It was making it all the way down to 8V? That battery is really dead then. Charge the battery up first, then put it back in the van and check the voltage after that. If it is still swinging and dropping too low then you may have a bad alternator. Even without the alternator, a fully charged battery should read well over 10V with the engine running.

 

Battery was charged and tested and shows voltage 12.98v which meets or exceeds standards Voltage drop test still shows a bounce from 14v to 8 v and lights are still flickering. Im just going to relace the alternator and be done with it. thanks a lot to zero10, mfischer, tizzy1, cougar41, and maxbaby for all your help it was deeply appreciated.

 

Sounds to me like it might be the alternator then. I do recall there being some conversation about decoupling pulleys and the alternator, I don't recall all the details but I'm sure they are on here somewhere. Make sure the right alternator and pulley are installed if it gets replaced.

It takes a heck of a load to drop a car battery down to 8V if it is fully charged and in good condition. Whatever is causing the problem is probably stressing the battery pretty hard, hopefully the battery does not become damaged before the problem is solved.