sounds to me fella like youve got a severe drain on ya van.best thing to do is use a multimeter on amps and see what drain you have.anything under .5 amp is good but any higher and then your problems could begin as you will need to find out what circuit is draining the battery.easiest way to do this is to have the multimeter on then pull each fuse out 1 at a time,this will give you a clue as to the circuit that is draining then can go from there