charge needs to be used to exercise the battery's ability to work. if youre constantly hooked up, you wont use the battery, just the charger to power lights etc
as for leaving heating on, its not truly neccessary in the summer, but i put a small oil filled radiator in in the winter to keep it aired. using the vans inbuilt heater for weeks or months on end will result in premature failure of the elements. more expensive to replace than an oil filled radiator and more expensive to run too