My bus started two weeks ago on the old batteries. I run it every two weeks like religiously. Then I had that dead battery issue with the old ones and took them in for a charge. That's when I found out the CCA's were way low.
Still, I reinstalled the old ones and they cranked her up just fine. When they didn't again the next time I traded them in and replaced them. Now I have the same starting issue with the new ones.
I tested them and they each have 12.47v no-load. I checked the neutral ground on the frame and while it feels very solid with no play. It's pretty rusty, should I remove it and clean it up? See:
And here is the positive lead at the other end. As you can see it's pretty oily and nasty down there. I'm sure all of this grime is conductive, could it be involved? Would cleaning it help?
This is from the bottom looking almost straight up from the height of the frame, the red arrows are pointing to the positive lead (you can actually see some of the red insulation through the grime!):
Here is a second view from a little higher, camera is more towards the front and looking more towards the rear. The positive lead terminates with a solid bar (red arrow) and has other wires bolted to it (other red arrow):