12V to 6V on 1930 Chummy

[PeterN]

A previous owner installed a secondary 12V battery under the driver's seat, to run the starter motor, the lights and the clock. The ignition circuit is served by a 6V battery under the passenger seat. The system works perfectly and the 6V starter motor certainly looks lively when the 12V hits it.  However, I would much prefer to have the electrical system as originally designed.
 Can I just remove all the wires which currently terminate at the 12V battery and reconnect them to the 6V supply. I'm over simplifying it a little but that's the gist. The coil, the dynamo and the starter are all 6V, I'm not sure about the clock
Is it best practice to install a fuse box or to just use line fuses (I'm adding indicators currently).

["Slack Alice" Simon]

I think so, yes - the lights will need to revert to 6 volt bulbs or units, obviously.

The reason for this reply is to say that the leads from the battery to the starter, and from the battery to the gearbox stud near the starter, need to be extra heavy duty to minimise the voltage drop.

If the previous owner used 'standard' 12 volt leads (whatever that is), it will not work well with a 6 volt system.

And, if not already present, separate earth leads from a common point near to the battery, to every 6 volt thing on the car, will make best use of the few volts that you have.

My car is set up like this, and I smile every time I pull the starter, it whizzes round nicely.

[PeterN]

Thanks for that Simon