Modern Vespa

Went to replace the battery on my LXV and one of the two battery cables (see photo) came detached. I think it's the battery ground wire connection. It's unclear where to re-attach it. Anyone willing to advise? No battery = no fun on the scoot.

That looks like a wired-in harness for a battery tender. (To help keep your battery topped up when in storage) Is your scooter working? If not you have a different problem.

Yes, that's a connection for a battery tender. It doesn't need to be there at all for the scooter to start and run.

If you want to reattach it, the red ring terminal goes under the positive battery terminal screw, the black goes under the negative terminal screw. The cover comes off the connector at the other end of the cable and a battery tender can be plugged in there. The lump in the middle is a fuse.

Thanks so much!