Q: When my van sits overnight it won't start until I jump it.

Check the battery for any parasitic load applying to it. To do this, make sure that the battery is fully charged and remove the negative battery cable from the battery. Then put a digital meter cables on the negative battery cable terminal and the negative battery post. If the meter has a voltage measurement, then there is a draw on the battery. With the key out of the ignition and the doors shut, operate everything in the car and when the meter read 0 or near 0 volts, then you would have found the source of drainage. If you need further assistance with your battery not holding a charge, then seek out a professional, such as one from Your Mechanic, to help you.