My ‘66 Beetle still had the 6 volt system. I got tired of cold morning starts and installed 12 volt motorcycle battery. The headlights were really bright . . . for a while. Don’t ask me about the clutch cables.
The battery and starter on a VDub were in the back of the car, and the ignition switch was in the front on the dash. After a while the wires to the solenoid created resistance that 6 volts couldn’t push through. You would have to crawl under the car and cross the contacts with a screwdriver to start the car. Always had to make sure it wasn’t in gear so it didn’t roll over me.