8 Volt battery used in a 34 Buick?

[Bloo]

I have seen one of those batteries with the Orpin switch on top that was marketed for a car. A 12 volt battery is just 6 cells where a 6 volt battery would have 3 cells. In the days of tar top batteries with exposed lead cross bars between the cells, it was no problem to configure a 12v battery as two 6v batteries in a 12v case and that is what they did. Then they just put the Orpin switch on top and sold it as an assembly I guess. It would be nearly impossible to build a battery like that that now that all the connections are internal, so you would just have to use 2 batteries.

 

Edited January 31, 2022 by Bloo (see edit history)

[61polara]

Here are photos and wiring diagrams for the 6/12 battery I was discussing above.

 

[jdome]

23 hours ago, 31nash880 said:

Since buying a 1931 nash last year with hard starting issues have heard of using an 8 volt battery . Have retained 6 volt so far and worked out motor issues . Just found this ad today. Of you read car came with 2 unit 6-8 volt battery.  What is it? Can I run an 8 volt without damage?

 

I think the battery voltage reads 6 point 8 volts, not dash, which is what a new, fully charged battery will test. 12 volt battery will test at 13.5. These voltages may  test a couple tenths less with new, modern type batteries. It appears that the above specked cars have dual ignition systems with dual plugs and dual batteries. Dual ignition systems were common up thru the teens. Nash and a few others used them into the 30'3.

 

As others have pointed out, healthy batteries, cables & connections are important, especially with 6 volt systems. You can do quick easy tests of your batty & cable health. With engine off, measure the voltage across the battery on lowest scale that will read the voltage. A good and fully charged 6 volt battery should read 6.6 to 6.8 volts. Anything less could indicate under charged or possibly unacceptable high build up of internal resistance due to age & ware.  Now turn on the low beams. The voltage should not drop more than 1 or 2 tenths under load. Now turn on high beams. Voltage should not drop more than 1 tenth less. If the battery fails this test, it is undercharged or worn out. Now measure the voltage (Hi beams on) across the ground cable at chassis ground and primary cable at the starter (assuming the lights & accessories are connected at the starter). If the cables are good, there should not be any difference in voltage across the ends of the cables compared to the battery under load. Any measurable drop at the cable ends indicates that that the cables have deteriorated or become resistive. One of the problems with DC battery systems is that some electrolyte molecules (sulfuric acid) will migrate  from the battery in the current flow, into the wiring.  Long term damage will occur to the wiring, mostly in the battery cables as the acid & corrosion slowly eats away at the cable conductivity.   Even if a battery has not been connected in decades, once the acid molecules are embedded along with long term exposure to air & moisture, the cable will lose conductivity.  Even if you can't measure the resistance, you can measure the voltage drop effect under load. Always replace both cables with large diameter, #0 or 00 cable. The circuit is only as good as the weakest cable. Most venders that deal with vintage wiring will have appropriate gauge cables for 6 v systems.