Has anyone bought and used one the LPG refill kits for the Red gas gas bottles I've seen on ebay ? Are they any good and most of are they safe and not likely to blow myself and van up ?

Hello all I'm pretty new to this vanlife thing having brought a Chausson flash 9 on a mk7 Transit Chassis last September . I'd appreciate some advice on why my batteries keep draining if its not started for a week or so , I have noticed the batteries are not wired in line or isit sync . I would assume that it has a split charge system on it of some sort and once started it charges well ?