Yea I figured as much with damaging the battery... I hope I haven't caused too much damage already, it's brand new and I've probably driven about 200 miles with the voltage at 16.5 volts! I didn't have another option though.....

So I've been bypassing it wrong then! I've been disconnecting the two bottom wires and hooking up the battery directly to those posts! It's raining so as soon as there's a break I'll go out there and try again!

Btw, I have a solar setup since I live off-grid and that means I have multiple voltage gauges like my solar controller for example so I know those are accurate! I took both my multimeters and checked my solar batteries and they appear to be working just fine! Not sure why the numbers on the van are fluctuating so much but the meters seam to be reading within 0.15 volts of each other!

I'm going to study the diagram and hopefully understand the circuitry better!
I'm trying to understand what you're talking about when you say there's a more permanent solution and to fire off a relay using the sensing line... You're talking about one of the wires off the ballast? I need to figure out which one of those is the sensing wire and what relay you speak of...
Either way I think I need to just start following wires and cleaning connections!

I'll get out there and do the bypass properly and see what happens and brb.... Cleaning all the connections is going to take a little while...