Center tap battery.

I am looking for the older style center tap battery that allows you use 12v for most everything and pull off 6 volts for accessories on an older car. I have been told you can wire 2- 6 volts in series to get the same effect. I do have some questions regarding grounding. will i just install the 12vlt ground like normal and the the 6 volt items will work fine since they are only reciving 6 volts?


any one done this before? I keep seeing info on 12/24 for busses but not 6/12 for cars.

 

http://www.antiqueautobattery.com/accessories.html

These guys have both the 6/12 batteries and the 12/6 batteries.