Wiring for cigarette lighter 🔋

[JOHN CT]

I did the FB search page, but I'm still confusedI want to install a cigarette lighter socket in to my stock 6 volt positive ground. For charging cell phones,gps,and other low voltage electronics.
So what I did just for a temporary hook up to see if it works It I hooked up a fused wire to the top terminal on the starter (that comes from the battery) to the center post of the cigarette lighter socket. Then the outside terminal connector on the cigarette lighter socket to a head bolt and to other good grounds under the hood
I plugged in my gps and my phone and nothing works. I've tested the center terminal inside the cigarette lighter socket with a test light and I have power then I hooked up my meter just for kicks to see if I have 6.7 volts and I do.
Am I doing something wrong???
Oh ya I tried it with the motor running and not running.