Hey folks, Need some help with my 3G alternator. This was installed by the previous owner. I am just getting around to troubleshooting why it is only charging the system at 13.5 volts. At both the batteries and the alternator output post (to rule out charging cable) As far as I can tell, it’s hooked up correctly. The yellow wire goes to battery positive terminal. Green looks like its hooked into the wiring harness, I believe for an indicator light. The white connects to the connector on the alternator you can see in the pic. The charging wire is heavy gauge and goes straight to the battery. The only thing I don't see hooked up is any sort of ground wire, which I see listed as optional in some wiring diagrams, and looking with a mirror at the back of the alternator, I don't see where I would attach one.