If I am reading this correctly, you bypassed the voltage regulator & have the alternator going directly to the battery.

That's not good - it will actually cause you bigger problems - so put it back.

Go get a cheap voltmeter from Harbor Freight, Sears, or whatever store is in your area.

You should be getting about 12.7VDC at the battery when the van is off & about 13.5-14VDC when the van is running.

You need to check the voltage regulator on the firewall & the plug.