You know we need more information than that. Does this happen while driving? After the van has been sitting for a month? What's the symptom? How old is the battery? Have you had the charging system tested?

i use car, does not happen while im driving, went to turn it on the next day it didnt start had to get a boost after the boost it starts up qucik, the battery is one year old acdelco.

Start with a test of the charging system. GM has a very high failure rate with their generators due to the design. If one diode is shorted the generator will only develop one third of its capacity which isn't enough to run the electrical system and recharge the battery. Have the system professionally load-tested to see what the output current and voltage are, and pay attention to how high "ripple" is.