Here is a picture of the factory pigtail.
It looks like a 3/8" female flare fitting on the end.
You prolly need something like this:
Would the vents on a box like the NOCO and the hole underneath, where the 12v used to reside, be enough or do I need to find a way to connect the vent hose to the top? How have others set theirs up after switching from 1 to 2 bats?
I added a vent to the top & bottom of the second battery box with PVC fittings and radiator hose.
So educate me. How do I check with a volt meter?
If the digital readout is as shows (12.7) the center is wired to positive.
If the readout is -12.7 the center is wired to Negative.