Chevy & GMC Vans

Ok this problem started now three days ago. I was visiting an aunt. I had been running the van just about all day and just before visiting i had been on the expressway. Well I go to leave and I try to start the van and I just get one loud click and everything is dead. I mean everything. No locks no chime no nothing. I use her truck to jump it and it started up alright, no problem. The next morning it starts up fine like nothing was ever wrong. I head to work and it starts up there as well to head on my route. I get to one of my stops and i cut the van off and come back out about 30mins later to find all my presets and everything are gone again. However the vans starts fine. I get back to my job after doing anothing hour and a half of driving and I cut it off not thinking about and I immediately try to start it again and it's the same thing stone dead. A couple people try to give me a jump and it ends up setting off the security. I let it set for about 20 min hooked up to a jump box and it starts right up no problem. I then do some more driving and go home and leave back out to go to the store later on and it starts no problem. However after reaching the store and coming back out to leave same no power at all. Try to get a jump and succeed in setting off the security again. I beg the store to let buy a battery. I get one and using my cables I touch off the new one and it fires right up no problem. I take the stuff to my mothers and when I go to leave I put the van in reverse to leave and I'm having to fight to keep the van running. Now this morning I put the new battery in and no problems. I take the other and have it tested and it reads like a brand new battery.

Can anyone help with this problem.

just a guess but check the negitive battery cable where it hooks to the block and to the chassis. I had a ground cable to come loose one day and it did nearly the same thing. As the cable would swing and hit the tie rod the truck would run but if it came off the truck would die.

I'd check the battery connectors too. I've had one come loose before and cause a similar issue.

Check the pos cable where it connects at the firewall, the stud nut may be just a little loose which can cause this.

Check all your battery connections, ie; The Big Three.
You may need to replace them. If you do, upgrade them to a heavier gauge of cable.
If that does not solve your problem, stay away from the store, your moms place, your aunte's and work, as these area's of town seem to effect it the worst.

Peter